Project Abstract
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The April 4, 2010, .2$ El Mayor-Cucapah earthquake on the
US-Mexico border was the largest earthquake to strike Southern
California in the last 18 years. Shortly after the earthquake teams
from SIO and UCR, in collaboration with colleagues from CICESE
(Mexico) went to the field to conduct campaign GPS measurements to
obtain coseismic offsets and establish a baseline for postseismic
surveys. Continuous GPS coverage is reasonably good North of the
US-Mexico border, but very poor to the South, so campaign GPS
measurements are crucial for constraining the coseismic model, as well
as characterizing the postseismic deformation. An earthquake of this
size is expected generate a robust postseismic deformation transient,
as the continuous and preliminary campaign GPS data already indicate.
We propose to continue our campaign GPS measurements to capture
time-dependent deformation following the El Mayor-Cucapah earthquake.
The proposed research will focus on the campaign GPS data collection.
The proposed observations, along with other available geodetic data,
will be subsequently used to study the time-dependent response of the
Earth to coseismic stress changes, and test the existing hypotheses of
postseismic relaxation.
We will conduct at least 2 campaigns in 6-month intervals to ensure
that we capture the spatiotemporal evolution of the postseismic
velocity field (the survey frequency may be adjusted based on the
observed deformation rates). Each survey will involve two teams from
SIO (3 people each), one team from UCR (2 people), and collaborators
from CICESE (at no cost to this proposal). Fialko and Sandwell will be
leading the SIO field teams. The surveys will be conducted using the
SIO and UCR instrument pools. |
