Periodic Slow Earthquakes from the Cascadia Subduction Zone

Continuous geodetic measurements from convergent margins have shown that deep transient creep events can release large amounts of strain energy without detectable seismic shaking, and they are thus known as slow or silent earthquakes. Because subduction zones generate the largest earthquakes, seismic hazard assessment relies on understanding the degree to which slow earthquakes reduce the energy released by infrequent large earthquakes. We present data that indicate the periodicity of slow earthquakes in Cascadia and the current onset of such an event