Earthquake Hazards

Earthquakes produce effects which can cause damage and loss of life. These effects, called hazards, include ground shaking, landslides and rockfall, and ground rupture (surface faulting). In general, the hazard that produces the most widespread damage and loss of life is ground shaking, because it can cause building failures and collapses at distances tens to hundreds of kilometers from the earthquake fault rupture. Recent research has focused on producing national and regional maps of probabilistic earthquake ground shaking. These maps integrate the results of research in historical seismicity, paleoseismology, strong motion seismology, and site response. The maps take into account all the possible locations and magnitudes that can happen in alternative future hypothetical earthquake histories.The maps have been produced by the USGS staff since the early 1970's, in close cooperation with engineers and building officials involved in producing building codes for earthquake-resistant building construction. As of the year 2000, all US model building codes will incorporate ground motion hazard maps derived from the USGS studies.

National & Global

• Global Seismic Hazard Assessment Program
  GSHAP was launched in 1992 by the International Lithosphere Program (ILP) with the support of the International Council of Scientific Unions (ICSU), and endorsed as a demonstration program in the framework of the United Nations International Decade for Natural Disaster Reduction (UN/IDNDR). The GSHAP project ended in 1999.
  
• National Seismic Hazard Mapping
  The USGS provides seismic hazard assessments for the U.S. and areas around the world. These hazard maps serve as the basis for seismic provisions used in building codes and influence billions of dollars of new construction every year.
  

Regional

California

• 24-Hour Forecast of Aftershock Hazard in California
  Real-time map of the chance of aftershocks following a mainshock.
  
• California Seismic Hazards Maps - California Geological Survey
  
  
• Effect of Soil Type on Shaking Hazard in the San Francisco Bay Area
  The type of soil at a site affects the intensity of shaking there. Learn about this effect and use interactive maps to look up the soil type at any site in the San Francisco Bay Area.
  
• Liquefaction Hazard and Shaking Amplification Maps of Alameda County
  Digital database identifying areas in the Oakland, California region that could produce surface liquefaction and amplify ground shaking from earthquakes.
  
• Liquefaction Susceptibility Map for San Francisco Bay Region
  Shows the distribution of rock and sediment having different vulnerabilities to liquefaction when shaken by earthquakes, together with explanation of the process and examples of its effects.
  
• Regional Earthquake Likelihood Model
  A Southern California Earthquake Center (SCEC) collaborative study to test and analyze different types of earthquake-rupture forecasts.
  
• San Francisco Bay Area Hazard Maps
  Association of Bay Area Governments offers shaking maps, liquefaction maps, predictive transportation disruption maps, and more.
  

Central and Eastern U.S.

• Reducing Hazards in the Central and Eastern U.S.
  These webpages are focused on earthquake risk and hazards in this area of the country.
  

Outside the US

• Assessing the Seismic Hazards of Afghanistan
  
  

Pacific Northwest

• Executive Summary of Pacific Northwest Earthquake Risk (PDF)
  
  
• Lifelines and Earthquake Hazards in the Greater Seattle Area
  A Pacific Northwest Urban Corridor Geologic Mapping Project of the Western Earth Surface Processes Team
  
• Pacific Northwest Urban Mapping & Geologic Hazards
  The urban corridor lies within the Puget-Willamette lowland, a seismically active forearc basin overlying the Cascadia subduction zone - Pacific Northwest Urban Corridor Geologic Mapping Project of the Western Earth Surface Processes Team