Seismicity decreases with depth because elevated confining pressure prevents frictional sliding of faults. However, seismicity tends to increase with depth in the mantle transition zone (depths of 410−600km). It has been believed that pressure-induced phase transitions of olivine in the "cold" subducted slabs is the cause of high seismicity in the mantle transition zone.

Seismicity decreases with depth because elevated confining pressure prevents frictional sliding of faults. However, seismicity tends to increase with depth in the mantle transition zone (depths of 410−600km). It has been believed that pressure-induced phase transitions of olivine in the “cold” subducted slabs is the cause of high seismicity in the mantle transition zone.

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