Working Potter on tue 23 apr 02
1886
We are overdue here they are telling us and they are in the process of
reinforcing a huge earthen dam here that did not pass muster.
''Misty"
Charleston, South Carolina 1886 September 01 02:51 UTC (local August 31),
7.3, MM X
HREF="http://neic.usgs.gov/neis/eqlists/USA/1886_09_01_iso.html">Isoseismal
Map HREF="http://neic.usgs.gov/neis/eqlists/USA/1886_09_01_pics.html">Damage
photos This is the most damaging earthquake to occur in
the Southeast United States and one of the largest historic shocks in
Eastern
North America. It damaged or destroyed many buildings in the old city of
Charleston and killed 60 people. Hardly a structure there was undamaged, and
only a few escaped serious damage. Property damage was estimated at $5-$6
million. Structural damage was reported several hundred kilometers from
Charleston (including central Alabama, central Ohio, eastern Kentucky,
southern Virginia, and western West Virginia), and long-period effects were
observed at distances exceeding 1,000 kilometers. Effects in the epicentral
region included about 80 kilometers of severely damaged railroad track and
more than 1,300 square kilometers of extensive cratering and fissuring.
Damage to railroad tracks, about 6 kilometers northwest of Charleston,
included lateral and vertical displacement of tracks, formation of S-shaped
curves and longitudinal movement. The formation of sand craterlets and the
ejection of sand were widespread in the epicentral area, but surface
faulting
was not observed. Many acres of ground were overflowed with sand, and
craterlets as much as 6.4 meters across were formed. In a few locations,
water from the craterlets spouted to heights of about 4.5 to 6 meters.
Fissures 1 meter wide extended parallel to canal and stream banks. A series
of wide cracks opened parallel to the Ashley River, and several large trees
were uprooted when the bank slid into the river. At Summerville, a small
town
of 2,000 population, 25 kilometers northwest of Charleston, many houses
settled in an inclined position or were displaced as much as 5 centimeters.
Chimneys constructed independently of the houses commonly had the part above
the roofline thrown to the ground. Many chimneys were crushed at their
bases,
allowing the whole chimney to sink down through the floors. The absence of
overturning in piered structures and the nature of the damage to chimneys
have been interpreted as evidence that the predominant motion was vertical.
The meizoseismal area of MM intensity X effects is an elliptical area,
roughly 35 by 50 kilometers, trending northeast between Charleston and
Jedburg and including Summerville. Middleton Place, about in the center of
this ellipse, is at the southeast end of a zone (perhaps 15 kilometers long)
of microearthquake activity that still continues today. This seismic
activity
may be a continuation of the 1886 aftershock series. The intraplate
epicenter
of this major shock is not unique for large earthquakes in the Eastern and
Central United States. Other intraplate earthquakes include those at Cape
Ann, Massachusetts (1755), and New Madrid, Missouri (1811-1812). Earthquakes
occurring along boundaries of plates (e.g., San Francisco, 1906) are well
understood in terms of plate tectonics, but those occurring within plates
are
not similarly understood. This problem still is being studied more than 100
years after the earthquake. This earthquake was reported from distant places
such as Boston, Massachusetts; Milwaukee, Wisconsin, Chicago, Illinois; Cuba
and Bermuda. Abridged from Seismicity of the United States, 1568-1989
(Revised), by Carl W. Stover and Jerry L. Coffman, U.S. Geological Survey
Professional Paper 1527, United States Government Printing Office,
Washington: 1993. See also HREF="http://neic.usgs.gov/neis/eqlists/10maps_usa.html">Largest Earthquakes
in the United States.
USGS National Earthquake Information Center
USGS Privacy Statement | HREF="http://www.usgs.gov/disclaimer.html">Disclaimer
Maintained by: M. Zirbes HREF="http://eqint.cr.usgs.gov/neic/cgi-bin/sitemail1.cgi?docname=WEB_Team`/
neis/eqlists/USA/1886_09_01.html`">Feedback
Updated: Thursday, 2001 April 05 12:38:27 MDT URL:
http://neic.usgs.gov/neis/eqlists/USA/1886_09_01.html
| |
|
