Three earthquakes with ML ≥ 6.0 occurred near Mammoth Lakes, California on May 25, 1980 (ML = 6.1 at 1633 UTC, ML = 6.0 at 1649, and ML = 6.1 at 1944) followed by a ML = 6.2 shock on May 27 (1450 UTC) (Urhammer and Ferguson, 1980). The U.S. Geological Survey responded by undertaking an aftershock study using portable digital event recording seismographs. Our main goal was to get unclipped recordings of one or more large aftershocks.