Estimating locations and magnitudes of earthquakes in eastern North America from Modified Mercalli intensities

Bulletin of the Seismological Society of America
By: , and 

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Abstract

We use 28 calibration events (3.7 < or = M < or = 7.3) from Texas to the Grand Banks, Newfoundland, to develop a Modified Mercalli intensity (MMI) model and associated site corrections for estimating source parameters of historical earthquakes in eastern North America. The model, MMI = 1.41 + 1.68 XM - 0.00345X Delta - 2.08log (Delta), where Delta is the distance in kilometers from the epicenter and M is moment magnitude, provides unbiased estimates of M and its uncertainty, and, if site corrections are used, of source location. The model can be used for the analysis of historical earthquakes with only a few MMI assignments. We use this model, MMI site corrections, and Bakun and Wentworth's (1997 technique to estimate M and the epicenter for three important historical earthquakes. The intensity magnitude M1 is 6.1 for the 18 November 1755 earthquake near Cape Ann, Massachusetts; 6.0 for the 5 January 1843 earthquake near Marked Tree, Arkansas; and 6.0 for the 31 October 1895 earthquake. The 1895 event probably occurred in southern Illinois, about 100 km north of the site of significant ground failure effects near Charleston, Missouri.

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Publication type Article
Publication Subtype Journal Article
Title Estimating locations and magnitudes of earthquakes in eastern North America from Modified Mercalli intensities
Series title Bulletin of the Seismological Society of America
DOI 10.1785/0120020087
Volume 93
Issue 1
Year Published 2003
Language English
Publisher Seismological Society of America
Description 13 p.
First page 190
Last page 202
Country United States
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