Crustal deformation measurements contribute enormously to our understanding of tectonics, earthquakes, volcanism, and landslides by permitting us to see processes we cannot observe directly. They are used routinely to constrain the subsurface geometry of active faults, to infer the spatial distribution of coseismic slip, and to study the response of the elastic crust to magma intrusion preceding volcanic eruptions. These data are the primary means for recording aseismic processes such as afterslip, viscoelastic and poroelastic adjustments and silent earthquakes. Accurate measurements of inflationary doming and stretching of the crust help in the forecasting of volcanic activity. Similar data play an important role in quantifying the kinematics of active landslides.
Using modern information theory, the investigators have generalized persistent scatterer techniques for InSAR, a visual geodetic technique that permits detailed mapping of motion over wide areas and exposes complex deformation patterns. Their technique helps to find stable points in natural terrain which can be used as a network of fiducial points in otherwise poor-quality interferograms. This will help extend InSAR analysis to heavily vegitated areas. The investigators are applying their new techniques to the San Francisco Bay segment of the San Andreas Fault and Hayward Fault. Their obervations will help follow the earthquake cycle in more areas and may compliment geodetic measurement of volcanoes, as well as improve InSAR capabilities in many other applications.
The Broader Impacts of the project include adding more information to assess natural hazards, like earthquakes, volcanoes and landslides, in a variety of terrains, training of graduate students in these methods and making software and algorithms freely available to interested researchers.
