title: Deformation on nearby faults induced by the 1999 Hector Mine earthquake.
abstract: Interferometric Synthetic Aperture Radar observations of surface deformation due to the 1999 Hector Mine earthquake reveal motion on several nearby faults of the eastern California shear zone. We document both vertical and horizontal displacements of several millimeters to several centimeters across kilometer-wide zones centered on pre-existing faults. Portions of some faults experienced retrograde (that is, opposite to their long-term geologic slip) motion during or shortly after the earthquake. The observed deformation likely represents elastic response of compliant fault zones to the permanent co-seismic stress changes. The induced fault displacements imply decreases in the effective shear modulus within the kilometer-wide fault zones, indicating that the latter are mechanically distinct from the ambient crustal rocks.
authors.affiliation: Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA. fialko@radar.ucsd.edu
authors.forename: Yuri
authors.initials: Y
authors.lastname: Fialko
authors.forename: David
authors.initials: D
authors.lastname: Sandwell
authors.forename: Duncan
authors.initials: D
authors.lastname: Agnew
authors.forename: Mark
authors.initials: M
authors.lastname: Simons
authors.forename: Peter
authors.initials: P
authors.lastname: Shearer
authors.forename: Bernard
authors.initials: B
authors.lastname: Minster