Slow Earthquakes and Nonvolcanic Tremor

Nonvolcanic tremor is observed in close association with geodetically observed slow-slip events in subduction zones. Accumulating evidence points to these events as members of a family of slow earthquakes that occur as shear slip on the downdip extensions of fault zones in a regime that is transitional between a frictionally locked region above and a freely slipping region below. By virtue of their locations and their properties, slow earthquakes are certain to provide new insights into the behavior of earthquakes and faulting and into the hazard they embody.