san andreas m w 7.9 earthquake: slip at critical lifeline crossings shakeout scenario for southern...

San Andreas MW 7.9 Earthquake:Slip at Critical Lifeline Crossings ShakeOut scenario for southern California

Dr. Ken HudnutU.S. Geological Survey, Pasadena CA

Southern San Andreas Fault Evaluation (SoSAFE) Project Leader; Southern California Earthquake Center

San Andreas MW 7.9 Earthquake:Slip at Critical Lifeline Crossings ShakeOut scenario for southern California

Dr. Ken HudnutU.S. Geological Survey, Pasadena CA

Southern San Andreas Fault Evaluation (SoSAFE) Project Leader; Southern California Earthquake Center

U.S. Department of the InteriorU.S. Geological Survey

San Andreas fault• Most likely source of future ‘Big Ones’ (M > 7.5)• 35 mm/yr slip rate;

• >70% of relative NoAm - Pac plate motion• 1685, 1812, 1857 great earthquakes

• Big Bend compression• SoCal heavily ‘wired’ - seismic & GPS stations• GPS measures plate motion strain accumulation

and large earthquake displacements• ‘Natural laboratory’ to study earthquakes• B4 - imaged by high-resolution airborne LiDAR

Mw7.9 ‘ShakeOut’ Scenario (Nov. 2008)

• San Andreas ‘Really Big

One’ simulated earthquake

• Slip of 4.25 meters at Cajon

Pass (I-15); ~6.50 m at I-10

• Basic description sent out

via OES statewide and

announced at SoSAFE

workshop Jan. 9, 2007

• Developments needed:

– Earthquake Early Warning• Zipper array along fault

• Lifeline crossings

– Building Damage Assessment

• DamageMap

Credit: Nitin Gupta, OpenSHA & Ned Field, USGS

ShakeOut Scenario v.2 (Jan. 12, 2007)

• Uniform application of CGS ‘A-faults’ special report (Appendix A) slip rates & sections (Wills, Weldon and Bryant, in review for WGCEP)

• Unilateral from SE to NW• 1812 event ruptured to Burro

Flats• Features:

– sharp slip steps– ramp-ups and ramp-downs

near ends

• San Andreas dips considered (only one section dips in A-faults tables)

– References available through SoSAFE e-mails

thrusting& folding

18571857 18121812 16801680

20±310±316±322±628±7

Slip Rates:

"Good science, when applied in the way that the people of Alaska have done, made the difference between an emergency and a tragedy."

Charles Groat, Director, United States Geological Survey

Each day, the Trans-Alaska oil pipeline carries one million barrels of oil, about 17% of the domestic oil supply for the United States, valued at about $25 million. If the pipeline had ruptured during the 2002 Denali earthquake, the lost revenue and cost of repair and environmental cleanup would have been incalculable.

San Andreas - need to instrument majorlifeline infrastructure crossings

Cajon Pass I-15 Fault Crossing

Lone Juniper Ranch and Frazier Park High School

Prototype GPS fault slip sensor

Spans the San Andreas fault near Gorman, California

Need robust GPS at all key lifeline crossings

Desirable to include seismic with GPS

San Andreas - need to at least instrument major lifeline infrastructure crossings

No funding has yet been identified for an operational system

Proposal - zipper array for early warning and immediate finite-fault source for San Andreas and San Jacinto fault ‘Big Ones’

IOC - 36 quadrilaterals shown @ 30 km spacing (shown)FOC - 100 quads @ 10 km spacing ($5 M init. + $1 M/yr)

•Satellite

•Telemetry

•Internet

SENSOR PACKAGE

-Accelerometer-Tiltmeter-GPS sensor

REAL-TIME DAMAGE ASSESSMENT

Erdal Safak (USGS)

hundreds of buildingsmonitored in real-timefor earthquake and otherhazards (e.g., wind,acts of terrorism)

DamageMap

ShakeOut exercise - Nov. ‘08MW 7.9 earthquake scenario

Slip at Lifelines Fault CrossingsUSGS has the earthquake mandate and expertise, as well as a new SoCal multi-hazards initiative - let’s work together

Funds for improved monitoring of the San Andreas fault system - and of buildings in LA area - are greatly needed

Kenneth W. Hudnut, Ph.D.

Geophysicist

U. S. Geological Survey

525 S. Wilson Ave.

Pasadena CA 91106

hudnut@usgs.gov

Office: (626)583-7232

Cell: (626)672-6295