Seismological Research Letters; November/December 2006; v. 77; no. 6;
p. 672-676; DOI: 10.1785/gssrl.77.6.672
© 2006 Seismological Society of America
Ranking States by Seismic Activity
John G. Anderson
Nevada Seismological Laboratory and Department of
Earth and Engineering Sciences, University of Nevada,
Reno
Yuichiro Miyata
Nevada Seismological Laboratory,
University of Nevada, Reno
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Frequently, one sees comparisons and rankings of the various states.
Perhaps it is interesting to compare the states by numbers of earthquakes. The
main value of such a ranking is to provide an additional means to convey the
importance of earthquake hazard awareness to the general population and to
motivate earthquake preparedness and mitigation in the more active states.
We consulted the catalog of earthquakes compiled by the Advanced National
Seismic System (ANSS) and made available through the Northern California
Earthquake Data Center
(http://www.ncedc.org/anss/catalog-search.html).
The catalog contains data from 1898 to 2005. Earthquakes in the catalog with
magnitude 5.0 or greater are shown in
figure 1. The ANSS catalog has
varying levels of completeness, and most regions do not have earthquake
entries going back to 1898. To compensate for incompleteness at the larger
magnitudes, we supplemented the ANSS catalog with the catalog of significant
U.S. earthquakes (1568–1989) available from the U.S. Geological Survey
on the World Wide Web at
http://neic.usgs.gov/neis/epic/epic.html.
This extends the seismic history at the larger magnitudes. It is beyond the
scope of this paper to seek out and incorporate regional studies that might
provide a higher level of completeness, so the ranking in
table 1 and the curves in
figure 2 are limited to what
can be inferred from the ANSS and USGS catalogs. We will address the issue of
catalog completeness later.
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Figure 1. Epicenters of earthquakes with magnitude 5.0 or greater, 1755–2005,
based on the ANSS seismicity catalog
(http://www.ncedc.org/anss/catalog-search.html)
and the USGS Catalog of Significant Earthquakes after 1769
(http://neic.usgs.gov/neis/epic).
We also have edited in the 1755 Cape Ann earthquake.
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View this table:
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TABLE 1 Numbers of earthquakes, by magnitude, in the 10 most active states based
on the ANSS catalog (1898–2005) and Significant U.S. Earthquakes
(1568–1989).*
For those states that have coastlines, this . . . [Full Text of this Article] |
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Nevada Seismological Laboratory and
Department of Earth and
Engineering Sciences
University of Nevada
Reno, Nevada
89557
jga@seismo.unr.edu
(J.G.A.)
Nevada Seismological Laboratory
University of Nevada
Reno,
Nevada
89557
yui@seismo.unr.edu
(Y.M.)
Copyright © 2009 by Seismological Society of America