Abstract

The fortuitous occurrences of the 1992 Landers and the 1999 Hector Mine earthquakes within a regional GPS network established during 1991 in the Mojave Desert allows assessment of earthquake-related deformation for both events. Annual and earthquake-response campaign-mode GPS observations record active deformation in the Mojave Desert over the past decade. We present new displacement fields for both the Landers earthquake and the Hector Mine earthquake, using corrections for well-established 1993 to 1999 velocities to provide robust estimates of coseismic displacement. Each displacement field is compared to a forward elastic dislocation model for the earthquake that integrates geologically and seismologically determined offsets along the Landers rupture and is then used to geodetically constrain an inversion for elastic dislocation. The geodetic data sets provide better resolution of moment magnitude for a given fault plane, and systematically underestimate seismologically determined Mw by 0.06 to 0.07. In addition, during the 1992 to 1999 time interval, the post-Landers earthquake velocities at stations within 40 km its surface rupture provide direct observations that support kinematic loading of the Hector Mine rupture plane. This observation substantiates predictions from recent viscoelastic models.

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