Hey, welcome to our talk today. We'll be talking about decentralized routing for a sharded application on ServiceMesh. I'm Vinay Gauranguntala, and this is Pankaj Sikha. So we are software engineers at Intuit, and we work on the ServiceMesh platform at Intuit. So let me go over the agenda for today. We'll be talking a little bit about what ServiceMesh is and how it is set up at Intuit. A little bit about the sharded application and how routing is done on a sharded application, our design, and some challenges we faced. We'll go over the demo, as well as some future investment we have on the solution. So a little bit about Intuit. Intuit is a leading fintech company. I would consider ourselves more of a leading edge, a platform company. We are really honored to have received the end user award for 2019, as well as 2022. If you look at the CNCF portfolio, Intuit pretty much uses most of the products there. We also are a big open-source contributor. We contribute to more than 75-plus projects, and some of the projects we maintain and our open-source are Argo, Kiko, Admiral, and NUMOproj. So let me go into a little bit of the scale at which Intuit operates. Intuit has more than 245-plus Kubernetes clusters running in production. We span about 16,000 namespaces in those clusters. At peak, we recorded more than 77,000 nodes are running in production with more than 7 million pods. And we have 2,000-plus unique services which are running among these clusters. And these services are a mix of both end user services as well as internal services. So next, I want to just walk through Service Mesh. How many of you here know what Service Mesh is? I think most of you do, so I can go a little fast on this section. Service Mesh is an infrastructure layer to facilitate service-to-service communication. I think the most popular approach right now is to use a sidecar to intercept traffic for ingress and egress communication through the application. This allows us to do a few cool things by adding a sidecar or using Service Mesh. Some of them are security by providing mutual TLS observability, by taking a snapshot of the entire system and finding the bottlenecks, routing by providing things like canary or traffic splitting, and also reliability by automating retries. Some of the most popular Service Mesh offerings out there are Istio, Linkerty, and Console. We had intuited to use Istio as our Service Mesh platform. So there's a little bit about Istio. Since most of you are familiar, I'll just go through this pretty quick. Istio has many services, mainly divided logically into two parts, Control Plane and Data Plane. The Data Plane part is where the service or the application lies, and this is where the communication happens. And to basically maintain or configure these proxies, we have a Control Plane section. And here I'm just mentioning two important components in Istio. One is Pilot and other is Gali. Pilot is responsible for configuring the proxy, and Gali is mainly for user configuration management. And it listens to your request and sends the instructions to Pilot. So at Intuit, we have a multi-cluster Istio setup. So here I'm just representing three clusters with Istio installed individually, Istio Control Plane installed individually in each of these clusters. Now think of a communication, say, from Service C to Service B, which is within the cluster, and Istio is responsible for that. Now, for example, if you think of communication, say, from Service A to Service C, or Service C to Service D, this would require some sort of a multi-cluster setup. We use admiral as our open source or Control Plane component, which manages different Istio resources among these clusters and allows communication between different services here. So now that we have an overview of Service Mesh at Intuit, I'll hand it off to Pankaj. We'll talk a little bit about our use case. Thanks, Vinay. Thanks, Vinay, for the introduction. So before I dive into the details, a little bit about the traffic of the way it's handled at Intuit. So all the north-south traffic at Intuit is handled through Intuit-managed API gateway. And internally, we are going through this journey of moving all these internal application traffic to Service Mesh. While we were going through this journey, we came across this use case where an internal service wanted to talk to a sharded application, which was distributed across multiple shards. Before we get into the details about, so basically what we had to do was solve for which particular shard request needs to go based on the request context. Before we dive into the details, I think I'll touch upon why a sharded application is required and what sharded application is. So think of a normal web application which is fronted by API gateway and has a bunch of users that are making requests to it. As the number of users grow, there's some kind of, some need of some scaling on the web application. One approach to do so is sharding, where the web application splits its data into multiple shards. And API gateway, the way it makes the routing decision to these shards, it could do so by maintaining a static list. But as the number of users grow even further, static list is no longer a viable approach and there's a need for a better solution. Add into it what we do is we have an external lookup service that has the logic and it's using basically the same back end as these web applications. So it knows where the data is sharded and it also has an algorithm to determine the shard where it needs to go to. So gateway makes a call to this lookup service and then it knows what sharded needs to route it to. To make these lookups more efficient, we are also using a distributed cache. So one example of an application that does that into it is QuickBooks Online, which is an accounting software, more than 150,000 companies use it and there are more than five million customers across the globe. So let's look at how this routing looks like when we have to do so on mesh. In this diagram, what you see on the left is service A, which has a sidecar proxy. It's trying to communicate with a sharded application which is distributed among three different charts. So here, the routing decision can be made on the on by proxy or one approach is to let this request go through API gateway as well, but then that introduces an additional hop between the service to service communication and usually the services that talk to each other a lot are co-located within the same cluster, probably also within the same VPC and then this call adds network latency by going out of the VPC and back in and so on. So we can avoid that by using service mesh. So the approach we took was to implement the routing logic within the proxy itself, but before we go there, I want to go through the goals we had for this approach. So as the shards are maintained by the services themselves, we did not want the client to be aware of them. These decisions need to be transparent to the client services as well. So we did not want to have any changes or if any changes, we wanted them to be very minimal there. Also, as I spoke about the QBO use case which shards its data based on the company IDs, we have to handle that and also other applications that have millions of users, they may shard their data based upon a user location, multiple criterias, our solution needed to handle all those use cases as well. So when, imagine I'll go back to the QBO example, when the data in a particular shard grows beyond a certain threshold, there could be a requirement of dividing that data into multiple further shards and this needs to be supported in near real time as well. So we don't want to cause any disruption to the ongoing traffic and the routing decisions still need to be made correctly. As I mentioned earlier, service owners control the routing configuration. We wanted this to be transparent to the client side, so no changes on the client side, we wanted to give this control to the service owners. So we went out and looked at the existing solutions that the service mesh had to offer. Since we were using Istio service mesh, I'll look at Istio examples here. Istio provides a custom resource called virtual service, which defines a set of traffic rules that apply when a given host is at rest. In this example, whenever a request is made to demo dot greeting dot mesh, these traffic rules will apply and each traffic rule defines a protocol and the matching criteria. In this example, company ID one and two, those requests are routed to shard one, whereas the requests for company ID three are routed to shard two. This is very basic example of a virtual service. And but then the virtual service did not work for us due to some limitations due to our use cases. So there were maintainability problems. What I mean by that is if we have to incorporate a routing logic in the virtual service, there has to be some kind of coupling between the sharding logic and it has to go to the virtual service which needs to be created into multiple clusters where the client services exist. So this is a lot of overhead and then also the size of the virtual service object itself can grow a lot, which is again a management problem. As I mentioned earlier, we need near real-time updates. Imagine a new company getting added and we need that sharding info reflected in the virtual service. This is not possible with the virtual service approach. We have to update the virtual service every time a new company gets added across all the shards again, across all the client clusters. And then if the data can move among the shards as well, virtual service as you are aware it's a static mapping so we cannot make that decision in the virtual service. So due to these limitations, we started designing our solution and I'll walk through that approach, what we took. In this diagram we'll see a request that is originating on the, this block is the client that is making a request to a sharded application divided into three different shards. So when an HTTP client makes a request to the sharded application, the on-way proxy intercepts this request as always. So on-way proxy has a filter chain and Istio provides a custom resource called on-way filter that gives the capability to extend the on-way proxy. And we have built the logic in an HTTP filter, HTTP on-way filter that applies to all the sidecar outbound requests. So what this on-way filter does is, as if you remember the API gateway use case, the same lookup service is called to ask where a particular request needs to be routed to based on the request context. And the lookup service responds with the DNS of the shard that it needs to go to. Then within the on-way filter we are able to route the request to that shard. Now this creation of the on-way filter, we have automated this through admiral, which is an open source tool under the Istio ecosystem name space that Intuit manages. So what admiral does is it looks for, defines custom resources that allow it to create on-way filters and other Istio specific resources in the client