Anvil Rock EarthCache
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The above coordinates should bring you into view of a (large) piece
of geological/historical evidence. Anvil Rock.
This large boulder has been resting in its current location since
December 16, 1811.
Kentucky is affected by earthquakes from several seismic zones in
and around the state. The most important one is the New Madrid
Seismic Zone, in which at least three great earthquakes, each
estimated to have been greater than magnitude 8 on the Richter
scale, occurred from December 1811 to February 1812. Though the
state was sparsely settled, these great earthquakes affected the
whole Commonwealth of Kentucky . The following quotes are taken
from newspaper articles published after the December 16, 1811,
quake.
Frankfort . "About two o'clock on Sunday night was felt in this
place a violent shock of an earthquake. It continued for several
minutes and produced a considerable vibration of houses. Some
bricks are said to have fell from the top of the court house
chimney" (The American Republic, Frankfort , Ky. ).
Henderson . "A severe shock of an earthquake was felt at this place
on the 16th inst. At half past 2 o'clock, A.M. -- many chimneys
were cracked by the motion; -- and at sun-rise another shock threw
down most of the chimneys so injured" (The Weekly
Register-Chronicle, Washington , D.C. ).
Lexington . "About half after two o'clock, yesterday morning, a
severe shock of an earthquake was felt at this place: the earth
vibrated two or three times in a second, which continued for
several minutes, and so great was the shaking that the windows were
agitated equal to what they would have been in a hard gust of wind"
(Kentucky Gazette, Lexington, Ky.).
Louisville . "On Monday morning the 16th instant, this place was
visited by a most alarming Earthquake. . . . We are induced to
believe, the continuation was from 4 to 6 minutes, though some say
it was not so long; -- about an hour afterwards, another shock was
felt; and a little after sunrise, a third, which broke off several
chimneys, and injured some houses otherwise" (Poulson's American
Daily Advertiser, Philadelphia, Pa.).
Any effects an earthquake has on the earth’s surface or surface
structures are considered intensity. Earthquake intensity is often
measured by the Modified Mercalli intensity scale. This scale,
composed of 12 increasing levels of intensity that range from
imperceptible shaking to catastrophic destruction, is designated by
Roman numerals. It does not have a mathematical basis; instead it
is an arbitrary ranking based on observed effects. The following is
an abbreviated description of the 12 levels of Modified Mercalli
intensity.
I. Not felt except by a very few under especially favorable
conditions.
II. Felt only by a few persons at rest, especially on upper floors
of buildings.
III. Felt quite noticeably by persons indoors, especially on upper
floors of buildings. Many people do not recognize it as an
earthquake. Standing motor cars may rock slightly. Vibrations
similar to the passing of a truck. Duration estimated.
IV. Felt indoors by many, outdoors by few during the day. At night,
some awakened. Dishes, windows, doors disturbed; walls make
cracking sound. Sensation like heavy truck striking building.
Standing motor cars rocked noticeably.
V. Felt by nearly everyone; many awakened. Some dishes, windows
broken. Unstable objects overturned. Pendulum clocks may stop.
VI. Felt by all, many frightened. Some heavy furniture moved; a few
instances of fallen plaster. Damage slight.
VII. Damage negligible in buildings of good design and
construction; slight to moderate in well-built ordinary structures;
considerable damage in poorly built or badly designed structures;
some chimneys broken.
VIII. Damage slight in specially designed structures; considerable
damage in ordinary substantial buildings with partial collapse.
Damage great in poorly built structures. Fall of chimneys, factory
stacks, columns, monuments, walls. Heavy furniture overturned.
IX. Damage considerable in specially designed structures;
well-designed frame structures thrown out of plumb. Damage great in
substantial buildings, with partial collapse. Buildings shifted off
foundations.
X. Some well-built wooden structures destroyed; most masonry and
frame structures destroyed with foundations. Rails bent.
XI. Few, if any (masonry) structures remain standing. Bridges
destroyed. Rails bent greatly.
XII. Damage total. Lines of sight and level are distorted. Objects
thrown into the air
******Property owner has requested that you do not enter the
property (cross the fence) on which the rock is resting. Please
take photos from the road.
Source - Kentucky Geological Survey, United States Geological
Survey
In order to successfully log this earthcache, you will need to
complete all of the following steps;
1) Post a photo of yourself and your gps with Anvil Rock in the
background.
2) Email me the answer to the following. Assuming Anvil Rock was
originally located at the nearby ridgetop, estimate the distance
traveled by this boulder to its resting place.
3) Email me the answer to the following. Based upon your
observations at the posted coordinates as well as information
contained in this earthcache, estimate the Modified Mercalli value
for this area for the 1811 earthquake.
Developed by a Platinum Earthcache Master
Additional Hints
(No hints available.)