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USGS1982

Distribution of intensity for the Westmorland, California, earthquake of April 26, 1981

The maximum Modified Mercalli intensity of the April 26, 1981 earthquake located 5 km northwest of Westmorland, California is VII. Twelve buildings in Westmorland were severely damaged with an additional 30 sustaining minor damage. Two brick parapets fell in Calipatria, 14 km northeast of Westmorland and 10 km from the earthquake epicenter. Significant damage in rural areas was restricted to unreinforced, concrete-lined irrigation canals. Liquefaction effects and ground slumping were widespread in rural areas and were the primary causes of road cracking. Preliminary local government estimates of property loss range from one to three million dollars (Imperial Valley Press, 1981). The earthquake was felt over an area of approximately 160,000 km2; about the same felt area of the October 15, 1979 (Reagor and others, 1980), and May 18, 1940 (Ulrich, 1941) Imperial Valley earthquakes.

Open-File Report↗

USGS1981

Seismicity map of the State of Maine

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. These data have been reexamined which resulted in some revisions of epicenters and intensities as well as assignment of intensities to earthquakes that previously had none assigened. Intensity values were updated from new and additional data soureces that were not available at the time of original compilation. Some epicenters were relocated on the basis of new informaition. The data shown in table 1 are estimates of the most accurate epicenter, magnitude, and intensity of each earthquake, on the basis of historical and current information. Some of the aftershocks from large earthquakes are listed but are incomplete in many instances, especialy for ones that occurred before seismic instruments were in universal usage. Only earthquakes located within the borders of the states of Maine are listed. This map superceeds Miscellaneous Field Sudies Map MF-845.

Maine↗

USGS1980

Seismicity map of the State of New Jersey

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 New Jersey, even though earthquakes in nearby states may have been felt or may have caused damage in New Jersey.

New Jersey↗

USGS1980

Seismicity map of the State of New Hampshire

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 New Hampshire, even though earthquakes in nearby states or countries may have been felt or may have caused damage in New Hampshire.

New Hampshire↗

USGS1980

Seismicity map of the State of Vermont

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 in the United States (Algermissen, 1969) which have been recompiled and updated through 1977. These data have been reexamined which resulted in some revisions of epicenters and intensities as well as assignment of intensities to earthquakes that previously had none assigned. 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 epicenter, magnitude, and intensity of each earthquake, on the basis of historical and current information. Some of the aftershocks from large earthquakes are listed but are incomplete in many instances, especially for ones that occurred before seismic instruments were in universal usage.

Vermont↗

USGS1980

Seismicity map of the state of Massachusetts

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 in the United States (Algermissen, 1969) which have been recompiled and updated through 1977. These data have been reexamined which resulted in some revisions of epicenters and intensities as well as assignment of intensities to earthquakes that previously had none assigned. 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 epicenter, magnitude, and intensity of each earthquake, on the basis of historical and current information. Some of the aftershocks from large earthquakes are listed but are incomplete in many instances, especially for ones that occurred before seismic instruments were in universal usage.

Massachusetts↗