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Coseismic displacements: 1992 Landers, California, earthquake

April 9, 1993

The rupture associated with the 1992 Landers earthquake (Ms = 7.5) extended along the west edge of a 60 × 50 km trilateration network that had been surveyed two months before the earthquake and was resurveyed a month after it. The coseismic displacement field within the network was calculated from the changes observed in the trilateration network supplemented by the displacements measured at four GPS stations and other less timely trilateration measurements. Stations near the rupture were displaced by as much as 3 m. The observed changes are reproduced reasonably well by dislocation modeling in which the Landers rupture is represented by 8 vertical fault segments, each extending from the surface to 9 km depth. Two additional segments represent the Big Bear and Eureka Peak faults. The average modeled right-lateral slip on the Landers rupture is about 5 m. However, the residuals for the best-fit slip distribution are about four times greater than expected from measurement error. Given that uncertainty, a broad range of slip models furnish acceptable fits to the data. The large residuals are attributed to inelastic deformation (principally sympathetic slip on numerous unmodeled faults) within the fault blocks assumed to be elastic in the model.

Publication Year 1993
Title Coseismic displacements: 1992 Landers, California, earthquake
DOI 10.1029/93GL00446
Authors M. H. Murray, J. C. Savage, M. Lisowski, W.K. Gross
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Index ID 70187458
Record Source USGS Publications Warehouse