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SAFRR - Science Application for Risk Reduction

Tsunami Scenario


After two years of work, on September 4th, 2013, the SAFRR Tsunami Scenario, a scientific report on a hypothetical but plausible tsunami created by a magnitude 9.1 earthquake offshore of the Alaskan peninsula, was released.

The report is an analysis of the potential impacts along the California coast, intended for those who need to make mitigation, preparedness, and outreach decisions before tsunamis and those who will need to make rapid decisions during and after tsunamis. The Tsunami Scenario will help them understand the context and consequences of their decisions that can improve preparedness and response.

The State of California is convening workshops between September 4th and 10th hosted by local entities in Los Angeles, Santa Barbara, San Diego, Santa Cruz, and San Francisco to explain the scientific results of the study to stakeholders.

The Tsunami Scenario development is a collaboration among:

  • the U.S. Geological Survey (USGS)
  • the California Geological Survey (CGS)
  • the California Governor's Office of Emergency Services (Cal OES)
  • the National Oceanic and Atmospheric Administration (NOAA)
  • and other agencies, and academic and other institutions (see full report).

The Tsunami Scenario Report presents:

  • geologic evidence of historical and pre-historical tsunamis
  • modeling of tsunami generation and propagation
  • likely inundation areas
  • current velocities in key ports and harbors
  • physical damage and repair costs
  • economic consequences
  • environmental impacts
  • ecosystem impacts
  • social vulnerability
  • emergency management and evacuation challenges
  • policy implications for California
  • communication products
  • assistance to on-going work by the California tsunami program.

Highlighted Results:

  • Distant tsunamis, although not as life-threatening as a large local event, can still lead to billions of dollars in losses in California.

  • The largest economic impacts to the state pertain to damage and incapacitation of our ports and harbors, and damages to coastal properties.

  • In California marinas, one third of the boats could be damaged or sunk and two thirds of the docks damaged or destroyed, resulting in at least $700 million of loss.

  • One quarter of a million people live in the maximum inundation zones mapped by the State of California and would likely be evacuated. An additional quarter of a million tourists and visitors may be on the coast if the scenario were to occur in March (tourist numbers could increase into the millions during the summer months).

  • 8,500 residents in the SAFRR Tsunami Scenario inundation zone would likely need shelter because of damage to their homes. Evacuations will also be a challenge for certain areas with limited access and dependent-care populations.

  • Visitors, in particular, are not typically well-educated about tsunamis, and often only those living in areas having recently experienced a tsunami have been educated. Everyone visiting and living near the beach should know their vulnerability and what to do (e.g., know where the closest high ground is and how to reach it).

The Good News:

  • Three-quarters of California's coastline is cliffs and thus protected from many of the impacts of tsunamis.
  • Neither of California's nuclear power plants are damaged in this scenario.
  • Ports and other sectors have the capacity to reduce the economic impacts in California, and this report outlines the potential effectiveness of resilience strategies in place that can be implemented to do so.

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Page Last Modified: Friday, April 25, 2014