We have relocated over 8600 earthquakes occurring between 1964 and 1999 at depths >25 km within ∼100 km of Anchorage, Alaska, using the double- difference technique. The relocated seismicity reveals important details of the subducting Pacific plate and Yakutat blocks including clustering of seismicity within the Pacific plate mantle, northeast- and northwest-striking near-vertical faults within the Pacific plate crust, and a region of intense deformation associated with the southwestern edge of the Yakutat block. Stress analyses from the direct inversion of first- motion data and from inversion of focal mechanisms for 713 events indicates a rotation of the maximum compressive stress direction from a trench parallel direction (northeast) in the southwestern portion of the study area to an east–west direction near the southwestern edge of the Yakutat block located just north of Anchorage. Regions of the Pacific plate mantle that produced Mw >6.4 earthquakes in 1934 and 1954 continue to be seismically active.

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