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>Return to Research
Locating small earthquakes using InSAR
30 Locations of Selected Small Earthquakes in the Zagros Mountains, R. B. Lohman, M. Simons, G-cubed, Volume 6, Number 1, Q03001, doi:10.1029/2004GC000849, March 2005.[PDF]
We are using InSAR and seismic data to develop an incomplete catalog of well-constrained hypocenters and mechanisms for a selected set of small shallow earthquakes. In particular, we are interested in earthquakes that can be reasonably modeled as point sources or simple planar sources with relatively simple source time functions. The only limitation to this effort is that any particular event must generate surface deformation detectable with satellite InSAR. This limitation is a function of the size and depth of the earthquake, the number of interferograms available for stacking, and maintaining interferometric correlation. So far, we have considered events in the U.S., Iran and Chile (ref 13 and 30). Given the inherent tradeoffs with assumed seismic velocity structure, these earthquakes are typically difficult to study using seismology alone, with hypocentral depth being the most difficult parameter to infer. From a purely geophysical perspective, such a catalog of small earthquakes enters into our understanding of individual tectonic structures particularly in fold and thrust belts. By providing a suite of sources that do not need to be (and should not be) relocated, such a catalog could also be useful for both structural seismologist and those studying nearby large events with complex rupture patterns. Finally, such “calibration” events can provide useful information for those involved in Comprehensive Test Ban Treaty activities.
Stacked radar interferograms showing surface displacements induced by the 1992 M5.4 Little Skull Mountain (NV) earthquake. Dots and rectangles indicate different published models for this event. For more details, see ref 13.13 Location and mechanism of the Little Skull Mountain Earthquake as constrained by satellite radar interferometry and seismic waveform modeling, R. Lohman, M. Simons, and B. Savage, J. Geophys. Res., 107, 10.1029/2001JB000627, 2002. [PDF]
Mark Simons' Paper Collection: Entire paper including figures are all made available online (within the bounds of copyright restrictions).
