Real-Time InSAR Seismic Wave Imaging

65214 High-resolution imaging and characterization of seismic waves, particularly those due to nuclear tests, are needed as they propagate across the earth¿s surface. The information could be used to determine the event source location and depth, as well as its magnitude, and pertains to nuclear test ban treaty verification, seismology, and other scientific and national security applications. This project will use a Synthetic Aperture Radar (SAR) to image, in real time, the surface Rayleigh wave from a seismic event as it propagates outward from the event hypocenter. By interferometrically comparing this image to a later image of the same scene, a high-resolution picture of the structure of the seismic wave will be produced. In Phase I, two independent approaches were used to explore the parameter space of seismic waves relative to the operational characteristic of SAR imaging systems. The two approaches agreed well with one another and support the feasibility of real-time seismic imaging. Phase II has three related components: (1) a continuation of the theoretical analysis pursued in Phase I, (2) a physical experiment in which a large conventional explosion is imaged using airborne and spaceborne SAR systems, and (3) the development and delivery of a software package capable of analyzing and inverting real-time InSAR seismic data to source event characteristics such as bomb yield and event epicenter. In combination these components will support, demonstrate, and deliver the capability to image and analyze seismic events in progress with unprecendented precision. Commercial Applications and Other Benefits as described by the awardee: An InSAR seismic event imaging system should contribute substantially to nuclear test treaty verification as well as to several areas of study in solid earth geophysics that are relevant to seismic hazards mitigation and Earth structure determination.