TECTONICS AND SEISMICITY OF THE SOUTHERN WASHINGTON CASCADE RANGE

Geophysical, geological, and seismicity data are combined to develop a transpressional strain model for the southern Washington Cascades reg ion. We use this model to explain oblique fold and fault systems, tran sverse faults, and a linear seismic zone just west of Mt. Rainier know n as the western Rainier zone. We also attempt to explain a concentrat ion of earthquakes that connects the northwest-trending Mount St. Hele ns seismic zone to the north-trending western Rainier zone. Our tecton ic model illustrates the pervasive effects of accretionary processes, combined with subsequent transpressive forces generated by oblique sub duction, on Eocene to present crustal processes, such as seismicity an d volcanism.