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Most earthquakes are caused by the sudden release of built-up stress along faults, fractures in the Earth’s crust where large blocks of crustal rock move against one another. An earthquake’s size can be measured by the amount of energy released by that movement. While scientists can't predict earthquakes, they are developing earthquake early warning systems that can provide seconds to minutes of warning when an earthquake occurs. Scientists can also estimate the likelihood of future quakes and use that information to design safer buildings and roads.

Why do earthquakes matter?

Large earthquakes pose a substantial threat along the West Coast and portions of the central and eastern United States. A single event can be devastating: for example, the 1994 Northridge, CA, magnitude 6.7 earthquake caused at least $40 billion in direct damage and killed around sixty people.[1][2] While the West Coast has the most active faults, earthquakes can also affect the Central and Eastern United States, as they did during the 1811 and 1812 New Madrid earthquakes and 1886 Charleston, SC earthquake. Earthquakes not only affect the United States; they are a global hazard, taking millions of lives since 1900.[3]

How does geoscience help inform decisions about earthquake hazards?

Geoscientists measure earthquakes to pinpoint where they are occurring and determine the long-term earthquake hazard an area may face. This understanding of potential earthquake hazard is crucial for urban planning and earthquake-resistant design of buildings and infrastructure. Geoscientists are also developing earthquake early warning systems to give a few seconds of early warning once an earthquake has been detected.

Introductory resources

A basic definition of earthquakes, what causes them, why they cause shaking, how they are recorded, how scientists can tell where an earthquake happened, and how scientists measure their size.

Frequent questions


  1. Historic Earthquakes, USGS Earthquake Hazards Program,
  2. The Significant Earthquake Database, NOAA National Geophysical Data Center,
  3. Earthquakes with 1,000 or More Deaths since 1900, USGS Earthquake Hazards Program,

See also

External links

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