Featured Research

from universities, journals, and other organizations

Charting Seismic Effects On Water Levels Can Refine Earthquake Understanding

Date:
June 30, 2003
Source:
University Of Washington
Summary:
Just last November, the magnitude 7.9 Denali earthquake in Alaska was credited with sloshing water in Seattle's Lake Union and Lake Pontchartrain in New Orleans, and was blamed the next day when muddy tap water turned up in Pennsylvania, where some water tables dropped as much as 6 inches. But the relationship between seismic activity and hydrology is not well understood and is ripe for serious examination by scientists from the two disciplines, said David Montgomery, a University of Washington professor of Earth and space sciences.

Through many decades, stories about earthquakes raising or lowering water levels in wells, lakes and streams have become the stuff of folklore.

Just last November, the magnitude 7.9 Denali earthquake in Alaska was credited with sloshing water in Seattle's Lake Union and Lake Pontchartrain in New Orleans, and was blamed the next day when muddy tap water turned up in Pennsylvania, where some water tables dropped as much as 6 inches.

But the relationship between seismic activity and hydrology is not well understood and is ripe for serious examination by scientists from the two disciplines, said David Montgomery, a University of Washington professor of Earth and space sciences.

He and Michael Manga, associate professor of Earth and planetary science at the University of California, Berkeley, reviewed evidence of changes in stream flow and water levels in wells following earthquakes dating as far back as 1906, when a quake estimated at magnitude 7.7 to 7.9 struck San Francisco. Montgomery is an expert in surface hydrology and Manga is an expert in subsurface and aquifer hydrology.

The scientists found that, generally, an earthquake's effects on water depend on the distance from the epicenter, the magnitude and the geologic conditions at the location where changes to a well or stream are noted. They also found that effects on wells and aquifers were likely to be recorded at substantially greater distances from an earthquake's epicenter than are changes to stream flow.

"Put the two together and what it says is that the stream-flow response is a completely different beast than the water-well response," said Montgomery, lead author of a paper documenting the findings that is being published in the June 27 edition of the journal Science.

Montgomery said the new analysis provides a framework for understanding the broad range of earthquakes' effects on hydrology, and should help guide the study of links between seismology and hydrology.

Montgomery and Manga found that a mild earthquake, around magnitude 3, could generate effects on subsurface water, such as in wells, as far as about 10 miles from the epicenter. But effects on well water from a magnitude 9 quake could be observed more than 6,000 miles away. In fact, the latter scenario played out in the 1964 Alaska earthquake that registered 9.2.

"Wells in South Africa, clear on the other side of the world, responded," Montgomery said. "They didn't respond much, mind you, but the observations corresponded with the Alaska earthquake."

In examining changes in surface water related to seismic activity, the scientists found that the maximum distance from the epicenter at which effects were noted corresponded closely with theories about the maximum distance from the epicenter that liquefaction could be expected in an earthquake of the same magnitude. In addition, those maximum distances were far less than for subsurface water. For example, a magnitude 9 quake produced surface water changes only as far as about 750 miles from the epicenter. Montgomery noted that stream flow changes could be detected at much greater distances if they were, in fact, occurring that far away from the epicenter.

When an earthquake occurs, well-water levels can change as energy from the quake compresses the rock containing the water, thus forcing water out of its pores. Similarly, the flow of streams on the surface can increase as the aquifer is compressed, or either liquefies or settles during strong shaking, and water rises to the surface, Montgomery said.

"It's like squeezing a sponge because you're reducing the pore space and the water comes out. It has to go somewhere," he said.

Changes to surface and subsurface water could be related to each other at very close distances from the epicenter, Montgomery said, but even then different processes control them. That becomes more evident by the way they react at greater distances.

"One gives us a window on connections between hydrology, seismology and deformation of the Earth's crust," he said, "and the other gives us a better picture of connections between hydrology, seismology and geology at the surface."


Story Source:

The above story is based on materials provided by University Of Washington. Note: Materials may be edited for content and length.


Cite This Page:

University Of Washington. "Charting Seismic Effects On Water Levels Can Refine Earthquake Understanding." ScienceDaily. ScienceDaily, 30 June 2003. <www.sciencedaily.com/releases/2003/06/030627000320.htm>.
University Of Washington. (2003, June 30). Charting Seismic Effects On Water Levels Can Refine Earthquake Understanding. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2003/06/030627000320.htm
University Of Washington. "Charting Seismic Effects On Water Levels Can Refine Earthquake Understanding." ScienceDaily. www.sciencedaily.com/releases/2003/06/030627000320.htm (accessed April 20, 2014).

Share This



More Earth & Climate News

Sunday, April 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drought Concerns May Hurt Lake Tourism

Drought Concerns May Hurt Lake Tourism

AP (Apr. 18, 2014) Operators of recreational businesses on western reservoirs worry that ongoing drought concerns will keep boaters and other visitors from flocking to the popular summer attractions. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com
Ark. Man Finds 6-Carat Diamond At State Park

Ark. Man Finds 6-Carat Diamond At State Park

Newsy (Apr. 18, 2014) An Arkansas man has found a nearly 6.2-carat diamond, which he dubbed "The Limitless Diamond," at the Crater of Diamonds State Park. Video provided by Newsy
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