Faults in Focus:Earthquake Science Accomplishments

Thomas H. Jordan

Director, Southern California Earthquake Center28 February 2014

Land-Use Policies& Planning

Risk = Probable Loss (lives & dollars) =

Hazard × Exposure × Fragility ÷ Resilience

Structural & nonstructural vulnerability

Extent & density of built environment

Faulting, shaking, tsunami, landsliding,

liquefaction

Disaster response,insurance, CAT bonds

Earthquake Engineering& Building Codes

Eqk Preparedness & Emergency Response

Hazard Characterization is the Key to Risk Reduction

Dire

ct E

cono

mic

Los

s ($

bill

ions

)Economic Losses in Four Recent U.S. Earthquakes

> $40 billion

17 Jan 1994 Northridge Earthquake (M6.7)occurred on an unknown blind thrust fault…

mainshock

aftershocks

N

N

Science Accomplishments• Since Northridge, earthquake science sponsored by the USGS and

NSF has

– improved our understanding of seismic hazards for land-use planning, earthquake engineering, earthquake preparedness, and emergency management

– enabled new technologies for tracking earthquake cascades, including operational earthquake forecasting (OEF) and earthquake early warning (EEW)

Earthquake origin time

Southern California Seismic Network in 2014

1. Development of the Advanced National Seismic System (ANSS)

High-performance stations

2. Improved mapping of seismic activity

Northridge fault in yellowOther blind thrust faults in red

LA center

Southern California Fault Model (2013)

3. Improved mapping of active faults

Projected losses

$82 B - $252 B3,000 - 18,000 fatalities142,000 -735,000 displaced households30,000 - 99,000 tons of debris

Puente Hills EarthquakeScenarios(Magnitude 7.1 to 7.5)

Percent Building Loss

M7.2

Field et al. (2005)

4. Better earthquake scenarios

5. Deployment of dense geodetic networks to measure deformation

Pacific-North America plate motion

50 mm/yr

North American plate

Pacific plate

San Andreas Fault

Southern California Integrated GPS Network (SCIGN)

North American plate

Pacific plate

San Andreas Fault

Southern California Integrated GPS Network (SCIGN)

5. Deployment of dense geodetic networks to measure deformation

Pacific-North America plate motion

50 mm/yr

UCERF2

Earthquakes

Active Faults

Tectonic Motions

6. Integration of seismic, geodetic, and geologic data into probabilistic earthquake rupture forecasts

Uniform California Earthquake Rupture Forecast (UCERF)

New release in 2014

National Seismic Hazard Map (2008)

7. National Seismic Hazard Mapping Project (NSHMP)

ShakingIntensity

Eqk RuptureForecast

Ground MotionModel

LA region

SFBA

8. Development of simulation-based urban seismic hazard models

CyberShake (2013) Hazard Model

CyberShake model of the Los Angeles region, comprising over

200 million synthetic seismograms

8. Development of simulation-based urban seismic hazard models

Simulation of M7.8 Earthquake on the Southern San Andreas Fault

9. Deployment of a prototype Earthquake Early Warning system

Simulation of M7.8 Earthquake on the Southern San Andreas Fault

Seismic stations

Earthquake Early Warning

Simulation of M7.8 Earthquake on the Southern San Andreas Fault

Conclusions and Recommendations

• Earthquake science sponsored by the USGS and NSF has

– improved our understanding of seismic hazards for land-use planning, earthquake engineering, earthquake preparedness, and emergency management

– enabled new technologies for tracking earthquake cascades, including operational earthquake forecasting (OEF) and earthquake early warning (EEW)

• Congress should

– reauthorize the National Earthquake Hazards Reduction Program to continue this R&D and its implementation

– fund the USGS to deploy OEF and EEW systems in California, Washington, and other at-risk states

End