Seismicity map of the state of Idaho

Miscellaneous Field Studies Map 1857
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This map is one of a series of seismicity maps produced by the U.S. Geological Survey that show earthquake data of individual states or groups of states at the scale of 1:1,000,000. This map shows only those earthquakes with epicenters located within the boundaries of Idaho, even though earthquakes in nearby states or countries may have been felt or may have caused damage in Idaho.

The data in table 1 were used to compile the seismicity map; these data are a corrected, expanded, and updated (through 1987) version of the data used by Algermissen (1969) for a study of seismic risk in the United States. The locations and intensities of some earthquakes were revised and intensities were assigned where none had been before. Many earthquakes were added to the original list from new data sources as well as from some old data sources that had not been previously used. The data in table 1 represent earthquake on the basis of historical and current information. Some of the aftershocks from large earthquake are listed, but not all, especially for earthquakes that occurred before seismic instruments were universally used.

The latitude and longitude coordinates of each epicenter were rounded to the nearest tenth of a degree and sorted so that all identical locations were grouped and counted. These locations are represented on the map by a triangle. The number of earthquakes at each location is shown on the map by the Arabic number to the right of the triangle. A Roman numeral to the left of a triangle is the maximum Modified Mercalli intensity (Wood and Neumann, 1931) of all earthquakes at that geographic location. The absence of an intensity value indicates that no intensities have been assigned to earthquakes at that location. The year shown below each triangle is the latest year for which the maximum intensity was recorded.

Study Area

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Seismicity map of the state of Idaho
Series title Miscellaneous Field Studies Map
Series number 1857
DOI 10.3133/mf1857
Edition Revision - 1991
Year Published 1991
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Description Report: 25 p.; Plate: 30.29 x 39.23 inches
Country United States
State Idaho
Scale 1000000
Online Only (Y/N) N
Additional Online Files (Y/N) N
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