Probabilities, Seismic Hazard & Earthquake Engineering Q: Are earthquake probabilities or forecasts the same as prediction? A: No. Probabilities are estimated from the rate of aftershocks and these are sometimes confused with the prediction of a particular event. Q: What is the probability that an earthquake will occur in the Bay Area? A: Within the next 30 years the probability is 67% that an EQ measuring >6.7 will occur in the Bay Area. Q: What is the probability that an earthquake will occur in the LA Area? A: Within the next 30 years the probability is 60% that an EQ measuring >6.7 will occur in Southern California. Q: What is seismic hazard and how is it determined? A: Seismic hazard is the hazard associated with potential earthquakes in a particular area. Q: How will my house hold up in an earthquake? Can the USGS send someone out to evaluate my property? A: Published maps will only provide generalized, uninterpreted information about specific areas. Every property consists of a unique combination of geologic and structural factors that must be considered to determine what might happen to a house during an earthquake. Therefore, an individual site study is necessary. Geologic factors include: type of underlying material, depth to bedrock, depth of groundwater, and slope of land. Structural factors include: materials used (wood or masonry) in construction, number of floors, design, and retrofitting present. As a publicly-funded organization, the U.S. Geological Survey conducts regional hazard assessments in conjunction with State and local agencies. We provide information that is used by planning officials to mitigate hazards. The USGS does not undertake assessments of individual private property. Site studies must be arranged by the owner of the property with geologists or engineers in private practice. To locate a qualified professional, contact your State government to determine its certification or licensing requirements for professional geologists and engineers in private practice. State boards of registration maintain lists of individuals who meet requirements established in their State. A local real estate company may also be able to recommend a qualified professional. Q: How are engineers working to make roads and buildings safer? A: Earthquake engineers are working to make roads and buildings safer in the event of a major earthquakes. This includes both improving the design of new buildings and bridges as well as strengthening older units to incorporate the latest advances in seismic and structural engineering. The Federal Emergency Management Agency plays a central role in funding research and development for the purpose of mitigating the effects of earthquakes Q: What is the USGS doing to mitigate and respond to earthquake hazards? A: The U.S. Geological Survey performs the following functions related to earthquake hazard mitigation: Receives, analyzes, maintains, and distributes data on earthquake activity worldwide. Satellites link our National Earthquake Information Center in Golden, Colorado to a network of seismograph stations. These stations, located throughout the world, are maintained by the U.S. Geological Survey, State geological surveys, universities, research institutions, and foreign governments. Provides rapid notification of earthquake events to civil defense and government officials in the affected area, and to the public through the news media. Produces regional assessments of earthquake hazards in conjunction with State and local governments. This information is used by: local planners and building officials in setting appropriate building and retrofitting standards in an area government and civil defense officials in planning for disaster recovery professionals conducting detailed site assessments researchers engaged in basic and applied research. Engages in basic research to learn more about the nature of earthquake activity. Provides education on earthquake hazards and safety to the public by publishing and distributing literature, and through a variety of other outreach efforts. Q: How do I decide whether or not to get earthquake insurance? A: You should consider the following factors when deciding whether or not to get earthquake insurance: proximity to active earthquake faults seismic history of the region (frequency of earthquake time since last earthquake building construction (type of building. and foundation architectural layout materials used quality of workmanship extent to which earthquake resistance was considered by the designer local site conditions (type and condition of soil slope of the land fill material geologic structure of the earth beneath annual rainfall value of the building and its contents cost of the insurance and restrictions on coverage (i.e. the deductible).