Thursday, May 25, 2017

Here's a Hawaiian Mystery for You: Where Did These Circles Come From?

We were on a desolate plain on the south side of Kilauea Caldera on the Big Island exploring the ongoing volcanic activity. The smoking pit of Halemaumau Crater with her bubbling lake of molten lava was only a half mile or so north of us, so yes, we were in a closed area (but legally in this instance!).
Given that no part of the exposed Kilauea shield is older than about 1,000 years, it's almost needless to point out that this is a young geological landscape. You can see that a thick forest can be seen off in the distance, but only a few shrubs and spindly trees are present at our feet. I saw just a few bugs when I got on my hands and knees for a closer look at the gravel.
Circles occur in nature for plenty of reasons. I don't want to provide a list because this isn't a multiple-choice test: it's a thought question! Where did the circles come from?
The middle of the circles are composed of relatively uniform particles about 1-2 millimeters across. The intervening edges are made of larger unsorted fragments. As you can see in the pictures, there is sometimes a single rock in the middle of the rings, and sometimes there is a shrub.

A couple of other background information items: Kilauea is a broad shield volcano composed of thousands of basalt lava flows. It is highly active, and indeed there has been a non-stop eruption going on one place or another on Kilauea since the early 1980s, the longest sustained eruption in recorded history. The lava lake in Halemaumau has been active since 2008. One further point to consider...should we be seeing gravel here, so close to the summit of Kilauea?

So there you go: don't be afraid to speculate! Give us some ideas in the comments section...

Wednesday, May 24, 2017

A Flight Around the World's Highest Mountains: Mauna Kea and Mauna Loa

Mountains that make their own weather can be frustrating because...they make their own weather. High mountains in the path of consistent winds force air masses upwards, causing the water vapor within to condense, forming clouds and as often as not, rain. This is especially true around the tallest mountains on the planet.

I'm not talking about Mt. Everest in the Himalayas. It's tall of course, just over 29,000 feet above sea level. But if one measures from the base of the mountain on the sea floor, Mauna Loa and Mauna Kea on the Big Island of Hawai'i are around 32,000 feet high (Mauna Kea edges out Mauna Loa by about 120 feet). The two giants are nearly 14,000 feet above sea level, and they rise in the middle of the northeast Trade Winds of the Pacific Ocean. They are often clear for a few minutes in the early morning, but the clouds can build quickly, obscuring the view. During our field studies trip in 2016, we had been exploring for five days before the students even saw Mauna Loa at all.
I've been privileged to visit the Hawaiian Islands eight times now, and that means there've been a few chances to see the great shield volcanoes from above as I've arrived or departed from the islands, but none of them was like the scene that presented itself to me this morning. We had an early flight, and for once I was on the correct side of the plane (for the record, on flights out of Hilo you want to be on the left side of the plane). There were just a few clouds on the northeast side, but we flew through them and soon the entire north flank of Mauna Kea was spread out below.
These mountains are astoundingly big. They formed from hundreds of thousands of eruptions of non-viscous (easily flowing) streams of basaltic lava generated at a "hot spot" in the earth's mantle hundreds of miles beneath the surface. The outer lithosphere of the earth slides over the hot spot, carrying earlier-formed volcanoes to the northwest. Kauai, Maui, and Oahu were all once large shield volcanoes like Mauna Kea and Mauna Loa, but they have subsided and erosion has ripped into their flanks. Mauna Kea and Mauna Loa will eventually suffer the same fate, and in fact Mauna Kea hasn't erupted in several thousand years (a number of very expensive telescope dot its summit). Mauna Loa is still highly active, having erupted in 1984. I wouldn't be shocked if it erupted again tomorrow (which would be the karma of just having left the island).
Perhaps my favorite shot of all, the north flank of Mauna Kea
These mountains aren't just fascinating as geological entities. They are also biological refuges. There are hundreds if not thousands of rare and endemic species of plants and animals in the forests on the flanks of the mountains. There are few environments like these on the planet, a slope that climbs from beaches to tropical rainforests, temperate rainforests, high deserts, and alpine slopes. One can see from the patchwork of cleared forests on the flanks of the volcanoes that we have severely affected these unique environments in order to raise cattle and goats. Many species, especially birds, have been lost, and other are barely hanging on.
Three gigantic shields in one picture, Mauna Kea on the left, Mauna Loa in the center, and Hualapai on the right.

It was a fascinating flight around the summits of the world's highest mountains!

Sunday, May 21, 2017

The Most Desolate Place in the United States? The Mauna Loa Weather Observatory

If I seem to be missing in action, it would be because I've been stuck on planes and in airports on my way to the conference and field trips of the Cordilleran Section of the Geological Society of America. Just my luck that they happen to be meeting in Hawai'i this year. I mean really, it's my luck! I am so happy to be back on the islands. We had a spare day, so we did a bit of exploring, finding our way up Saddle Road and driving to the Mauna Loa Weather Observatory, which among other things has been measuring the carbon dioxide content of our atmosphere since the 1950s.
This picture is not tilted. That's the upper slope of Mauna Loa
This post is a bit different than some. It may usually seem that I am encouraging you to visit the places that I write about, but that's not necessarily the case today. Today's destination is something you really have to want to do. Why? Because it could quite possibly be the most desolate place in the United States. It's the road reaches the 11,000 foot level of Hawaii's biggest volcano. And it's no tourist destination. There are no facilities. You can't even visit the observatory itself. It's off limits. But if you want to see a landscape that may be the closest analog on Earth to a place like Mars, this may be the place.
The road begins near the summit of Saddle Road between Mauna Loa and Mauna Kea. Most visitors head north up Mauna Kea to the Onizuka Center for Astronomical Studies. It has bathrooms, a gift shop, telescope viewing at night and grand vistas by day. It's a welcoming place. And it's only a six mile drive. If you go south towards the Observatory, the single lane road travels 17 miles, and at about the 10,000 foot level, you leave all earthly life behind (at least it is well hidden). These are lava flows, many if not most less than a century old, and what life is possible at 11,000 feet keeps getting extinguished by hot lava. It is as desolate a place as I have ever seen.

Would you want to visit this barren blasted place? Perhaps. It depends on what you want to get out of a visit to the islands. If you are in stellar shape, the road's end is a trailhead for the shortest hiking access to the top of Mauna Loa nearly 3,000 feet higher (about 3.8 miles to the summit ridge and another 3 or so to the actual summit). It's a case of instant altitude sickness just waiting to happen. If you want to see one of the most unearthly places on Earth, it may be worth your time. If you haven't seen the important parts of Hawai'i Volcanoes National Park, then your precious time might be better spent on the south side of the gigantic mountain.

Speaking for myself, I was fascinated the whole way.

Wednesday, May 17, 2017

The Unsung Waterfalls of Yosemite Valley

Sentinel Falls (left) and unnamed fall (right)
Lower Sentinel Falls
Royal Arches Cascades
Staircase Falls
Staircase Falls from Curry Village


Monday, May 8, 2017



Friday, May 5, 2017



The Hawai'i That Was: A New Blog Series


The Hawai'i That Was: Why Should We Care?





























The Hawai'i That Was: The Final Refuge

Monday, May 1, 2017

The Hawai'i That Was: The Final Refuge