clusters. So this is how, with this solution, this is how the dynamic routing at Intuit looks like. This typically source service and the destination service live in different clusters. And for admiral lies on top of all the clusters, it watches all the clusters for the custom resources it defines and it creates Istio resources in all the clusters where it needs to to make the mesh, like the life of the mesh operators and developers easier. So for this dynamic routing use case, we introduced a new custom resource called routing policy. Routing policy defines just the config that needs to go to the on-way filter. So the on-way filter can be created with that config. Now admiral watches for it and it has a mapping of all the clusters where a particular services dependencies exist. So it's able to create the on-way filter and the source cluster as well. So this is how the routing policy gets translated to the on-way filter. Now we understand, so this is basically the manifest of a routing policy on the right and how admiral translates it to a on-way filter on the left. If you observe the config section is pretty much the same, it's just that it's rearranged to fit the on-way filter spec. And the on-way filter that we create is also a HTTP filter that matches all the requests that are for the sidecar outbound context. Now we understand the solution. There were some challenges associated with it that I'll walk through. So we use workload selectors which are provided by on-way filter custom resource to match the client workloads where a particular filter needs to apply to. So because the workloads filter can only match one workload as of now, so what it meant for us is that if a given service has 10 different clients in a cluster, we have to create 10 different on-way filters because the OR operation was not supported, we were not able to use that. We also use TinyGo and Wasm for creating our on-way filters. Due to the limitations that TinyGo has, it does not expose full language feature set. We could not use an internal cache within the on-way filter. So we had to create an external caching service to make the calls to the lookup service more efficient. Also, the logic where the on-way filter makes a call to the lookup service and then it also retries based on if the data is present in a shard or not, that logic had to be pre-built in the on-way proxy. We did that because so anytime we need to update that logic, right, we have to rebuild the on-way proxy and then make sure the client workloads are rotated. We had to do that because the version of Istio we were using earlier did not support Wasm plugin, but now with the newer versions, we can use Wasm plugin, which can load all this business logic dynamically. So that's it for the challenges. I'll hand it over to Vinay now. He'll show us a live demo. Thanks, Pankaj. So before I go through the demo, I just want to explain a little bit about the demo setup. So this is how our demo is set up. We have a sharded application with three shards and we have company data in the 9,000 range in shard one, 8,000 range in shard two and 10,000 range in shard three. And we have a call client, which is basically requesting data from this sharded application. And as you saw before, we have a lookup service and a cache lying in between, which gives us the information about the shard. So let me switch the screen here. So this is a Kiali dashboard. Kiali is an observability dashboard, which shows exactly what a traffic is running within a service mesh and within our cluster. So here you don't see any connections because you don't have traffic, live traffic yet, but you can see all the components that I described. We have all the three shards, the client, the router and cache and the lookup service. So let's go to the configuration first. I hope it's visible to everyone. So this is basically the routing policy we are using. In the same spec what Pankaj explained about. So we have a cache section here and we have a host section here. So host section is basically the URL we are gonna use from the client, which gets overwritten to one of the shard URLs. And on the left, I'm doing a watch. So let me rerun the watch once more. So I'm doing a watch on ordinary filters on the client cluster here. So this is gonna update automatically because once I create the routing policy, admiral adds a on-wi filter onto the client cluster. So let me create that. And here you see a new on-wi filter that got created. We can take a look at that on-wi filter to see how it looks. So if you see here, pretty much the same configuration is copied over from the routing policy to the on-wi filter. One thing you can notice is the workload selector. Workload selector applies only to the client here and not to any other workloads. So this is determined by admiral by maintaining a map. Next I have, I'm tailing logs from the different shards. So this is shard one, shard two and shard three. And also I'm tailing logs from a lookup service. So now we know that on-wi filter got applied to a client so I can run some requests from the client section. So let me copy over the request. So I'm just doing a slash company and using the same URL as one we configured before. So now first I will search for something in the 9,000 range and we expect the request to go to shard one and the lookup service. So here you see a log showing up in lookup service. First it looks up where the data for 9,000 is and then routes it to shard one. So rerunning the request multiple times, you see it just goes to shard one because we cache the data inside our service. Similarly if I try request say in the 8,000 range, we expect it to go to shard two and you see a log in lookup service as well as shard two and repeating the request you just see it going to shard two. Similarly I can also do a request on shard three which is a 7,000 range company and you can see that showing up there. So now we can see this a little bit better in the Kiali dashboard. So here you can see client talking to shard one, shard two and shard three and you see some unknown connection happening to router and lookup. Right now Kiali does not have ability to show on-line filter calls. So it shows it up as unknown but basically the filter is making a call to router and lookup, getting the shard DNS, sending it to the, or rewriting it for the client and the client communicates to the multiple shards located here. So now let's go back to the slides. I just wanted to talk a little bit about the future work we planned for this. We want to also add client side rate limiting using the similar approach of creating on-line filter and add the client side and rate limiting it there and services can control that. Also we wanted to work with the Istio community and see if we can enhance the workload selector. I just saw before we have to create one workload selector per client. If you could find a way to add one workload selector per cluster and apply it to all the clients, we would want to explore that approach. Also we use tiny go as our bosom language and we did that because of more familiarity with the golang but tiny go has a limited feature set and we wanted to look at maybe C++ and Rust to enhance the entire solution to better cater for our use case. That's it for the presentation guys. If you have any feedback, please take a snapshot of this and let us know. Also you can talk to us on the admiral channel in the Istio Slack and also we are open for any questions you have on this. We have one here. Yeah, just one, give me one second, just skip. So in the introduction, you mentioned about the shard application for magnetic applications. Can you elaborate more how you shard your magnetic application to the pods? Can you repeat that once more? So you mentioned this is a sharded application, right? For a magnetic application. Can you explain how you shard that? So we sharded based on company IDs right now. Pardon me? Company IDs, I mean the sharding logic is a little more complex. It's based on business logic but we sharded based on the company IDs. So for us, QBO is the application which is a basically a sharded application and we sharded based on company IDs and that could be based on region or based on locality and things like that. So it's a complex logic. It's not just based on IDs of this range. So the sharding logic, we don't need to, for our solution, we don't really need to think about what the logic is for sharding that the applications are using. We as mesh operators, mesh platform owners, what we do is we provide them the capability to have that sharding logic reflect in the lookup service. And from mesh standpoint, we just make a call to the lookup service and it returns the shard that is there. And it could be the sharding logic itself could be depending upon use case, right? For example, QBO, which shards its data based on the company IDs can do so using the company information and it can identify where a request goes to depending upon the request context, right? And then another, like for example, other teams that enter that shard their data based on customer location, for instance, they can just return, you know, get the request context based on the origin and stuff like that. They can return the shard information and all this is managed within the lookup service. But do you do anything to rearchitect your applications to make them sharded? No. I mean, it was built that way. So we didn't, I mean, if you're asking, are we moving to a regular application to sharded? That wasn't the intention. So they are built that way as a sharded application for scaling. Thank you. I think you mentioned about drawbacks of virtual service and limitations for those. Specifically talking about being able to build routes dynamically and possibly growing virtual service. You know, did you consider creating or adding these through controllers? Yeah, so I just wanted to clarify, it's not like a drawback of virtual service itself, but you know, the kind of use cases that we were trying to solve for with virtual service, we could not use it for. So to your question, do we use controllers to update the virtual services? As I mentioned, we already have admiral that is like a management plane for the STO control plane. We already had that in place and that was the easiest route to take and it could potentially update the virtual services, but then we would have to try the sharding logic. Admiral has to know the sharding logic and then update the virtual services accordingly. So we wanted to avoid that complexity. Thank you. Did you notice any latency issue or memory change in memory or CPU usage in the envoy side cut? Good question. So first thing on latency. So initially we were doing a lookup for every request that definitely added a couple of milliseconds of latency. So that's when we introduced our cache. We still have sub-second latest. Latency, but it was acceptable for our solution. And for CPU usage, yes, we do incur a little bit more whenever you add a new envoy filter, but it was negligible to any other solution we were using. Okay, first of all, great presentation. Wonderful engineering. My question is, so on which cluster did you apply the routing policy? So the routing policy, as I said, the service owner controls how the sharding happens and then the routing policy happens on the destination cluster where the service is running. So the service owner defines the routing policy as they also dictate the sharding logic. So that's the config that gets translated to the envoy filter. And so do they apply it on one sharded cluster or an admiral takes care of the rest or do they apply it on every cluster? Yeah, admiral knows where a particular service's dependencies are. There's another custom resource that admiral defines. It's called dependency. That is how, you know, when a service gets created, there's also a dependency custom resource they define which tells them what all clients it needs to apply to. And each workload that is running in our multi-cluster setup has an identity associated with it and it's unique per service. So admiral knows what all clusters, the clients of that application are running in. And that's how it's able to create the envoy filter in those clusters. It can do so in all of them, to your answer. Thank you. So in the client, in the filter that you built, you need to extract the ID to route the shard to or to route the request to. How are you doing that extraction and doesn't that tightly couple your client filter? We don't. Yeah. So the entire logic of that was in the lookup service. We just forward the path, the entire request path to the lookup service. Path and headers. Yeah. Path and headers and lookup service gives it back. That's our implementation. But I mean, as you said, we could, you could, you know, regex it and break it up and send it. So yeah. So our solution just involves lookup service to take care of that information. Yeah. So our solution provides you a capability to define a routing policy, which creates an HTTP sidecar outbound filter on the clients that that service has. What you do with that on the filter is, you know, dependent upon your use case. Okay. Thank you. You mentioned why the virtual routes would not work for your use case. Are there any other methods that you tried or explored that didn't work for any particular reason? I mean, we tried one more, but it wasn't really for this use case. It was the authentic based on my filter. But it wasn't really for this use case that you can do an external call to an authentication service and get and get it back. But that didn't give us, that doesn't give you a metadata back. It just gives you 200. Okay. And forwards the request. So that kind of didn't work for our favor. So yeah. That's right. Also, we wanted to, you know, any other solutions did not give us the flexibility to adapt our solution for multiple use cases. As I mentioned, QBO charges data based on a company and then other multiple other applications that tend to it with millions of users. They shot their data based on user data. So we wanted to support those and routing policy allows us to give this flexibility to the service owners to define the config they want to use and also, you know, define the lookup service that needs to be used for that. Yeah. If you guys want to try this out, we will push this up onto the admiral repo, which is part of the STO ecosystem. So yeah, this feature is live on admiral. So you guys can play with it as well. All right. There's a question. Yeah. So I have one question regarding, so when the source cluster you have created on my filter, right? There is a VM underscore code section and you have added a binary called wasm binary, right? How do you guys are storing that binary in the container? Yeah. Because we had some issue with binary storing the container because we build the binary and we created some config map and the config map supports are like 100 MB of some maximum. If it is more than that, it cannot even store, right? Yeah. So what we did it basically, we use the engine x proxy and we put all the binaries in there and then we are calling that engine x wasm binary from the container. So how you guys like, if the binary is like more than 100 MB or like how you guys are like using it? I mean, a very good question. So for this solution, right? I'm not sure if this is what you wanted to hear, but for this solution, we prebuilt the on my proxy. We have a, we just do a copy of the wasm binary into the on my proxy image. And we just reference it in our on my filter. Yeah. So this is the reason for this is we used 1.10 and below Istio when we designed the solution and that was the approach we took. But wasm plugins would give you that opportunity, right? Yes, we tried it, but at that time this was like authentication problem was issues. I'm not sure how it was when we tried it around like one year back. Yeah. Wasm plugin, we did some POCs with it. It worked for us. We pull it from something like Artifactory or a Docker hub and it works just fine. Yeah. And did you mention that there's a limit of 100 MB for that plugin to be loaded? No, I'm saying in Copenhagen we've tried with like config maps. Oh, the config map is exceeding the limit that it CD allows. Our wasm binary was more than 100 MB but it was not fine. Got it. Got it. And if you're writing a wasm plugin more than 100 MB, that's pretty much, I don't know. I'm just saying it's pretty big. I do believe that's all the time we have for questions today. Thank you. Thank you. Thank you.


Let us start our today's lecture on this NPTEL video course on geotechnical earthquake engineering. Let us start our next module which is module 7. Let us look at the slide. So module 7 is on seismic hazard analysis. So what is seismic hazard? Let us see. Seismic hazard is nothing but the probability of experiencing a specific ground shaking at a specific site or region due to earthquake. So that is the probability by which at a particular site, the earthquake will be felt or shaken. So that seismic hazard analysis can be done through basic two major methods. What are those two major methods? These are two major methods. One is called deterministic seismic hazard analysis. In short, it is called DSHA taking their initial letters that is DSHA which is nothing but ground motion hazard evaluation based on a particular scenario earthquake. On a particular scenario earthquake that is the important part we should note and another type of seismic hazard analysis is called probabilistic seismic hazard analysis or PSHA taking again the first letter of each word that is probabilistic seismic hazard analysis PSHA. In this case, we consider the uncertainties involved in the size of earthquake, in the location of earthquake and at the rate of recurrence that is in the interval through which earthquake repeats or reoccur that of earthquake considering uncertainties involved in all these parameters then this PSHA or probabilistic seismic hazard analysis is done that was initially developed by Cornel in 1968. So the seismic hazard analysis it involves the quantitative estimation of ground shaking hazards at a particular site and it can be analyzed through deterministically and probabilistically or probabilistically that is these are the two ways through which seismic hazard can be analyzed that is DSHA and PSHA. So how we go ahead further first step to do the seismic hazard analysis is to identify the earthquake sources that is the very first step. So to identify the earthquake sources what are the characteristics we should look into like geologic evidence of the earthquake that is from the historical earthquake, the fault activity we should note down the fault activity for past earthquakes, tectonic evidence, any tectonic movements etcetera, historical seismicity at that particular site or in close vicinity what are the various previous earthquake and instrumental seismicity that is through the recording stations what are the recorded values of seismicity of a particular site over the years. So these all together will help us to identify what are the various earthquake sources for a particular site for which we are going to do the seismic hazard analysis. So in the deterministic seismic hazard analysis it is the earliest approach taken for the seismic hazard analysis it is originated in nuclear power industry applications and still it is in use for significant structures that is for nuclear power plants for large dams for large bridges for hazardous waste contaminant facilities etcetera. That means you can see all the important or very important structures where the destruction of these structures during earthquake can be a huge disaster in that area also in an area surrounding that particular area for those cases we should consider or we should apply this deterministic seismic hazard analysis or DSHA. So DSHA it produces a scenario earthquake for design that is the design earthquake. So DSHA considered only one particular earthquake as we have already mentioned it is based on one particular earthquake which is nothing but a design earthquake or scenario earthquake for a particular region. So as commonly used it produces the worst case scenario. So obviously when we are trying to do the design of the seismic hazard analysis through the deterministic approach we should take the worst case that is what is the maximum magnitude in that region it occurred. So that what it meant that it is commonly used produces the worst scenario case. The DSHA provides no indication of how likely that design earthquake is to occur during the lifetime of the structure. So this is one disadvantage of DSHA why because when you are considering the worst case scenario or the highest value of earthquake you never know that whether that design or worst case or the highest value of earthquake will ever occur during the lifespan of your structure or not. It may happen that from the past historical earthquake of say several of hundreds of years you have chosen the highest value of earthquake for designing your nuclear power plant or large bridge etcetera. But you never know suppose the lifespan of that structure is 100 years or so that highest magnitude of earthquake may never come. So that is one of the limitation or because it never provides any kind of indication that it should be considered based on the likelihood of that occurrence of the design earthquake. Now let us come to the seismic sources that is identification of seismic sources through various methods as we have already mentioned like geologic evidence you have to find out what are these seismic sources of this fault etcetera. Geologic evidence of past earthquake field reconnaissance that is field survey you can do trench login. You can do the trench login at a particular site to identify a fault, test pits and boardings method, air photo interpretation you can have aerial photograph of a particular region to identify an open fault or the surface fault stress. Remote sensing through the process of remote sensing using the geophysics geophysical methods non-destructive methods you can identify the fault. Historical seismicity from the past earthquake historical records which you may have for that particular location and based on the instrumental seismicity of current days you can use the recorded earthquake motions etcetera from the seismograms and those seismogram data you can use to identify the seismic sources. So these are the various ways so either you have to use the combinations of them or a particular of them it is always better to apply a combination of these methods to identify the seismic sources. So coming to the trench login this is the picture which is presented by Swan et al in 1980 and modified after squads in 1988. This is various trenches looking at the zone of slumping and the backfill and the material property etcetera you can see the pond deposit, colovium, transitional deposit etcetera depending on types of material you can comment on the previous seismicity using this lithologic unit behavior and distance from your main fault in this directions. Also we have seen earlier what are the various types of fault like normal fault, reverse fault, strike slip fault, oblique fault etcetera. So depending on the fault type you have to identify what type of or what are the chances of seismic sources you may have at a particular site. So when we talk about this various seismic sources so source zones may consist of a mapped fault which is known from your fault geometry like areas of high seismicity where for a particular area you have a fault which is already mapped that is you know the fault geometry completely depending on area of high seismicity area of shallow or outcropping bedrock because if the bedrock is outcropped means that bedrock comes open or to the ground surface that is called outcropping of the bedrock. So those areas and areas of sparse surfacial vegetation in these areas you will have a mapped fault which from the known fault geometry which can be considered as a identification for your seismic source. For example for California region we have already available this mapped fault whereas you may have another type of region or source zone where your fault geometry may not be known that is called as diffuse zone. What are those areas? Those areas are nothing like areas of low seismicity where earthquake is not that frequent or common or that high magnitude. Areas with significant sediment cover where you have large thick cover of a soft sedimental layer and areas with dense vegetation cover here you have less vegetation cover here you have dense vegetation cover. So those area it is very difficult to identify your fault or surface stress of the fault. So those area it will be considered as diffuse zone but there also we need to identify the source zone some way or other we will see the various ways. For example such type of diffuse zone can be considered like Washington is considered as a diffuse zone where fault geometry is somewhat unknown compared to the California region. Coming to the fault activity we need to check whether that fault various types of fault what we have seen whether it is an active fault or a dormant fault. What is active fault? That is where still the occurrence of earthquake is keep on happening. Now let us see what are the guidelines available in various specifications or codal guidelines or stipulations like U S nuclear regulatory commission they define the active fault means movement at or near the ground surface at least once in the past 35,000 of years or movement of a recurring nature within the past 500,000 years then they called it as a active fault. That means you will see most of the fault which you will get are nothing but active fault because this period automatically shows it is in the human era of what we are considering as years of civilization we have to consider almost all fault as an active fault all identified fault as an active fault as per this U S nuclear regulatory commission. Also another statement they made macrosismicity instrumentally determined with records of sufficient precision to demonstrate a direct relationship with the fault that is suppose there is no such definite fault activity but you have some macrosismicity which is recorded instrumentally which is not may be perceptible or noticeable to the human being but noticed by the instruments even those faults also U S nuclear regulatory commission they are considering as an active fault though they generate a very minor or small magnitude of earthquake or a structural relationship to a capable fault according to the previous two characteristics like this such that the movement on one could reasonably be expected to be accompanied by the movement on the other. So, any kind of movement on the structural relationship between two plates between two fault plane can be considered as the active fault based on their fault activity. Now, coming to the magnitude indicators next step we need to find out how to estimate the earthquake magnitude for this seismic hazard analysis this magnitude is nothing but a function of this energy released that we know that is the best magnitude which is that magnitude we already have mentioned that is the moment magnitude. So, e should increase with increasing dimensions of the rupture surface because if during an earthquake energy releases more that means more rupture will occur am I right the seismic energy gets erupted more means more opening or more rupture of the fault will occur will take place. So, that shows the relationship as proposed by Wells and Coppersmith in 1994 for various types of faults how to estimate the moment magnitude of earthquake based on the area of that fault rupture. So, what are the equations they proposed for all over the world they mentioned that for strike slip type of fault m w can be calculated the earthquake moment magnitude can be calculated if we know the how much fault rupture area is having that is knowing the fault rupture area in kilometer square unit in this empirical relation that is why we have to be careful about this unit it is in kilometer square. If you put this value of a when it is a strike slip type of fault you will get what is the value of your earthquake magnitude similarly if it is a reverse fault what should be the m w can be used can be obtained using this equation similarly if it is a normal type of fault it can be estimated using this expression if it is any type of fault that is all types of fault that is if you are not sure about what type of fault then you should use this equation that is which is valid for all type of faults like this. Now, you should know what is the origin of this development of these equations Wells and Coppersmith collected several historical earthquake available before this 1994 knowing their fault rupture pattern what type of fault and combining them he did they did a combined analysis of assembling all these historical earthquake data and plotted them in this form we will see this slide moment magnitude versus surface rupture length in kilometer this is for length for various strike slip reverse fault and normal fault for 77 recorded earthquake they propose they put all the points and then they use this regression equation which best fit those points also for the earthquake moment magnitude versus rupture area it should be in kilometer square it is a wrongly shown it should be kilometer square you can correct it for all types of strike slip reverse and normal fault from 148 recorded earthquake data also from moment magnitude versus maximum displacement of the fault that is the maximum slip of the fault which is in meter unit that for various strike slip reverse and normal fault for 80 recorded earthquake points and then using the regression relation they have proposed the equation. Now, let us come back to this slide these are the equations which are proposed by Wells and Coppersmith in 1994 these are empirical relationships between moment magnitude M W of earthquake and surface rupture length L in the unit of kilometer rupture area A in kilometer square and maximum surface displacement or surface slip in the unit meter we generally use the symbol D. So, these are the equations you can see they have also mentioned how many number of events they consider to propose that semi empirical relationship. So, for strike slip fault 43 events to propose this M W versus that rupture length relationship what is the sigma M W that is nothing, but the standard deviation which occurs for all the 43 points with respect to this proposed relation right and this is the relationship in log scale that is after reshuffling this. So, what is the standard deviation of this log of value of this length in terms of A and D B D that is for this first equation this log of L is this much value. So, in log scale the standard deviation is lesser. So, that is why one can use this equation though it is a rearrange in this format that is what it is shown in the log scale the points are pretty close to the proposed equation. Can you see now if we compare this three relationship three sets of relationship that is one set is for with respect to rupture length L another set is for rupture area kilometer square another set is for maximum displacement or slip in terms of D which one is the best one in terms of the scatter is concerned we can see the rupture area is the best one because here it all are clustered through that best fit equation which they have proposed that is why if you look at here first four equations trike slip fault reverse fault normal fault and all fault this is for length based surface rupture length. Then next four is for rupture area based and last four are for surface displacement based and among them the least value of standard deviation you will get for this rupture area because the scatter is less. Can you notice here it is clearly shown whether you consider the standard deviation of M W in normal scale or standard deviation of that log of either length or area or slip in this log scale. So, in both the cases we found this portion of equations in terms of surface rupture length or surface rupture area of the fault in terms of kilometer square is the best fit equations compared to the length and displacement. Now, if we want to see what is the next best or next better proposed semi empirical relationship as given by Wells and Coppersmith that is with respect to the rupture length that is with respect to L. Suppose at some fault you do not have the information about rupture area you know only the surface stress of the rupture fault length. You can use that length and you can compute the M W if you are sure about what type of fault movement otherwise use the equation for all fault equation which can be used for estimation of M W. That is why in this slide we have mentioned that these are the best recommended equations of Wells and Coppersmith for magnitude calculation for a particular earthquake using the fault geometry using the fault rupture area and types of faults also. Now, let us move to tectonic evidence for tectonic evidence how we can compute the magnitude of earthquake like we have seen now through the fault characteristics that is either from the fault length or rupture area or surface displacement we can compute the moment magnitude of earthquake. Now, we are looking at through the tectonic evidence or plate movement how we can find out this moment magnitude of earthquake. So, plate tectonics and elastic rebound theory give information about the earthquake to relieve the strain energy which gets accumulated as plates move relative to each other. So, that is what happens during the plate movement in plate tectonic theory we have learned that. Now, for major subduction zone rough and conamory in 1980 related the maximum moment magnitude to both the rate of convergence and the age of the subducted slab. So, what is the proposed equation by rough and conamory that is M W equals to minus of 0.0089 of t plus 0.134 times v plus 7.96. Again, this is semi empirical relationship or empirical equation. So, we have to be careful about the unit of this t and v. So, what are these things let us see where this t is the age in the millions of years age of that tectonics slab and v this v is the rate of convergence through which two plates are converging with respect to each other right. So, that rate of convergence expressed in the unit of centimeter per year. So, if from the geologist one can get these two informations that is what is the rate of convergence between two plates and what is the age of that plate in million of years unit then we can easily put those values in this equation and compute the possible values of maximum M W which can come from that major subduction zone using this relationship. So, either you can use the maximum available historical earthquake data value from that you can take M W for your hazard analysis or estimation or if you do not have very well documented historical data what you can do from the recent data given by the geologist you get the values of this t and v use this equation to get the maximum possible value of earthquake which can occur in that subduction zone due to the plate tectonic movement that is what it shows clear. So, the same equation so this tectonic evidence how it was proposed and further modified like this first equation you can see it was proposed by rough and Kanamori in 1980 then later on it was slightly modified by Hayton and Kanamori in 1984 what was the changes they incorporated more number of earthquake data during this four year period. So, that is what you can see over here they propose this figure through which they have shown all the collected data of earthquake till that time rate of convergence in the y axis in the unit of centimeter per year and in the x axis the age of that plate tectonic in millions of years before the present. So, if 0 is the present day that is suppose in 1984 they have proposed that they considered as a present age then age of that plates in those many millions of years then they proposed different demarcations of area to highlight what are the values of various magnitude of earthquake which they have recorded all over the world you can see New Zealand earthquake, Sumatra earthquake, Chile earthquake, South Chile earthquake, Columbia earthquake, American earthquake, South West Japan earthquake etcetera. So, using those points they have proposed finally, this equation. Now, let us come to next important part of this hazard analysis which is known as segmentation first is magnitude indicators that is first we have to find out the magnitude of earthquake which we have done using either the fault characteristics if it is a fault based earthquake or we have done it through the plate tectonic movement if it is a plate tectonic based earthquake. Now, we have to segment the earthquake that is earthquake segmentation let us see how we do this earthquake segmentation that is those parts of the fault that have ruptured during individual earthquake or nothing but the earthquake segments that is within the active fault only those parts of the fault which have ruptured during your period of consideration like for deterministic seismic hazard analysis we have seen almost every fault is active fault because they say some several of thousands of years ago whichever earthquake fault was responsible for earthquake that can be considered as active fault. So, from that fault characteristics one can find out what are the earthquake segments of a particular fault. So, for example, one example is given over here that is Wasatch fault zone of Uttar region in US there are 8 segments have been found and Provo segment which is 70 kilometer is the longest one among those 8 segments within a fault that is among those ruptured portion of the fault which are nothing but the segments you have to identify how many segments are responsible for your hazard analysis and accordingly you have to take the values of those. So, in this slide we are now looking at segment length or area can constrain magnitude segments bounded by discontinuities then geometric discontinuities like suppose there is an abrupt change in the strike step overs gaps etcetera need to be considered then structural discontinuity of these segments like fault bifurcation suppose there was a fault going in a particular direction then there is a bifurcation from that fault there is another sub fault or another sub rupture has been formed. So, that bifurcation that segment also needs to be taken care of zones of increased structural complexity intersections with other structures behavioral discontinuities changes in slip rates senses of displacement and creeping versus locked behavior. So, all these characteristics of properties needs to be considered when we are trying to identify a segment earthquake segment clear. So, this is a picture which shows the cross section of Juande Fuka subduction zone you can see over here this is Juande Fuka plate of earthquake this is that plate and this is North American plate this is Pacific ocean over here you have source area for subduction of earthquake this is the portion. Now, North American plate earthquakes are clustered these are typically the shallow events whereas, here you have the deep events at these locations below the sea pacific ocean over here and this is the western part of the Washington. So, that is how you have to find out the subduction zone and once you get the subduction zone then next step will be to identify which portion or which segments are responsible for particular earthquake. Now, this deterministic seismic hazard analysis where as we have initiated we have seen that earliest this is the earliest approach taken for any seismic hazard analysis. It is the oldest approach and this is the simplest approach that we have mentioned. It is originated in nuclear power industry applications like we have seen what are the areas we can apply what are the important structures where the deterministic seismic hazard analysis is still used even today also. So, this originated from that design consideration of a nuclear power plant. So, still used for some significant structures or important structures those are nuclear power plants, large dams, large bridges, hazardous waste containment facilities. So, any kind of very important structures as you can see damage of which is associated with a very severe amount of loss of property and human being like suppose if a dam breaks obviously, you can expect there will be a big amount of loss on the downstream of the dam because there will be a probably a society entire society may live on the downstream of a particular dam which is quite possible at some places. So, that is the reason why for these mentioned structures one needs to be taken utmost caution or maximum caution that is why though this is the earliest and simplest approach considering the worst case scenario. We have mentioned that already it considers the worst case scenario to estimate the hazard analysis or to estimate the design, but still today also it is in use for design for these particular structures or these particular sites where these structures will come up in future. Like for India suppose if we plan for a proposed nuclear power plant at a particular site if you want to go for seismic hazard analysis you have to go for deterministic seismic hazard analysis only. Probabilistic will be more logical technically yes, but that can be considered as a subsection or just a kind of a looking from the technical point of view how much it vary from your design value which is proposed through the deterministic seismic hazard analysis. So, you can see over here it is mentioned as a cap for the probabilistic analysis why it is mentioned as a cap? Cap means there is nothing beyond that because in the deterministic analysis what you are proposing the design data say suppose design seismic acceleration peak horizontal acceleration or design value of peak horizontal velocity for a particular site. After doing the hazard analysis taking all the nearby faults into consideration segments etcetera magnitude indicators everything then whatever value you will get from this deterministic seismic hazard analysis that will be the maximum possible or the worst case or design basis value based on this maximum case whereas probabilistic value considering several uncertainties involved in this process will give you obviously little lower than or may be at maximum to that level value, but not beyond that that is the reason why deterministic seismic hazard analysis values are called as cap of the or maximum of the probabilistic seismic hazard value that is why you can see over here it is mentioned in the slide it is a cap for probabilistic analysis that is suppose after doing the analysis you get your result as probabilistic seismic hazard value is giving you the higher one than deterministic seismic hazard analysis that shows you have made a mistake in your calculation that is the only consideration or output or conclusion one can draw from the results. Now let us see what are the guidelines proposed by this corpse of engineers regulation of USA through this clause number and section number of their manual which is of 1995 version deterministic seismic hazard analysis or DSHA the clause says the DSHA approach uses the known seismic sources sufficiently near to the site and available seismic and geological data to generate discrete single valued events or models of ground motion at the site. So, first of all it considers all the known seismic sources known seismic sources means wherever you have identified the fault or if you know what are the plate tectonic movements are involved or close to that proposed site. So, these are sufficiently near to the site that how much sufficient that quantification depends on your analysis sometimes some people say it is within 100 kilometer some people say within 200 kilometer some people say within 250 kilometer some people say 300 kilometer. So, that depends on your designer's choice or the decision of an engineer who is going to find out the design value for construction of a structure. So, near to the site and remember this near ranges in terms of several