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Why is the earthquake that was reported/recorded by network X, or that I felt, not on the Latest Earthquakes map/list?

The USGS Latest Earthquakes map and lists show events that have been located by the USGS and contributing agencies within the last 30 days. They should NOT be considered complete lists of all events in the U.S. and adjacent areas and especially should NOT be considered complete lists of all magnitude 4.5 and greater events that occur around the globe.

In most cases, we locate and report an earthquake in 30 minutes or less of its occurrence when:

  • A worldwide earthquake is of magnitude 5.0 or larger.
  • An earthquake within the contiguous U.S. and populated regions of Alaska is of magnitude 4.0 and larger.

Earthquakes of magnitude 2.0 or greater within the U.S. and populated regions of Alaska are usually reported rapidly if they occur within the region of a contributing local seismic network.

Our Latest Earthquakes map might not display earthquakes smaller than 5.0 outside the U.S. unless they have caused significant damage or are widely felt (earthquakes this small rarely cause significant damage). At times, some other agency might report an earthquake with a larger magnitude than what we compute from our data, especially for non-U.S. events near magnitude 5.0. 

Earthquakes occurring outside the U.S. that are smaller than about magnitude 4.5 can be difficult for the USGS to locate if there are not enough data. The USGS continues to receive data from observatories throughout the world for several months after the events occur. Using those data, we add new events and revise existing events in our Earthquake Catalog and in later publications.

There are many regional networks around the world that can record smaller earthquakes in their region than the National Earthquake Information Center (NEIC) global network can, and in many cases these regional networks do not share their data with the NEIC. So if you think there is a missing earthquake on our maps and lists, please see the national and regional links for the area of interest:

 

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