Earthquake Intensity Database, 1638–1985
National Oceanic and Atmospheric Administration
Department of Commerce
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Maintainer: PANG
Downloaded on: 2025-04-22
Notes:
The U.S. Earthquake Intensity Database (1638–1985) is a collection of damage and felt reports for more than 23,000 U.S. earthquakes. The database contains information regarding epicentral coordinates, magnitudes, focal depths, names, and coordinates of reporting cities/ localities, reported intensities, and the distances to the epicenter. Earthquakes listed in the file date from 1638 to 1985. The majority of the felt reports are in the U.S. States and Territories (155,301). Other reporting countries include Antigua and Barbuda (2), Canada (1,364), Mexico (54), Panama (285), and the Philippines (9).
Maintainer: SUL
Downloaded on: 2025-04-24
Notes:
This copy of the United States Earthquake Intensity Database 1638-1985 was made on April 24, 2025 before the original dataset landing page at https://www.ncei.noaa.gov/products/natural-hazards/tsunamis-earthquakes-volcanoes/earthquakes/intensity-database-1638-1985 was decommissioned on May 5, 2025. This deposit also includes the html of the original dataset landing page for reference. See this NOAA NCEI record for more metadata and current access options.Original dataset descriptionThe U.S. Earthquake Intensity Database (1638–1985) is a collection of damage and felt reports for more than 23,000 U.S. earthquakes. The database contains information regarding epicentral coordinates, magnitudes, focal depths, names, and coordinates of reporting cities/ localities, reported intensities, and the distances to the epicenter. Earthquakes listed in the file date from 1638 to 1985. The majority of the felt reports are in the U.S. States and Territories (155,301). Other reporting countries include Antigua and Barbuda (2), Canada (1,364), Mexico (54), Panama (285), and the Philippines (9).Database DescriptionThe Earthquake Intensity File contains more than 157,000 reports on over 20,000 earthquakes that affected the United States from 1638 through 1985. The principal data included for each earthquake are the names and geographic coordinates of the cities/localities that reported effects from earthquakes, (hereafter called "reporting cities") and the intensities assigned to those effects. Each intensity has been assigned using the Modified Mercalli Intensity Scale of 1931 (Wood and Neumann, 1931). Other information given for each earthquake includes distance of each reporting city from the epicenter of the earthquake; number of hours to subtract from Universal Time (UT) to obtain origin time in local standard time; reference (authority) codes for reporting cities and intensity values, and state codes. In addition, the date, origin time, epicenter, magnitude, and depth (where available) are given for all earthquakes.Although the Earthquake Intensity File represents an important contribution to seismology research, it has several limitations that should be mentionedAbout 25 percent of the 2,500 earthquakes reported from 1638-1928 and 10 percent of the 18,500 events from 1928-1980 do not have instrumental epicenters; this omission is mainly due to the fact that seismological instruments were not developed until the late 1800s, and further that the instruments were not widely distributed for many years later.Several of the reporting cities listed in the file have not been assigned geographic coordinates.The file contains data primarily for those earthquakes that have epicenters in the United States, nearby U.S. territories, and areas of Canada and Mexico that border the United States. Data for a few events in the Philippines (from the late 1930s through 1941) is also included.