Annual Meeting - SCEC.org

Poster Abstracts
DYNAMIC RUPTURE SIMULATION WITH A HIGH-ORDER DISCONTINUOUS GALERKIN METHOD ON
UNSTRUCTURED TETRAHEDRAL MESHES (B-053)
C. Pelties, J. de la Puente, J.-P. Ampuero, G. Brietzke, and M. Käser
We will present recent developments concerning the extensions of the arbitrary high-order derivative Discontinuous Galerkin
(ADER-DG) method to solve three dimensional dynamic rupture problems on unstructured tetrahedral meshes. First of all, we
verify our implementation by comparing results of the SCEC test case with other numerical methods. An important result of
the benchmark is that the ADER-DG method avoids spurious high-frequency contributions in the slip rate spectra and
therefore does not require artificial Kelvin-Voigt damping or a posteriori filtering of synthetic seismograms.
To demonstrate the capabilities of the high-order accurate ADER-DG scheme on unstructured meshes we use the 1992
Landers earthquake as an example. It represents a complex fault system including branching and six curved fault segments.
Furthermore, topography is respected in the discretized model to capture the surface waves correctly. Strong mesh coarsening
or refinement at areas of interest is applied to keep the computational costs feasible. Finally current problems and further
developments will be discussed.
USE OF INTEGRATED MASTER MULTISPECTRAL IMAGERY AND LIDAR DEM FOR ACTIVE FAULT
DETECTION AND EVALUATION (A-144)
F.G. Perez, W.A. Bryant, J.A. Treiman, C.R. Real, and S.J. Hook
Displacement caused by surface fault rupture associated with large earthquakes not only disrupts infrastructure and damages
natural and built environments, but also constitutes a life safety hazard. The California Geological Survey (CGS) has the
authority and responsibility, under the Alquist-Priolo Earthquake Fault Zoning Act, to identify and map active faults in
California for the purpose of surface rupture hazard identification and mitigation through regulatory zoning.
Mapping and evaluation of active faults is generally accomplished through conventional aerial photo interpretation and field
mapping, which rely on recognizing fault-related geomorphic features and juxtaposition of contrasting rocks, soil, and
geologic structure. Faults covered by vegetation or concealed by young alluvium will most likely not be detected by this
method. Furthermore, spatial accuracy of photo-interpreted fault traces is limited to the accuracy, scale, and method of
transfer to conventional topographic base maps, which generally lack the spatial accuracy of geolocated imagery.
The inherent limitations of conventional active fault mapping are expected to be overcome by using integrated MASTER and
LiDAR data. MASTER is a multispectral imagery with 50 spectral bands ranging from visible to thermal region of the
electromagnetic spectrum. LiDAR on the other hand is a laser-based technology with very high positional accuracy, sub-meter
resolution and capability to filter out vegetation. MASTER and LiDAR are integrated via data transformation/fusion and the
resulting fused imagery are utilized to interpret active faults through recognition of fault features associated with different
distinctive properties related to geology, drainage, vegetation, hydrology, thermal, anthropogenic, and topography. The
completeness and accuracy of the fault interpretation is gauged by overlaying it to a baseline data of previously mapped fault
traces.
The research study, supported by a NASA grant, evaluated a well-mapped, 26-km reach of the southern San Andreas Fault
Zone in the Antelope Valley near Palmdale.
IDENTIFYING AND LOCATING TECTONIC TREMOR BENEATH THE SAN ANDREAS FAULT NEAR
PARKFIELD, CA, WITH THE PASO ARRAY (B-047)
D. Peterson, C. Thurber, E. Montgomery-Brown, J. Brown, and D. Shelly
Tectonic tremor is a weak but persistent shaking of the Earth that was first discovered in subduction zones and later found
beneath the San Andreas Fault (SAF). Tremor events represent spasmodic slip on the deep extension of the SAF, occurring at a
depth of about 20-25 kilometers. Tremor occurs deeper than the nearby regular earthquakes, which can be found at maximum
depths of 12-15 kilometers. Tremor is characterized by bursts of low frequency and/or very low frequency earthquakes
(LFE/VLF) with dominant energy in the 1-10 Hz range. Tremor tells us about fault slip at depth in both space and time by
illuminating the fault down to about the base of the crust.
In the pursuit of deriving information about deep fault behavior and crustal structure, we are analyzing continuous data from
the previously untapped Parkfield Area Seismic Observatory (PASO) temporary array, operated in 2000-2002 and 2004-2006.
We started the identification process by correlating templates of known events from a nearby station array based on an
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