We use time-domain pulse widths to estimate static stress drops for 279 M L 2.5 to 4.0 aftershocks of the 17 January 1994, M w 6.7 Northridge, California, earthquake. The stress drops obtained range from 0.02 to 40 bars, with a log average of 0.75 bar. Error bars computed for our estimates are typically a factor of 5, indicating that the three order of magnitude scatter in stress drops is not s...