Talk:New Madrid earthquake

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[edit] Magnitude of the earthquake

There were no existing facilities in 1811 to accurately measure the magnitude of the New Madrid quake. The first seismic intensity ranking scales were not devised until after 1874, and the currently used Ricther scale was only adopted in 1935, I believe. The estimates of the New Madrid quake intensity are inferred from physical damage and from numerous witness accounts. I recall hearing anecdotes that this quake even rocked church bells in either Boston or New York (I forget which). Any quake that has affects life over 1000 miles away is very large. As an earthquake, it certainly affected the widest populated area of any in the U.S., even if it was only sparsely populated. When people say it is the largest "recorded" earthquake, they really mean the largest "witnessed" earthquake, -- however, the documentation is not the same sort of scientific record that we think of today. Based on its range of effect, if the stories from Boston and New York are to be believed, it certainly would seem to be the largest quake.


"largest earthquake ever recorded in the United States of America" while Good Friday Earthquake is "single most powerful earthquake in United States history"...?


I also don't understand this. The New Madrid earthquakes are estimated at 8, but the Good Friday Earthquake, and another on March 9, 1957 on the List of earthquakes, are both listed as being in Alaska and estimated at over 9. Could the "largest earthquake ever recorded..." have been a typo for "largest earthquake ever reported in the continental US" ?

It could be that "largest" is meant in the sense of "largest area affected", which seems rather difficult to quantify, but the article implies that this earthquake was felt over a huge area, while being at a lower intensity than some. --timc | Talk 20:59, 6 September 2005 (UTC)
Largest in the contiguous United States is what is meant by scientists.

[edit] Date of the quake

The date on the list of earthquakes in the United States puts this earthquake on Dec 16, 1811 -- which is it?

Most sources seem to call all of the events, from December 16, 1811 (first major shock) to February 7, 1812 (last major shock), and including January 23 (another major shock), the New Madrid Earthquake. This article only calls the February 7th event the New Madrid Earthquake, which does not seem consistent with other sources. --Kevin Myers 14:27, July 17, 2005 (UTC)

Is there any uncertainty about the January 23 date? I'm just now examing a letter written by Jared Mansfield, Surveyor General of the U.S., from Cincinnati on January 24, in which he says there was a large shock that very morning (the 24th) after 8 a.m. Ishboyfay (talk) 22:40, 13 December 2007 (UTC)

[edit] Bad link

The link to http://earthquake.usgs.gov/bytopic/new_madrid.html is dead and I could not readily identify an exact replacement. Perhaps http://earthquake.usgs.gov/learning/topics.php?topicID=71&topic=New%20Madrid%20Seismic%20Zone could be used. Jim 22:49, 12 June 2006 (UTC)

[edit] Largest Quake?

The first argument ended with the statement that the New Madrid was the largest to hit the contigious United States. Wasn't the Cascadia Earthquake the largest to hit contigious U.S. ? --AirLiner 15:35, 21 June 2006 (UTC)

Looks like that one was off the coast. At least it looks that way form the picture in the article. Dalf | Talk 21:42, 26 September 2006 (UTC)
The Cascadia quake probably had an epicenter that was very close to the coast; by any reasonable definition of 'hit' it would have hit the USA (earthquake shaking, not just tsunami), and it was definitely of greater magnitude - what would usually be taken to mean 'larger' with respect to an earthquake. M0ffx (talk) 22:31, 29 November 2007 (UTC)
I think it's meant that it's the largest recorded in the contiguous US. Since no one was in the area to verify the Cascadia Earthquake (or at least no one who left a record), it doesn't really count. I'm certain there were even larger quakes to hit the US than the Cascadia at some point in the history of the continent, but they weren't recorded by anyone. -GamblinMonkey (talk) 17:05, 27 March 2008 (UTC)

[edit] Adding material from German article

The German Wikipedia article is more extensive than this one, so I've translated material from it for this article. Here's the original translation request from Wikipedia:German-English_translation_requests:

de:New Madrid Earthquake
  • Corresponding English-language article: New Madrid Earthquake
  • Status: Completed. Chonak 06:22, 24 August 2006 (UTC)
  • Originally Requested by: --RobbyPrather 05:03, 12 November 2005 (UTC)
  • Other notes:

Chonak 06:22, 24 August 2006 (UTC)

[edit] April 2008 quake

Why is this mentioned in this article? It has, at the most, very little to do with the 1811-1812 event. I'm removing that in a couple of days unless there's a compelling reason why it should stay. Orpheus42 (talk) 21:18, 21 April 2008 (UTC)

Support. Please do. Cheers Geologyguy (talk) 23:30, 21 April 2008 (UTC)

[edit] What is the length of the madrid fault in miles?

What is the length of the madrid fault in miles? What is the largest fault line in North America in miles? —Preceding unsigned comment added by 171.159.64.10 (talk) 17:01, 22 April 2008 (UTC)

The New Madrid is not a single fault, but a zone. The area with the greatest seismicity, as shown here], is about 100 miles long. The San Andreas Fault is more or less a single fault with associated faults, and is something like 750 miles long. The Denali Fault in Alaska is about the same length. Hope this helps. Cheers Geologyguy (talk) 17:13, 22 April 2008 (UTC)