kilometers not few meters only because fault etcetera geologic fault etcetera can run for several kilometers that we have seen already that is the reason why it is not only few meters it has to be in several kilometers. Now, from available historical seismic and geological data also should be available which should be used to generate the discrete and single valued events of the model of ground motion at the site. So, it should be independent from all the different sources and finally, you should get a single value should be proposed for that site. We will further discuss when we will carry out the analysis and steps and also example problem very soon. So, the sing typically one or more earthquakes are specified by magnitude and location with respect to the site. So, with respect to your proposed site where you are going to design or construct your new structure with respect to that you have to find out possible near sources and for all sources we have to find out how much magnitude of earthquake can occur in those sources and the location of those sources that is what it means. So, usually the earthquakes are assumed to occur on the portion of the site closest to the source. The site ground motions are estimated deterministically given the magnitude source to site distance and the site condition. So, let us see what are the various steps of doing this deterministic seismic hazard analysis. There are major four steps involved in this deterministic seismic hazard analysis. What are those four major steps? First step is identification and characterization of all sources that is you first identify all seismic sources close to your proposed site and characterize them that is what type of source I will come to that very soon. Next step is selection of source to site distance parameter that is from your proposed site to the earthquake sources. What are the distance parameters? What are the relevant distance you should consider etcetera? Third point is selection of controlling earthquake means among all the sources which source earthquake controls for your chosen or proposed site that you have to identify. And fourth step or last step is definition of the hazard using that concept of this controlling earthquake for your proposed site. So, that will give you the final hazard value for your proposed site. Now, let us see pictorially how it looks like all these four steps which I have mentioned just now. So, DSHA methodology involves these four steps step one, step two, step three and step four. So, step one is identification and characterization of sources. Suppose this is your proposed site you may have several types of faults close to that you have to identify all those faults that is what are the sources of earthquake from past historical data. And if it is a plate boundary from the tectonic plate movement from plate movement theory you have to find out their magnitude you need to find out and from the fault characteristics everything you need to find out after identifying the faults. Now, these faults can be sometimes like this which is linear fault sometimes it can be like this which is called as area fault sometimes it can be a single point which is a point source or point fault. So, several types of shapes of these faults are possible. So, next what you need to do you need to identify which one is the controlling earthquake. To identify the controlling earthquake you need to do two things one is fixed the distance r what is the distance from this site to all these sources you need to find out all these distances. When you are talking about distance which distance you should take like from this site to this fault there will be this is one distance this is another distance this is another distance this is another distance there can be several possible distance. Obviously you have to take the minimum of those all distances right that gives you the worst case scenario or design scenario which we consider for our deterministic seismic hazard analysis. So, you have to take the minimum distance from that site to all these sources and you have to fix the magnitude of earthquake that is for each of the fault there will be certain magnitude maximum magnitude of earthquake which either you can get using that Wells and Coppersmith equation using the fault dimensions or if it is a plate boundary you can use that Kanamori's equation Hettian Kanamori's equation to find out the magnitude of earthquake which are possible in these sources or from historical data you will have the maximum value recorded at those faults. So, using all those data you have to fix the what is the maximum of all those values of the magnitude of earthquake. Now next step is ground motion. Now ground motion it depends which parameter you are looking at. Suppose you want to get the design value of peak acceleration if somebody wants peak velocity it can be peak velocity if somebody wants intensity it can be intensity. So, it depends on which parameter you want to find out as your hazard parameter. For that you need to use the proper attenuation relationship that is with respect to distance how that parameter is changing from your particular source that is from each source you will have for that particular locality a particular attenuation relationship available for a hazard parameter say peak acceleration like this then within that depending on your site source distances maximum magnitude and minimum distance you can identify what is your that hazard value or design parameter for your site. So, in the fourth step you report that hazard at the site which needs to be considered for your design of the structure at this proposed site. So, the earthquake hazard for the site is a peak ground acceleration because we are showing here peak acceleration that is why it is mentioned peak acceleration just and value is shown say for acceleration of 0.35 g resulting from an earthquake magnitude of say 6 which is the controlling earthquake on say some fault at a particular distance at 12 miles which is a minimum distance from the site. So, this is just a typical example is shown how final data or final output of the result is reported for your design. So, this is the final output of your seismic hazard analysis using this deterministic approach. So, now let us see again this identification and characterization of all sources like all sources are capable of producing significant ground motion at the site that is one major assumption in this deterministic seismic hazard analysis remember it is considering all sources are equally important. It is not that suppose among those sources may be few sources are showing very active events in the near future you cannot give more weightage to those sources which are more active in the near future. In deterministic approach you cannot give different weightage to different sources that is what it shows that all sources are assumed to produce the significant ground motion at the site that means all sources has to be taken care of with equal weightage large sources at long distances small sources at short distances all this should be considered. Now, how that is fixed I will come to that very soon characterization like definition of the source geometry definition of source geometry means what type of source it is as just few minutes back I mentioned it can be a point source it can be an area source it can be a line source it can be a volume source etcetera. So, that definition of that source geometry should be characterized and the establishment of the earthquake potential needs to be checked. So, now for the establishment of that earthquake potential it is to be estimated by the seismologist geologist engineers risk analyst economist social scientist and government officials together remember that what is that earthquake potential for a particular site or for a particular source that needs to be estimated or identified by all these people involved it is not only the job of a particular community it is a job of all together seismologist geologist engineers risk analyst economist social scientist and government officials why because of course the seismologist geologist engineers they will give the technical values. Now, the risk analyst will check whether those values are really admissible or feasible for that particular site suppose engineers and seismologist gave some value of earthquake potential at a particular location where there is no inhabitants like there is no mankind in staying there then what is the risk involved you understood the point why the role of an risk analyst also come into picture. So, risk analyst is supposed to do the risk estimation economist that is also why important because they have to they need to provide the data how the economy of that particular region where you are proposing a new site for the calculation of this hazard analysis how it is changing suppose if it is a stable economy obviously in that case they can probably take a little extra risk than at a particular location where economy is not stable not good economy if it is a poor economy then it is very difficult to take a risk for a major say nuclear power plant is going to get a commission or starting at a particular site they cannot take risk. So, that economist role is also important can you see that social scientist what the social scientist do social scientist also see all the social aspects related to the mankind like their usage pattern of that proposed utility or structural suppose whether a nuclear power plant or a large dam which is proposed to be commissioned at that place how much need for that at a particular location for the human being from the social point of view they will take all the possible data and information then government officials they are obviously required to provide the all not only the all government support but also they are the policy makers suppose all these people have proposed something and suppose government officials do not allow it to occur then obviously finally the project will not run. So, that is the job of all these group of people together to establish the earthquake potential for a source to site to do the deterministic or any kind of seismic hazard analysis now to do that what are the various terms technical terms which are used to describe the earthquake potential these are listed over here these are common terms which are used to describe this earthquake potential first one is called maximum credible earthquake which is the short form is m c e next is called design basis earthquake which is called d b e another terminology is safe shutdown earthquake which is the short form is s s e maximum probable earthquake the short form is m p e operating basis earthquake o b e seismic safety evaluation earthquake s s e e. So, these are the common terms which are conventionally used to estimate or to describe the earthquake potential of a particular source. So, we will see their definitions and application in our next lecture. So, with this we have come to the end of today's lecture we will continue further in our next lecture.


