Featured Research

from universities, journals, and other organizations

Earthquakes Would Rattle Central United States

Date:
May 29, 1998
Source:
United States Geological Survey
Summary:
The bluffs of the Mississippi River -- though they shielded Confederate inhabitants from the bombardments of Yankee gunboats during the Civil War-- will not protect the current residents from the strong ground shaking produced by potential large earthquakes.

BOSTON--The bluffs of the Mississippi River -- though they shielded Confederate inhabitants from the bombardments of Yankee gunboats during the Civil War-- will not protect the current residents from the strong ground shaking produced by potential large earthquakes.

Recent U.S. Geological Survey research reveals that there is little difference between the ground motions recorded on the Mississippi River bluffs relative to the ground motions recorded on the nearby floodplain. This evidence will be presented in the poster, Earthquake Ground Motions in the Central U.S., by Mark Meremonte and other USGS scientists from Golden, Colo., as part of the session, USGS Earthquake Hazards Program, Central and Eastern USA, on Thursday, May 28 from 8:30 a.m. to 12 p.m. in Hall C of the Hynes Veteran's Memorial Convention Center.

Most topographic highs on Earth, such as bluffs, are underlain by rock that is more resistant to erosion than the alluvium -- clay, silt, sand, gravel or similar material deposited by running water -- that generally underlies the adjacent valleys or floodplains. As a rule, seismic waves travel faster through rock than through alluvium. As they travel from high-velocity rock to low-velocity alluvium, seismic waves "pile up" -- like slow-moving traffic on a freeway -- and their amplitudes increase.

The topographic relief of the bluffs along the Mississippi River suggest that the area is also underlain by rock with a high seismic velocity and a corresponding tendency to de-amplify the ground motions of the floodplain.

"Alluvium tends to amplify ground motions relative to those of nearby rock," said Edward Cranswick, geophysicist. "On the other hand, sites underlain by rock experience less shaking than sites underlain by alluvium. Ridges are usually underlain by resistant rock, and therefore they usually shake less than the adjacent valleys underlain by alluvium. According to aftershock studies, sites in the Santa Monica Mountains experienced less than a one quarter of the strong ground shaking experienced by some sites in the adjacent San Fernando Valley that were severely damaged by the 1994 Northridge, California, Earthquake."

As the Nation's largest water, earth and biological science and civilian mapping agency, the USGS works in cooperation with more than 2000 organizations across the country to provide reliable, impartial, scientific information to resource managers, planners, and other customers. This information is gathered in every state by USGS scientists to minimize the loss of life and property from natural disasters, contribute to the sound conservation, economic and physical development of the Nation's natural resources, and enhance the quality of life by monitoring water, biological, energy and mineral resources.

To receive the latest USGS news releases automatically by e-mail, please send a request to listproc@listserver.usgs.gov. Please specify the listserver(s) of interest from the following list of names: water-pr; geologic-hazards-pr; biological-pr; mapping-pr; products-pr; lecture-pr. In the body of the message say subscribe (name of listserver)(your name). Example: subscribe water-pr joe smith.


Story Source:

The above story is based on materials provided by United States Geological Survey. Note: Materials may be edited for content and length.


Cite This Page:

United States Geological Survey. "Earthquakes Would Rattle Central United States." ScienceDaily. ScienceDaily, 29 May 1998. <www.sciencedaily.com/releases/1998/05/980529052117.htm>.
United States Geological Survey. (1998, May 29). Earthquakes Would Rattle Central United States. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/1998/05/980529052117.htm
United States Geological Survey. "Earthquakes Would Rattle Central United States." ScienceDaily. www.sciencedaily.com/releases/1998/05/980529052117.htm (accessed September 16, 2014).

Share This



More Earth & Climate News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Conservationists Face Uphill PR Battle With New Shark Rules

Conservationists Face Uphill PR Battle With New Shark Rules

Newsy (Sep. 14, 2014) New conservation measures for shark fishing face an uphill PR battle in the fight to slow shark extinction. Video provided by Newsy
Powered by NewsLook.com
Pakistan's 'killer Mountain' Fails to Draw Tourists After Attack

Pakistan's 'killer Mountain' Fails to Draw Tourists After Attack

AFP (Sep. 12, 2014) In June 2013, 10 foreign mountaineers and their guide were murdered on Nanga Parbat, an iconic peak that stands at 8,126m tall in northern Pakisan. Duration: 02:34 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins