Seismic, Geological, and Coastal Visualizations of the San Diego Region
The SIO Visualization Center was awarded a grant from the Rose-Miah Fund as part of the science and technology competitive grant opportunities from The San Diego Foundation. With this funding, we are working with scientists at Scripps who conduct research in the San Diego region to direct our resources toward engineering 3D visualizations for the respective projects.
Atul Nayak, Debi Kilb, Leah Hogarth (SIO Graduate Student), Danny Brothers (SIO Graduate Student), Graham Kent, and Karen Felzer (USGS collaborator).
We examine two unusual events that followed the MW 5.2 earthquake near the town of Anza, California, on June 12, 2005. (1) Although the mainshock fault was only several kilometers long, aftershocks stretched for at least 50 km along the San Jacinto Fault zone; and (2) There was a MW 4.9 earthquake 4 days later and 72 km away, near the town of Yucaipa. We test the hypotheses that the extended Anza aftershocks were triggered by aseismic slip that followed the mainshock (Agnew and Wyatt, 2005) and that the close space-time proximity of the Anza and Yucaipa earthquakes was a coincidence.
The SIO Visualization Center collaborated with researchers involved in building the cyberinfrastructure for the NSF Ocean Observatories Initiative and produced graphics and animations that describe the instrument networks and the design of new mooring platforms.
In preparation for a meeting of the California Ocean Protection Council, the SIO Visualization Center developed a movie integrating draped satellite imagery, recently acquired LIDAR data, and projected changes in sea level according to various ocean-observing authorities, which would be presented at the meeting by Director of Scripps, Dr. Tony Haymet. The movie demonstrated the possible effects of the general trend in rising sea levels and ice cap melting on the coastal regions along the San Diego County.
We collaborated with researchers at the California Institute of Telecommunications and Information Technology (Calit2) and the Center for Earth Observations and Applications (CEOA) to design and deploy the ‘Mobile Interactive Imaging Multi-display Environment’ (MiniMe) system. The MiniMe comprises of a cluster of Apple Mac Mini computers and a grid of 15 Dell 24” monitors. Atul Nayak, the principal architect of this system collaborated with Greg Dawe, Calit2 to design the mounting solution to make the system portable. Nayak and Dane Samilo worked on porting various software suites (SAGE and COVISE) to the Mac OS X platform for use on the MiniMe and related cluster computing tasks. We continue to develop tools required for scientists to use this unique display system.
The SIO Visualization Center is producing visualizations for the Southern California Ocean Observing System (SCCOOS), an organization that aims to synthesize its observations into products that will provide a scientific basis for evaluating and improving management and guardianship of, and response to the ocean environment and its resources. The SIO VizCenter contributes high resolution interactive 3D visualizations of Southern California's coastal region and modelling of various sensors in use by SCCOOS.
A high-resolution CHIRP survey reveals shore-parallel variations in the Holocene sediment thickness offshore La Jolla, California. Sediment thicknesses decrease from greater than 20 m in the south near Scripps Canyon to zero in the north approaching Torrey Pines. In addition to the south to north variation in sediment thickness, the transgressive surface observed in seismic lines shoals from Scripps Canyon to the north. Despite these dramatic shore-parallel subsurface changes, the nearshore bathymetry exhibits little to no change along strike. A left jog (i.e., a constraining bend) along the Rose Canyon Fault causes local uplift in the region and appears to explain the northward shoaling of the transgressive surface, the decrease in relief on the transgressive surface away from the left jog, and the Holocene sediment thickness variation. This tectonic deformation is shore parallel, and thus the accommodation can be separated into its tectonic and eustatic components.
We study the temporal behavior of the initial part of the 31 October 2001 ML 5.1 aftershock sequence in southern California. This sequence occurred directly below the broadband ANZA seismic network, which recorded continuous waveform data at 13 azimuthally well-distributed stations about the study region (7 had epicentral distances < 20 km). Of the 608 aftershocks (0 < ML < ~2.8) in the initial 2-hours of this sequence, the initial 5 aftershocks were only identifiable at stations within 30 km. Using a cluster of 200 representative aftershocks, we track the maximum seismogram amplitude versus earthquake magnitude.
Examination of the Temporal Lag Between the 31 October 2001 Anza, California, ML 5.1 Mainshock and the First Aftershocks Recorded by the Anza Seismic Network
We study the temporal behavior of the initial part of the 31 October 2001 ML 5.1 aftershock sequence in southern California. This sequence occurred directly below the broadband ANZA seismic network, which recorded continuous waveform data at 13 azimuthally well-distributed stations about the study region (7 had epicentral distances < 20 km). Of the 608 aftershocks (0 < ML < ~2.8) in the initial 2-hours of this sequence, the initial 5 aftershocks were only identifiable at stations within 30 km. Using a cluster of 200 representative aftershocks, we track the maximum seismogram amplitude versus earthquake magnitude. This relationship helps us quantify the visibility of aftershocks within the mainshock coda and assess our detection capabilities.
Posters and Publications
Kilb, D., V. G. Martinov, and F. L. Vernon. "Aftershock Detection Thresholds as a Function of Time: Results from the ANZA Seismic Network following the 31 October 2001 ML 5.1 Anza California Earthquake." Bulletin of the Seismological Society of America; June 2007; v. 97; no. 3; p. 780-792; DOI: 10.1785/0120060116
Orcutt, J., J. Berger, and J. Halkyard. "The NSF Ocean Observatories Initiative Global Scale Observatory: Expandable Draft Platform." Eos Trans. AGU, 88(23), Jt. Assem. Suppl., Abstract OS21A-08
Brothers, D., G. Seitz, P. Williams, N. Driscoll, G. Kent. "Fault History and Architecture of the Southernmost San Andreas Fault and Brawley Seismic Zone: New Constraints from CHIRP Data Acquired in the Salton Sea." AGU, 2006.
Joint Oceanographic Institutions (JOI), Inc., has selected UC San Diego to design and construct information technology and networking for the Ocean Observatories Initiative (OOI). The initial $29 million Cyberinfrastructure (CI) award is for six years, and total funding may reach more than $42 million over the course of the planned 11-year project.The SIO Visualization Center will actively contribute to the CI project in terms of visualization pipeline design, 3D modeling and animation of ocean studies-related data and illustrations and graphics for education and public awareness.