Fault Slip Sensorsand DamageMap:

GPS in Rapid EarthquakeResponse Systems

Ken Hudnut

USGS, Pasadena

San Andreas fault 35 mm/yr slip rate;

>70% of plate motion 1685, 1857 eq’s

SoCal is now well ‘wired’

Likely source of most future ‘Big Ones’

Fault physics experiment GPS/INS in near-field ALSM & DG scan ‘net’

Great place to test EEW

Build “zipper” arrays Cholame - Simmler Coachella Valley

Lone Juniper Ranch and Frazier Park High School

First prototype GPS fault slip sensor; up to 10 Hz (Hudnut et al., 2002)

Spans the San Andreas fault near Gorman, California

San Andreas - place two betsboth ~120 km from Los Angeles (LA)

Coachella Valleysegment is ~60 kmto San Bernardino

San Andreas - instrument majorlifeline infrastructure crossings

•Satellite

•Telemetry

•Internet

SENSOR PACKAGE

-Accelerometer-Tiltmeter-GPS sensor

REAL-TIME DAMAGE ASSESSMENT

Courtesy ofErdal Safak (USGS)

Factor Building at UCLAPrototype for DamageMap

PI’s Erdal Safak, Monical Kohler and Paul Davis

Another technological advancefor rapid earthquake

information message delivery

Cell phones with GPS open possibility of ‘smart’ SMS real-time warning targeted to at-risk mobile users (outdoors) or mobile platforms (e.g., while in their cars)

[currently not feasible due to power requirements, if GPS is on all the time]

Maps2MEFutureRoads

Summary Slip sensor concept is to augment regional seismic coverage - one part of an

overall EEW system that is primarily using a very different approach

Measure slip directly - don’t need to know anything else - ‘quick & easy’

High risk deployment strategy tuned to rare pay-off in extreme events

Robust earthquake early warning system design obtain more accurate displacement observations new instrumentation for dynamic and static displacement address

deficiencies due to double-integration of accelerometer records

Same R&D effort as for DamageMap instrumentation - now under way with USGS Venture Capital and ANSS start-up funds, but major funding and long-term support for implementation has not yet been identified