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: