In Chile Chile, New Zealand and San Andreas.
1 The magnitude of an earthquake is a measured value of the earthquake size. 2  The magnitude is the same no matter where you are, or how strong or weak the shaking was in various locations. 3  The intensity of an earthquake is a measure of the shaking created by the earthquake, and this value does vary with location. 1 The deepest earthquakes typically occur at plate boundaries where the Earth”s crust is being subducted into the Earth’s mantle. 2  These occur as deep as 750 km (400 miles) below the surface. 3  Alaska is the most earthquake-prone state and one of the most seismically active regions in the world. Tectonic Plates and Plate Boundaries. The Earth’s outer shell, the lithosphere, consisting of the crust and uppermost mantle, is divided into a patchwork of large tectonic plates that move slowly relatively to each other. There are 7-8 major plates and many minor plates. 1. Convergent boundaries: where two plates are colliding. Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust. The denser plate is subducted underneath the less dense plate. The plate being forced under is eventually melted and destroyed. i. Earthquakes at a Plate Boundary. An earthquake is a sudden motion or trembling in the crust caused by the abrupt release of accumulated stress along a fault, a break in the Earth’s crust. The ‘Ring of Fire’ shows the position of the New Zealand continent within a zone of intense seismic activity around the Pacific Ocean. Earthquakes in New Zealand occur because we are located on the boundary of two of the world’s major tectonic plates – the Pacific Plate and the Australian Plate. These plates are colliding with huge force, causing one to slowly grind over, under or alongside the other. An earthquake is a sudden motion or trembling in the crust caused by the abrupt release of accumulated stress along a fault, a break in the Earth’s crust. The ‘Ring of Fire’ shows the position of the New Zealand continent within a zone of intense seismic activity around the Pacific Ocean. Time line of Earthquakes in Chile. Earthquakes in Chile. Chile is located on a tectonic plate boundary and a subduction zone called the Peru-Chile trench. A subduction zone is where the ocean crust slides under the continental margin which causes compressional deformation (mountain building), earthquakes and volcanoes. Earthquakes occur at any fault line, but the most destructive earthquakes happen at subduction zones. In fact, the largest earthquake of this century was in Valdivia Chile, on May 21st 1960. Siesmicity has shown us that Chile has continual earthquakes year in and year out, some much bigger than others. For example, the San Andreas Fault in California is a continental transform boundary. Along this boundary, frequent, shallow earthquakes occur (like the famous 1906 and 1989 San Francisco earthquakes), but there is little associated volcanic activity or topographic relief (see Figure 7). In general, plate boundaries are the scene of much geologic action-earthquakes, volcanoes, and dramatic topography such as mountain ranges like the Himalayas are all concentrated where two or more plates meet along a boundary. The surface where they slip is called the fault or fault plane. The location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicenter. Sometimes an earthquake has foreshocks. These are smaller earthquakes that happen in the same place as the larger earthquake that follows.  An earthquake (also known as a quake, tremor or temblor) is the perceptible shaking of the surface of the Earth, which can be violent enough to destroy major buildings and kill thousands of people. The severity of the shaking can range from barely felt to violent enough to toss people around. At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally volcanic activity. Map of the San Andreas Fault, showing relative motion. The San Andreas Fault is a continental transform fault that extends roughly 1300 km (810 miles) through California. It forms the tectonic boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip (horizontal). 
http://earthquake.usgs.gov/learn/facts.php http://www.gns.cri.nz/Home/Learning/Science-Topics/Earthquakes/Earthquakes-at-a-Plate-Boundary/Tectonic-Plates-and-Plate-Boundaries http://www.gns.cri.nz/Home/Learning/Science-Topics/Earthquakes/Earthquakes-at-a-Plate-Boundary http://www.gns.cri.nz/Home/Learning/Science-Topics/Earthquakes/Earthquakes-at-a-Plate-Boundary http://legacy.earlham.edu/~bieriir/earthquakes/ http://www.visionlearning.com/en/library/Earth-Science/6/Plates-Plate-Boundaries-and-Driving-Forces/66 http://earthquake.usgs.gov/learn/kids/eqscience.php https://en.wikipedia.org/wiki/Earthquake https://en.wikipedia.org/wiki/San_Andreas_Fault
where is a earthquake boundary located