Frequently Asked Questions
Natural Hazards
The USGS monitors and conducts research on a wide range of natural hazards to help decision-makers prepare for and respond to hazard events that threaten life and property.
Los Angeles area:
Within the next 30 years the probability is:
60% that an earthquake measuring magnitude 6.7
46% that an earthquake measuring magnitude 7
31% that an earthquake measuring magnitude 7.5
will occur in the Los Angeles region.
San Francisco Bay area:
Within the next 30 years the probability is:
72% that an earthquake measuring...
The National Seismic Hazards Mapping project provides an online web tool for determining the probability of a large earthquake within 50 kilometers (~31 miles) of a specific location over a certain time period. The calculation is based on the latest available information from seismic hazard data.
Unified Hazard Tool - Earthquake Hazard and...
Ground shaking is the primary cause of earthquake damage to man-made structures. Many factors influence the strength of earthquake shaking at a site including the earthquake's magnitude, the site's proximity to the fault, the local geology, and the soil type.
More than 250 structures throughout the United States have been outfitted with seismic...
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 earthquakes)
time since last earthquake
building construction (type of building and foundation)
architectural layout
materials used
quality of workmanship
extent to...
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...
Determining your risk with regard to earthquakes, or more precisely shaking from earthquakes, isn't as simple as finding the nearest fault. The chances of experiencing shaking from an earthquake and/or having property damage is dependent on many different factors. The National Hazard Maps use all available data to estimate the chances of shaking (...
Seismic hazard is the hazard associated with potential earthquakes in a particular area, and a seismic hazard map shows the relative hazards in different areas. The maps are made by considering what we currently know about:
Past faults and earthquakes
The behavior of seismic waves as they travel through different parts of the U.S. crust
The near-...
Although you may hear the terms “seismic zone” and “seismic hazard zone” used interchangeably, they really describe two slightly different things. A seismic zone is used to describe an area where earthquakes tend to focus; for example, the New Madrid Seismic Zone in the Central United States. A seismic hazard zone describes an area with a...
In a few cases, yes, but in most cases no. Only a few of the over 2000 magnitude 3 and larger earthquakes since 2009 that have occurred in Oklahoma have been connected to hydraulic fracturing. The majority of earthquakes in Oklahoma are caused by the industrial practice known as "wastewater disposal". Wastewater disposal is a separate process...
USGS supports both internal and external (university-based) research on the causes of induced earthquakes. This research focuses on injection-induced earthquakes, including from wastewater disposal, enhanced geothermal technologies, and at carbon dioxide sequestration sites. USGS and its university partners have also deployed seismometers at sites...
To produce natural gas from shale formations, it is necessary to increase the interconnectedness of the pore space (permeability) of the shale so that the gas can flow through the rock mass and be extracted through production wells. This is usually done by hydraulic fracturing ("fracking"). Fracking causes extremely small earthquakes, but they are...
So far, there is no conclusive example linking injection operations to triggering of major earthquakes. However, we cannot eliminate this possibility.
Learn more: USGS Induced Earthquakes