ML20030A465
| ML20030A465 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 10/19/1959 |
| From: | Joshua Wilson CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.), MICHIGAN, UNIV. OF, ANN ARBOR, MI |
| To: | |
| References | |
| NUDOCS 8101090575 | |
| Download: ML20030A465 (4) | |
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SEISMICITY OF THE CHARLEVOIX, MICHIGAN, AREA James T. Wilson Professor of Geology University of Michigan No earthquakes.of any consequence have occurred within 100 miles of Charlevoix in historic times and only a few small shocks have occurred within about 200 miles. In assessing the seismicity of a particular area the historical record is the most usual and accepted information and, together with the geology of the area, comprises about all the data available. On this basis one would assign a very low seismicity to the Charlevoix region.
All such assignments must be qualified with a word of caution, however, as earthquakes have been known to occur in areas where there has been a long history of no shocks. However, on the basis of the historical record and the structurally uncomplicated geology, one would assign a far lower probability of damaging (or even felt) earthquakes to this area than to the St. Lawrence valley or the central Mississippi valley, to say nothing of California or western Nevada. The data may be summarized by pointin6 out that the historical record (through 1956) shows no earthquake of consequence in Wisconsin and only three small shocks in the Upper Peninsula of Michigan and four small shocks in the Lower Peninsula.
Figure 1 reproduces that part of the map from " Earthquake History of the United States, Rev (1956) Ed, U.S. Dept of Com Publ 41-1",
of interest to this discussion. The intensities given on the map legend as (MM) are in the modified Mercalli Scale of 1931. It may be summarized as follows:
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- t MM 4 - Walls creak, windows rattle.
MM 6 - Felt by'all. -Damage slight. Some fallen plaster Y
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or damaged chimneys.
MM 8 - Damage slight in specially designed structures; considerable in ordinary structures.
The intensities shown on the map are for the area close to the center of the shock.
Table 1 summarizes the historical record for the area N latitude and 500 N latitude, and between 800 W longitude
- between 420 and 900 W longitude.
TME 1 1804, August 20.
Near Chicago. Felt over an area of 30,000 square miles.
1872, February 6.
Three small shocks near Wenona, Michigan (east.of Saginav).
1877, August 17 Small shock in southea' stern Michigan.
1883, February 4.
Small shock near Kalamazoo, Michigan. Felt over T
8,000 square miles.
i 1905, March 13 MM intensity 5 at Menominee, Michigan.
1905, July 26. The Earthquake History of the U.S. reports, "An earth-quake which-was apparently associated in some way with the peculiarly unstable conditions brought about by mining operation was felt all over the Keweenaw Peninsula, Michigan. It was heaviest at Calumet.
.There was a terrific explosion, chimneys fell with a crash, and I
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plate glass windows broke. The explosion was heard far down in the mine. Felt at Marquette, Michigan."
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1906, July 26. The Earthquake History of the U.S. reports, "At the Atlantic Mine on Keweenaw Peninsula the effects were such as might be produced by a great earthquake. Rails were twisted and there was notable sinking of the earth above the workings. Such effects were noted nowhere else, though at Madison, Wisconsin, there were three distinct shocks, at Lansing furniture swayed and at Muskegon along the lake shore dishes were upset and windows shaken. The area affected was about 1,000 miles in diameter."
1909, January 22.
Small shock at Houghton, Michigan.
1909, May 26. MM intensity 7 in northern Illinois. Felt over an area 800 miles across.
1935, November 1.
Timiskaming, Ontario. This is just out of the area, but it is listed as it is probably the largest shock felt in Michigan in historic times. Some slight damage in the Detroit area.
1943, March 8.
Small shock in central Lake Erie.
1947, August 9 South-central Michigan. MM intensity 6 north of Coldwater. Felt over an area of 50,000 square miles.
The May 26, 1906 shock centering on the Keweenaw Peninsula was probably felt more strongly at Charlevoix than any other but there seems to have been no damage except in the mining area of the Keweenaw Peninsula and this seems to have been related to the mining operation.
October 19, 1959 I
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o, EARTHQUAKES OF THE UNITED STATES Through 1956 Exclusive of Cabfornis and aestern Nevada c w.e n, c se e.e a e c sw,
Esequakes of mtensdy 5-6 (MM) o Fet sera less than 50000 se a la$4usees el mtensity 7-8 (liif) g Fen area 50 000-250 000 se a Eseemehes of stensdy 9-10 (MM) g Fen ares 250E75C(D0 sq n 9 arthquakes of miensity 11-12(MM]
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P00R ORIGINAL Figure 1.
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