THE SOUTHERN CALIFORNIA UPLIFT AND ASSOCIATED EARTHQUAKES

Southern California earthquakes greater than or equal to M5.5 during t he period 1955/01/01-1994/01/17 were concentrated along or adjacent to the south flank of the southern California uplift, as defined both at its culmination and following its partial collapse. Spatial clusterin g of these earthquakes within three more-or-less distinct groups sugge sts either gaps along the south flank that were previously filled or a re yet to be filled. Nearly all of the indicated earthquakes accompani ed or followed partial collapse of the uplift, and seismic activity wi thin this regime seems to have been increasing through at least 1994/0 1/17.