The City of Prestonsburg will be holding their fireworks display on Saturday, July 30th in honor and remembrance of the three fallen officers and the K-9 Drago. We have a huge fireworks show, although we haven't stored safely and we haven't stored effectively, we feel that storage over a long period of time could deteriorate, let some of the last some deteriorate, so we have to shoot them. But we also want to do it in remembrance and in honor of the police officers and of course some for Drago too and we feel like the 30th there's a concert going on over at the burn run at Archer Park, Sunday best is going to be performing, and we feel like that is a good opportunity for us to shoot fireworks off on the 30th. There will be no parade, there will be no Star City day, that will all occur later on in the year, but we're going to do it in remembrance and honor of them and we feel like it's a very, it will be a very effective way and a very honorable way to share their memory. This life of time that's given to us all, it is all in our hands, it is all in our hands. Experienced heart specialist and subspecialist collaborating for the benefit of your care. Top 10% national hospital rankings for patient safety and heart attack and heart failure treatment. The technology is skilled to perform extraordinary complex minimally invasive cardiac, electrophysiology, interventional and structural heart surgeries. This is a heart and vascular institute at Pikeville Medical Center. When it comes to your heart, place your care in our hands. Following the shooting in Allen, Prestonsburg canceled their 4th of July fireworks display in observance of the tragedy. The July 30th show will begin with a siren signaling the beginning of the display. The first shot will be in honor of the firefighters, the next shot will be for Drago, and three large shots will follow in honor of each fallen officer. 30 seconds of silence will follow these shots, and then the fireworks show will begin. You know the entire community is just devastated, surprised, and just like someone who's grieving, they're going to go through the same phases as a community. There's going to be the now. It can't happen in a small town. There will be self-doubt. How do we let it get by? And there's going to be anger. We've got to do something. And you know, a community as a whole goes through the same different aspects of grieving as an individual does. And we have to try to control that as a community, and we have to try to be aware of the frustration that comes with that. And we eventually have to start healing and start moving forward. The fireworks display in honor of the fallen officers in Drago will be held at Archer Park on Saturday, July 30th at nightfall. For Mountain Top News, I'm Kelsey Dean.


Welcome to Toffy TV it is the Everton News Daily Frank Lampard has held his press conference ahead of Saturday's game with Southampton with some mixed injury news for Tally Michael Enco is available once again after Covid and the question will be will he get his place back in the side? The manager was asked about the start lineup and whether he'll keep it winning side and he said well basically I tried to do that against Newcastle and look how that turned out so he's going to be having a look at the situation, having a look at the way Southampton play and deciding which team will be the best to face the Saints. One player who will not be playing is Damari Grey who's not quite ready for this week but should be ready for next week's game against Manchester City so he'll be available so that gives a good chance for Alex O'Woby to start again after his game against Leeds which he was excellent in so a good chance for him to play again but we'll wait and see. The manager also spoke about Abdelhaid D'Corey and he said he's back on the grass training he's done the warm-ups with them which is not full training obviously but he's done the warm-up session with them so he's back on the grass and he said hopefully maybe for the Manchester City game or simply the boring word game in the FA Cup he could be available to come back into the midfield and that will give him another option in there. Obviously in the last game out Alan and Donnie van der Beek did really well and it will obviously mean that he wants to switch to a three or play with D'Corey and van der Beek or it just gives him more options simply which is always better for the manager and better for the chances of winning a game so hopefully we get to see D'Corey back in the next couple of weeks. He spoke about Ben Godfrey as well and said he's getting closer but I don't think the time scale is any different I don't think he's had any, he's been in any way accelerated his rehabilitation but it looks like he's on that scale so he should be back on maybe three weeks time. Delft the same, nothing new on him and Mina is back in the gym I think but again it's still Mina's season could be over but it's going to be the back end of April till we see Mina but the manager is just trying to be positive. I don't think there's much change on any of them I think he was just trying to be positive the way he said it as well so the manager was obviously positive about the game as well spoke very very well and as I said he said you know keeping the same winning sides and always the best thing to do you've got to possibly change things for the opponent so we'll wait and see how he looks at the side at two o'clock on Saturday before the three o'clock kick off. Tom Davis has confirmed that he is out for the season he put a post on Instagram and he replied to one of the messages asking him when he'd be back and he said he was out for the season I think it was pretty much what we already knew he'd not been putting the Premier League squad so that pretty much ruled him out anyway but he's obviously himself not going to be back he is in the gym there's lots of videos and stuff in the gym. He's got a nasty scar on the back of his leg from the operation so and for Tom it's a real first bad injury I think he's suffered in his career rarely he's had he's been you know in and out of the side but to have an operation and see the scar is just shows you how bad it was and couldn't have come at a worse time I suppose for him with a new manager coming in and a chance to prove himself we've been pretty light in midfield in the last few weeks as well so unfortunately for him he's out and he's out for the rest of the season so. But he did say in recent interview he did that it's given him a new appreciation and a new love for football. He might you know he said he'd been finding himself sort of not drifting away but it wasn't the biggest thing but he said he's been just consuming football like never before because he's not been playing so and I imagine when it's your job it can be a bit like that you look for the other things and this is a kid who does a lot of really good things. You know in for society but he obviously does a lot of things which don't normally get done by the average footballer but you know he said that getting back to being away from football is you know is meant that getting back is the most important thing for him now when he's been really consuming it and you know that might make him a better player he might appreciate where he is and what he's got and want to work a lot harder to improve himself so we'll wait and see. The other bit of news today is former Everton coach and caretaker manager Steve Barton Shaw has passed away at the age of 86 he was the caretaker for Everton for three games in the 70s a lot of all the viewers will know who he is but he has passed away today so rest in peace to Steve. There you go this has been the Everton news daily make sure to check out our match preview it is available now go check that out give this video a like and if you want to join us on page and please do the link is in the description and it's on the screen now we do daily live videos as well as a lot of exclusive videos as well over there go check that out thanks for watching see you later.


And last but not least, I cannot wrap up this Etsy video without recommending some really, really good Etsy Chrome extensions to use for your store. I already talked about Etsy apps that you can integrate with on your store, but here I'm gonna talk about Chrome extensions, which is an extension and add on it. You can add to Google Chrome, that will help you with your Etsy dropshipping journey. Here's exactly what I mean. The first tool is the AutoDS dropshipping helper extension. I already talked about this one. This one is gonna help you not only with your product research, where you can search multiple suppliers for products under one search field, but it'll also help you import your products to your store, the one-click importer, the bulk importer. It also comes with a really easy to use address copier when an order comes in from any one of your customers and so much more on top of that. So we've got a link to that, of course, in the cheat sheet. Besides that, you also have Etsy Hunt. So Etsy Hunt is a great tool that you can use that will help you with your product research. I'm not gonna go too deep into it. You have the link to it once again. And then you have two more tools. One is called Toolsy, which will help you rank higher in Etsy's search engine. So it's an SEO tool that will help your product pages rank even higher. And we've got Marketsy, which downloads all of your Etsy's customers' email addresses, which you can then use to send email marketing campaigns, which is another great marketing strategy that you can use today, which doesn't really cost any money because sending an email is free. The only thing that you'll need is customers to buy from your store. Then you'll have their email addresses and you can use this tool to export their emails so that you'll be able to send them email marketing campaigns. So you have once again the links to all those tools in the Etsy dropshipping cheat sheet, which you can get by simply commenting, hashtag Etsy 2023. Let me know what you learned from this video, what is your top takeaway. And once again, I'm more than happy to send you this cheat sheet with everything that I talked about in this video, all the resources, all the tools and all the links.


In this presentation, we will take a look at an internal control flowchart mapping out the processes and procedures related to internal controls. Starting off with the develop and understanding of internal controls by evaluating the design of controls, determining if the controls have been implemented. So that's the first thing we're going to do. We're going to say, hey, what are the internal controls? Could you give us the design of the internal controls? And then we want to determine whether or not the internal controls have been implemented. Next, we're going to document the understanding of the internal controls. So once we have that understanding, we of course, as auditors gathering evidence, will then document that understanding. Then we come to the question point. That's what this red box then means. So we have a question, a yes or no type of question. Does the auditor intend to rely on the controls? So at this point we have to say, do we rely on the controls or not? Now, if we're thinking about a publicly traded companies, we will probably be saying, yes, we're going to rely on the internal controls. If we cannot rely on the controls, we're in big trouble because we typically can't do enough substantive testing in the timeframe given to really support the full audit of a publicly traded company. However, if we have something less than a publicly traded company, it may may well be the case that we don't intend to fully trust or rely on the internal controls. And therefore we're going to do more substantive testing. So remember, at this point, publicly traded company, are we going to rely on the internal controls? We hoped we can at this point or else we're going to have to take into consideration what we're going to do going forward, whether or not we can basically finish the audit within the scope of it. If we're talking about smaller company, we may say no. And in that case, we're going to do more substantive testing. So you can imagine if we have a smaller company, we're going to say, okay, this internal controls aren't something that we can completely rely on. What are we going to do then? We're going to do a substantive strategy, meaning we're going to set control risk at the max. We're going to say control risk is high, meaning there's a high risk that the internal control set up by the organization by the business will not detect a material misstatement. And therefore we need to do more testing on the substantive testing side. So what are we going to do? We're going to increase the amount of the substantive testing instead of wasting our time or going further thinking about testing the internal controls, which we've determined not to be sufficient and therefore not something that we rely on.


