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

USGS Earthquake Hazards Program

Earthquakes 101

Global Distribution of Earthquakes

Lisa WaldUSGS Pasadena

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

USGS Earthquake Hazards Program

Plate Tectonics

Plate Boundaries

Three Types of Faults

Strike-SlipReverse

Normal

Strike-slip Fault Example

Normal Fault Example

Dixie Valley-Fairview Peaks, Nevada earthquakeDecember 16, 1954

Reverse Fault Example

Bigger Faults Make Bigger EarthquakesBigger Faults Make Bigger Earthquakes

1

10

100

1000

5.5 6 6.5 7 7.5Magnitude

Kilo

me

ters

8

Bigger Earthquakes Last a Longer TimeBigger Earthquakes Last a Longer Time

1

10

100

5.5 6 6.5 7 7.5 8

Magnitude

Sec

onds

What Controls the Level of Shaking?What Controls the Level of Shaking?

• Magnitude– Amount of energy released

• Distance– Shaking decreases with distance

• Local soils– Amplify or absorb the shaking

Is there such a thing as “Earthquake Weather”???

Earthquake Effects - Ground Shaking

Northridge, CA 1994

Earthquake Effects -Ground Shaking

Northridge, CA 1994

Earthquake Effects - Ground Shaking

Kobe, Japan 1995

Earthquake Effects - Ground Shaking

KGO-TV News ABC-7

Loma Prieta, CA 1989

Earthquake Effects - Ground Shaking

Japan 2011

Earthquake Effects - Surface Faulting

Landers, CA 1992

Earthquake Effects - Liquefaction

Sendai, Japan, 2011

Earthquake Effects - Landslides

Turnnagin Heights,Alaska,1964

Source: National Geophysical Data Center

Earthquake Effects - Fires

Japan 2011

Loma Prieta, CA 1989

Earthquake Effects - Tsunamis

Seismic Waves

Earthquake Magnitude

M5

M6

M7

Earthquake Location

The San Andreas Fault

Faultsof SouthernCalifornia

Source: SCEC Data Center

Shaking Hazard in Southern California

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

USGS Earthquake Hazards Program

http://earthquake.usgs.gov/

Where to go for more information: