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Geodetic observations of the M 5.1 January 29, 1994 Northridge aftershock

Andrea Donnellan, & Frank H. Webb

Published 1998, SCEC Contribution #399

Geodetic observations of the January 29, 1994 M 5.1 aftershock of the Northridge earthquake are consistent with seismic solutions showing left-lateral oblique slip on a northeast striking steeply dipping fault. Thirty second solutions of the data from the station showing the maximum observed displacement (35 mm) indicate neither precursory nor immediate post-seismic motion to the aftershock. The aftershock does appear to be superimposed over the longer term Northridge post-seismic deformation field. Inversions of the data yield a potency of 2.6 ± 0.3 × 10−3km³ slightly higher than that determined by seismic methods. Combining the potency with estimates of rigidity from P- and S-wave velocities yields a moment that is consistent with seismic moment solutions.

Donnellan, A., & Webb, F. H. (1998). Geodetic observations of the M 5.1 January 29, 1994 Northridge aftershock. Geophysical Research Letters, 25(5), 667-670.