We present new seismic data for subduction of a 180-km-long segment of the Gorda plate beneath Cape Mendocino in northern California. The inclined seismic zone dips ∼10 to 11° in the direction S68°E for a length of 120 km to depths of 30 to 35 km, then steepens in dip to 25° and plunges to depths of at least 60 km. P-wave focal mechanisms of two earthquakes at depths of 30 and 58 km are consistent with downdip tension and imply that these events resulted from stresses within the slab and not from Gorda-North American plate interaction.

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First page of Evidence for a 180-km-long subducted slab beneath northern California
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