San Andreas MW 7.9 Earthquake: Slip at Critical Lifeline Crossings ShakeOut scenario for southern California Dr. Ken Hudnut U.S. Geological Survey, Pasadena CA Southern San Andreas Fault Evaluation (SoSAFE) Project Leader; Southern California Earthquake Center U.S. Department of the Interior U.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 1857 1812 1680 thrusting & folding Slip Rates: 28±7 22±6 16±3 10±3 20±3

anticipated San Andreas "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. M 7.9 - similar to the anticipated San Andreas fault 'Big One'

San Andreas - need to instrument major lifeline infrastructure crossings L A

Cajon Pass I-15 Fault Crossing Need a real-time GPS array right here... need before (B4) and after imaging for rapid assessment of damage to lifeline infrastructure

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

Lifeline Crossing Points San Andreas - need to at least instrument major lifeline infrastructure crossings 0.0 m 4.2 m 4.25 m 3.3 m L A 6.5 m M 7.9 Eq. Scenario Slip at Lifeline Crossing Points 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’ L A IOC - 36 quadrilaterals shown @ 30 km spacing (shown) FOC - 100 quads @ 10 km spacing ($5 M init. + $1 M/yr)

DamageMap Erdal Safak (USGS) hundreds of buildings monitored in real-time for earthquake and other hazards (e.g., wind, acts of terrorism)

ShakeOut exercise - Nov. ‘08 MW 7 ShakeOut exercise - Nov. ‘08 MW 7.9 earthquake scenario Slip at Lifelines Fault Crossings USGS 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