Benioff Zone

The second zone that can produce earthquakes is the deep Benioff zone. This is located anywhere from 30 to 90 kilometers below the earth. You may know this as the area from which the Nisqually quake came. This is an area that is farther along in the subduction of the Juan de Fuca Plate, it is just a little deeper because it is subducting. In this area, the minerals begin to undergo a change in their configuration. During this morphing of minerals, the volume of the rocks begin to change and get smaller. As this occurs, earthquakes are likely to be triggered.

The earthquakes that occur here are fairly deep, which means they produce less of an impact by the time they reach the surface, not creating as much damage as an earthquake that occurs near the surface. The magnitude of the quakes that can occur here can reach up to just over a 7.0 on the Richter scale, perhaps even up to a 7.5.

To learn more about the Benioff Zone, click here.

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