We recovered 52 timed analog accelerograms from 25 aftershocks of
the 1979 Imperial Valley earthquake, between 3:33p.m. P.d.t. October
16 and 5:43 a.m. October 31. The largest aftershock that we
recorded (M_L =4.9) occurred at 4:16p.m. October 16. This aftershock
triggered eight accelerographs; preliminary estimates of epicentral
distance range from 7 to 35 km. The data from this aftershock may be
useful for study of both source and wave-propagation phenomena in
the Imperial Valley