Project Abstract
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In recent years, the steadily increasing volume of GPS observations and freely-available SAR imagery has prompted calls from the community for a model of ground deformation that is consistent with both of these data types. Such products have been produced in the past, such as the Crustal Motion Map, which included contributions from campaign and continuous GPS data, as well as models of coseismic offsets. A growing number of research groups have versions of a secular model of motion at existing sites, as well as models of hydrologic loading/seasonal cycles. In Southern California, the density of GPS stations is high enough relative to the size of individual SAR frames to motivate consideration of how consistent secular models are between the two observation types.
The SCEC community, therefore, proposed the creation of a Community Geodetic Model (CGM), with the goal of developing a consensus model characterizing deformation in Southern California. Such a model could be used as input to efforts such as the Crustal Stress Model, aseismic transient detection, block modeling and characterization of long term slip rates along faults, the integration of geodesy into hazard maps, and an important record of interseismic deformation rates in the event of a large earth- quake in Southern California, facilitating later studies of the observed postseismic deformation and/or interactions with other faults. Here, we propose to explore a problem identified during the latest CGM workshop – the appropriate choice of metrics to use when comparing InSAR and GPS-based models of deformation. We ended up focusing further on atmospheric models used in correcting InSAR, and on ways to present 3D deformation fields generated from GPS and InSAR. |
