thumbnail

Seismicity map of the State of Alabama

Miscellaneous Field Studies Map 1059

By:
, , and

Links

Abstract

The earthquake data shown on this map and listed in table 1 are a list of earthquakes that were originally used in preparing the Seismic Risk Studies in the United States (Algermissen, 1969) which have been recompiled and updated through 1977. The data have been reexamined and intensities assigned where none had been assigned before, on the basis of available data. Other intensity values were updated from new and additional data sources that were not available at the time of original compilation. Some epicenters were relocated on the basis of new information. The data shown in table 1 are estimates of the most accurate hypocenter, magnitude, and intensity of each earthquake, on the basis of historical and current information. Known or suspected explosions are listed in table 1 but are not plotted on the seismicity map.

The data in table 1 were used to compile the seismicity map. The latitude and longitude were rounded to the nearest tenth of a degree and sorted so that all identical locations were grouped together and counted. A triangle represents the epicenter plotted to a tenth of a degree. The number of earthquakes at each location is shown on the map by the 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 located at that geographic position. The absence of an intensity value indicates that no intensities have been assigned to earthquakes at that location. A year shown below a 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 Alabama
Series title:
Miscellaneous Field Studies Map
Series number:
1059
Year Published:
1979
Language:
English
Publisher:
U.S. Geological Survey
Description:
24.64 inches x 34.19 inches
Country:
United States
State:
Alabama
Scale:
1000000
Additional Online Files (Y/N):
N