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National Aeronautics and National Aeronautics and Space AdministrationSpace Administration
High-definition Images Reveal Changes on Many Scales
• NASA radar reveals local surprises. . .
. . .and troubling fault motions 60 km north
• Precise images are adding realism to crustal models and forecasts
• UAVSAR blanketing California danger zones with change-detection images
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National Aeronautics and National Aeronautics and Space AdministrationSpace Administration
NASA Radar (UAVSAR) Imaging Quake Borderland and Beyond
Early image samples from UAVSAR Project, Scott HensleyOval indicates a region of triggered fault slip 2
National Aeronautics and National Aeronautics and Space AdministrationSpace Administration
Quake Triggers Responses on Key Faults
>Mw 2.0 Earthquakes (Apr-Dec 2010, orange dots) from the ANSS Worldwide Earthquake Catalog, Advanced National Seismic System
Fault traces from Southern California Earthquake Center, Uniform California Earthquake Rupture Forecast (UCERF-2), Edward H. Field and coworkers.
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• Elsinore fault extends into Los Angeles
• San Jacinto fault reaches to San Bernardino
• Full-length ruptures must be considered: damaging earthquakes
National Aeronautics and National Aeronautics and Space AdministrationSpace Administration
UAVSAR Images Slip 60 Km North of Earthquake
• Changes from 24 April 2009 to 13 April 2010
• Chiefly due to earthquake in Baja (El Mayor-Cucapah)
• “Creases” resemble fault slip 4
National Aeronautics and National Aeronautics and Space AdministrationSpace Administration
Imaged Slip Matches San Jacinto Fault Lines
• Left trace: Borrego Mountain Earthquake (1968, Mw 6.5); Right trace, top: Elmore Ranch Earthquake (1987, Mw 6.2); Right trace, bottom: Superstition Hills Earthquake (1987, Mw 6.6)
• Fresh slip on these faults verified in the field (Treiman)
• Signals stress transfer north into San Jacinto fault system; ripe for a damaging earthquake?
Fault traces (red) from USGS Earthquake Hazards Program
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Scale:20 km
National Aeronautics and National Aeronautics and Space AdministrationSpace Administration
Fault Precision Drives Hazard Simulations -- Virtual California
Virtual California faults, John Rundle and coworkers (UC Davis)
• Part of NASA QuakeSim project, which develops earthquake simulations and resources.
• Computer simulation: A 100,000 year virtual history of earthquakes, movies
• Addresses important hazard questions: how likely is a San Jacinto fault full/partial rupture?
• Relies on real fault information over wide areas, as radar imaging provides.
• Produces scores of large Baja virtual earthquakes (at right):
-- easy to find ones followed by damaging earthquakes to the north (3-30 years later). 6
National Aeronautics and National Aeronautics and Space AdministrationSpace Administration
Regular UAVSAR Imaging Blankets California’s Danger Zones
• Flight plans cover major faults,
including Elsinore, San Jacinto,
San Andreas every six months
detecting any changes.
• Earthquakes receive extra coverage
• Standing out instantly:
quakes, creeping faults.
• Within a few years:
the slow motions of major faults.
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National Aeronautics and National Aeronautics and Space AdministrationSpace Administration
Radar Imaging Enables Fresh Ways of Doing Earthquake Science
• Unprecedented complexity revealed in rupture pattern in Baja.
• Geologists enabled to rapidly map emerging fault networks.
• Satellites cover the globe, UAVSAR blankets California danger zones, LiDAR provides stunning detail. Coming: DESDynI mission.
• Is key to improving hazard forecasts, tracking slow fault motions.
• Images signs of stress transfer threatening cities to north.
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