InSAR reveals new insights into the behavior of seismically active faults in the western Basin and Range

摘要

Traditional field investigations of large surface rupturing earthquakes in the western Basin and Range led to many early insights into the structure and kinematics of active faulting processes. During the last decade, the application of interferometric synthetic aperture radar (InSAR) has now provided new spatially detailed ground deformation data that reveal additional insights into these processes. Four InSAR case history studies are presented that illustrate the enhanced level of structural-tectonic detail that InSAR can provide in characterizing Nevada earthquakes. 1) InSAR analysis and modeling of the 1994 Double Spring Flat earthquake (M 5.9) showed that the earthquake was produced by primary oblique-slip rupture on a NW-striking fault and was accompanied by triggered, conjugate faulting. 2) The 2008 Wells earthquake (M 6.0) was a normal faulting event on a previously unrecognized Holocene fault that produced 15-20 cm of dip-slip ground deformation as detected and modeled by InSAR. 3) The 2008 Reno-Mogul earthquake (M 4.7) is the smallest magnitude earthquake detected with the InSAR in the western Basin and Range. Elastic dislocation modeling of the InSAR data indicates that the event was produced by dextral slip on a new Walker Lane style strike-slip fault in the Reno basin. 4) InSAR data shows that the Central Nevada Seismic Belt continues to display ground deformation more than 50 years after the Dixie Valley-Fairview Peak earthquakes. Visco-elastic modeling has shown the InSAR detected deformation is related to post-seismic relaxation of the earth's crust.