1. 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

2. 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

3. 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

4. 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 s
1857
1812
1680
thrusting
& folding
Slip Rates:
28±7
22±6
16±3
10±3
20±3

5. 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 similar to the
anticipated San Andreas
fault 'Big One'

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

7. 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

9. 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

10. 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

11. 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 30 km spacing (shown)
FOC km spacing ($5 M init. + $1 M/yr)

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

13. 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

14. Kenneth W. Hudnut, Ph.D.
Geophysicist
U. S. Geological Survey
525 S. Wilson Ave.
Pasadena CA
Office: (626)
Cell: (626)