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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