Coseismic ground deformation due to an intraplate earthquake using synthetic aperture radar interferometry: The Mw6.1 Killari, India, earthquake of 29 September 1993

摘要

The M w 6.1 Killari earthquake of 29 September 1993 occurred in central India, an intraplate area of low historical seismicity resulting in 11,000 fatalities and causing devastation within a 15 km by 16 km region near the epicenter (18.01°N, 76.56°E). This earthquake occurred on a nearly east-west trending, ～45° south dipping reverse fault and is one of the few intraplate earthquakes to produce a primary surface rupture. Interferometric analysis of ERS-1 and ERS-2 synthetic aperture radar data reveals ground deformation attributable to the Killari earthquake. Modeling the earthquake as a dislocation in an elastic half-space points to reverse slip on a steep dipping fault though a planar fault does not fit the data well. Although severe temporal decorrelation effects prevent determination of all details of the ground deformation pattern, the analysis establishes that the coseismic deformation occurred over a region with dimensions of approximately 30 km by 20 km and suggests possible subsidence due to soil compaction within the meizoseismal area. Comparison of interferometric synthetic aperture radar measured to model-predicted deformation indicates that the fault ruptured by the Killari earthquake increased in steepness from ～45° near the ground surface to ～70° at a depth of ～6 km.