Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Charting seismic effects on water levels can refine earthquake understanding

27.06.2003


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."



For more information, contact Montgomery at 206-685-2560 or dave@ess.washington.edu; or Manga at 510-643-8532 or manga@seismo.berkeley.edu

Vince Stricherz | EurekAlert!
Further information:
http://www.washington.edu/

More articles from Earth Sciences:

nachricht Sediment from Himalayas may have made 2004 Indian Ocean earthquake more severe
26.05.2017 | Oregon State University

nachricht Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>