Interferometric Techniques to Monitor Crustal Strain and Deformation
Allison Jacobs
UC San Diego
amjacobs@ucsd.edu
Mentor: David Sandwell, UCSD
In this project, I have studied the crustal strain and deformation along two faults in South Eastern California using interferometric techniques. The two faults involved in this study are the San Andreas, particularly in the Mecca Hills and Indio area, and the Lavic Lake fault, site of the 1999 Hector Mine earthquake. Both of these areas of California are tectonically active, and therefore, scientists continually search for new and better ways to measure this crustal motion. Interferometry has become one of the newest types of monitoring systems because it provides more precise measurements of small-scale deformation compared to the current widespread system of using a relatively coarse distribution of GPS monitors. Working with David Sandwell at Scripps Institution of Oceanography, I am utilizing many of his interferometry resources to investigate several questions involved with crustal deformation: First, is interseismic strain concentrated with a 4 km region of the San Andreas fault, secondly, are there significant variations in the amount of strain along the San Andreas fault, and lastly, what type of co- and post-seismic displacement is seen in the Hector Mine area? These questions will mostly be answered by using archive and near-real-time interferometry. In the future, the formation of interferograms on a regular basis, especially of the Southern California area, will allow scientists to observe increasing rates of crustal strain and thus issue warnings of faults with high breakage (earthquake?) potential.
To answer my questions, I must first form the interferograms. One of our main goals is to make a near-real-time interferogram. By working at the Scripps Institution of Oceanography satellite ground station, I am on-site when the ERS-2 spacecraft flies along Tracks 127 (Hector Mine) and 356 (Mecca Hills) and transmits near-real-time synthetic aperture radar data (SAR) to the station. After each fly-over, I will extract a frame of data from the respective flight that matches a frame from the WInSAR (Western North America InSAR) data archive. Assuming all goes well, these two frames of data will be processed together to form a near-real-time interferogram. However, as science rarely goes as planned, the near-real-time data can be saved a made into an archived interferogram at a later time. In addition to the near-real-time interferograms, I am forming interferograms from archived data in order to add validity to my research.
Table of Contents
Interferometric Techniques to Monitor Crustal Strain and Deformation
Geometry of Synthetic Aperture Radar
Co-seismic Displacement along Lavic Lake Fault
Creep Assessments of San Andreas Fault