Earthquakes at subduction zones
- Most earthquakes take place within 70-100km of the Earth's surface. They are confined to the lithosphere (moving plate).
- Althouth the layers of Earth that lie below the lithosphere can allow seismic waves to pass through, these layers do not generate many earthquakes.
- Unusually deep earthquakes occur near the edges of some continents, particular around the Pacific Ocean. These deep earthquakes tend to deepen towards the interior of continents.
- Earthquakes occur most frequently at plate margins (rather than continetal margins)
Questions for thought
- Which colored circles represent deeper earthquakes, yellow or red?
- Are most earthquakes at midocean ridges relatively shallow or deep?
- Are most earthquakes under South America on the east or west sides of that continent?
- Do more earthquakes take place at the edges of continents or tectonic plates?
- Are the deepest earthquakes found nearest to the coast of South America or further inland?
- Why are there unusually deep earthquakes on the edges of the continents around the Pacific rim?
Research at SIO
© 2007 Earthguide at Scripps Institution of Oceanography.
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