Hello and welcome once again to the rugged rockhound today. I'm back out where I was Not long ago. I parked on that hill remember and I just walked up that and then I got out of here before a big rainstorm came and Hit so yeah, I'm glad to be back out here, and I'm here with Eric So he's gonna show me exactly where he was finding back lights further up So I hadn't gotten up that far yet to where the back lights occur So that explains why I hadn't seen any yet But Eric's a pro here, so he knows where to go and it looks like we have a wildfire out there Probably started up today That's too bad. Oh Well, so we're gonna go look for some back lights up there, and hopefully we'll find some really cool specimens Let's get up there. Oh just in case you need it. Here's the GPS coordinates to this location Which I gave on the last time I was out here. I didn't film anything when I was down there is mostly stuff We'd already seen before you can see where we parked out there so you walk up the ravine you can see how far you kind of have to come up the hill and Looking for I'm thinking this stuff. So Eric went around the other side He kind of gave me a rough idea of where we're at, but you're getting the right stuff when you start seeing these shells you can see the impressions of shell fossils here for the back of lights I think That looks like the right shape for a back light Yep That's a big section of a back light So remember I told you there are these long cones. That's just a segment of it and let me put the Other lens on all right got the other lens on let's see if we can see some of the structure in this that you typically get with back lights I Not seeing it so much in that one. Ah, I think I see another segment up here Looks right Yes Their segment right there What's this? Another segment What's nice is if you can find right where it's coming out Dig in a little bit and then you can hopefully get multiple segments That you can fit back together and maybe produce a nice long one of these so Yeah, this looks like the layer we want All right, let's get into it a bit. So there we go I moved some of the dirt and there you can see another segment of it There's more of the back light continuing down in there. So we'll just start pulling it out And I want to check and see if there's any segments maybe down here. I got buried Just in case Okay All right, so I'll dig into here and start pulling it out. Oh It's a tiny segment of it All right Here's the next segment. Oh, there you go So you see that structure right there? It's kind of got this wavy up and down that's indicative of one of these Okay, we're gonna get in towards the end of the cone here and the end of the cone usually is just shattered to pieces Hey, there's the impression of where it used to be Yeah, I see Now you're not really seeing anything So these are all pieces of the same one. I don't know if that is because that was found further down That could be from some melds Still really cool and there's where it came out of Here's this bell night that I was able to piece together at least that much backlight So I was down below that hill. I've come up Fair fair bit further because Eric said to come up and over around the side. So I'm up here and Hello There are little pieces of backlight everywhere You should be able to see someone Segment there segment segment Segment all through this lots of little ones cool There's this one you can still see most of the pieces kind of hugging each other Really cool. What do we have here? So that structure looks like it the end segment of one That one almost looks coiled Like an ammonite. So they usually were they originally were nice and straight and then over over time Through through history. They started to coil their shells until they became ammonites So maybe that's a little bit of a coil going there. Oh back to this one to extract it Nice looks like we're gonna get a pretty long one here. Oh, look at that I'm not sure if this is all part of the one continuous piece or if it's a couple different ones Look at that. I'm gonna have to use a handbag. Just dig it out by hand All this clay. Look at all those pieces Yeah, I think we got a couple different ones here But it'll be fun to try and piece them Some of them back together It's just curved Almost like a burrow So when I'm digging up a burrow That would be very sad. There we got the end of that one Huh Okay, well We may have something there We'll take it back and see what we can piece back together and see If it's something So here is the large coral pieced together as much as I could Just kind of show the whole thing put all together and they're playing some music over there There you go. Here's one of the oyster shells. It's pretty big Pretty cool That is definitely not a bell knight that looks like some branching coral It could also be a burrow track, but it looks more like a coral to me So yeah, we're getting some interference in here with some of these being corals Make kind of hard to spot the bell knights or back lights Look at that some really nice little spherical balls. These might be like You know like a little bit of something that got rolled by the waves into this shape They're cool So this was a neat little area There's a lot of interference here with with the corals and shells and whatever else is going on here And it seems like the the back lights tend to be kind of small here that bigger one I found was further down that way and I believe Eric's on the other side of that hill So I think I'm gonna head down and kind of go around that hill So I can meet up with him. Maybe he's in a spot where we can get some bigger ones And I wonder, you know, the layers can be very different Maybe there's a certain layer where you get the bigger ones. I don't know Well as it turns out Eric had been going around that side of the hill Why come they coming around this side and we just missed each other. He was just over there So that's where I was just up there decided to come further down because when I was coming up That's where I found the bigger one and up the here is mostly smaller ones Anyways, I was coming down. I found this kind of nice little example of here's the bell knight right here You can see a little bit of the ridges along the side and here's the rocket stuck in So that was nice just kind of an this upper section right here and there's the rest of the rock Looks like it kind of got fused together Here's a nice little piece of the coral So yeah, there is a lot of coral in here It's very hard to see the Back of lights because of so much coral We've found several with shapes like this that we're gonna probably try and cut and see if there's anything in them He found a tip. That's really cool. It might be the tip of the coral Really cool though Eric just found this cool piece of coral It's nice And a cool little piece. It looks like it's probably just shells at an angle, but it looks really cool After getting a bunch of little stuff We decided to come back down where I found the big one and he just pulled that nice piece out right there That's a really good one. Maybe there's more in there Hopefully it's not just a single loose piece Well, there you go, that's a nice piece though Eric found that up there and look what I just found on here. It's a piece of enamel. Oh, I'm slipping Very slick here. All right, let me get some better footing Okay, found this part of an ammonite You can see the structure right there. Definitely an ammonite and I just pulled out here. Let's see if there's more in here Or does it fall from up here? All right, I don't see any more so it it came out from somewhere Cool. Well, that's already some really good stuff. Let's just dig into it Here's that half an ammonite all pieced together. It's pretty cool So right where Eric had been digging and then he walked away He had pulled that out and missed it That's all right.  There could be several inside of this stuff here So I've been digging for a bit Pulled out this piece You can see the piece of it Coming out right there, and then that's just the Sorry, let me get a closer You can see it coming out of there And here's another segment of it Cool. Well, I was just digging into the dirt and I exposed that one. Oh Piece of it broke off It's a segment Aha just found one sticking out of the wall right there and see it right there Let's pull this thing out Unfortunately, that's about all that came out of it. There was another smaller piece. That was it. Oh And another one in the wall So I got this segment out and There continues right there. Hopefully you can see that There you can see it in segments going back into the rock like that You know the sun is setting It's time to get going So I got what I could out of that one So you can see where we're parked down there So we just kind of came up this wash right here and then came up this bigger hill to that outcropping right there Yeah Let's head back So I decided to just show everything I managed to piece together So here's that large coral. This is as much of it as I was able to get together Or a few pieces I couldn't figure out. This was a smaller coral that was coming out And then we just a teeny teeny piece that probably came off as something somewhere The Ammonite Partial and then these Bellam nights. That's how much I was able to piece back together Not too bad And we're back at the vehicle. This was a good spot some nice stuff Obviously the back of lights are what you come out here for and we got a good spot where they're quite a few and that was cool To find that one half of an amite So you can find those they're probably pretty few and far between Anyway, now, you know where it is. So I hope you enjoyed until next time. Remember There is treasure everywhere