The project I will be doing, under the supervision of Prof. Duncan Agnew and Dr. Frank Wyatt (SIO), will be to measure the motion of the Earth's surface at several points in Southern California, using data from the Global Positioning System (GPS) satellites. The purpose of making these measurements is to understand better how the active faults of this region, the source of its earthquakes, behave.
The project will include:
Collection of data at various locations, using the GPS receivers owned by UCSD. These locations will be chosen to be ones at which data has alreayd been collected (see below) to look for changes in the rate of motion.
Data analysis.
The raw data do not provide the information needed until
they have been processed together with other data collected
by the global GPS tracking network. Making the best use of the data
involves skill in using the analysis programs, the acquiring of
which will require some effort. I will be learning how to operate
the GAMIT program, which is infinitely complex.
Interpretation.
Once the data have been analyzed to produce the positions of
the points observed, it will be necessary to compare these
with past observations and interpret the results in terms of
models of fault motion in the area.
The specific projects to be pursued are:
Motion in the Salton Sea area.
To test other measurements being made along the San Andreas fault,
it is desirable to repeat earlier measurements made around the
Salton Sea (from 1973 on). Comparison of new measurements with these
earlier ones will show whether or not the crustal motion has been
steady, or has fluctuated with time over the past few years (which
have seen several large earthquakes).
Continuous GPS.
Since 1991 a 10-km baseline has been measured daily, using GPS,
near the San Jacinto Fault. Analysis of these data will provide
interesting results on the response of this fault to large
earthquakes, and on the noise level of these measurements.
Monument stability.
I have been making high-precision measurements between several
types of geodetic monuments to see how stably they are attached
to the soil. This work will be continued, and combined with GPS
measurements.