Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quake in Alaska changed Yellowstone geysers

28.05.2004


Some erupted more often, others less often after big jolt 2,000 miles distant



A powerful earthquake that rocked Alaska in 2002 not only triggered small earthquakes almost 2,000 miles away at Wyoming’s Yellowstone National Park – as was reported at the time – but also changed the timing and behavior of some of Yellowstone’s geysers and hot springs, a new study says.

"We did not expect to see these prolonged changes in the hydrothermal system," says University of Utah seismologist Robert B. Smith, a co-author of the study in the June issue of the journal Geology.


While other large quakes have been known to alter the activity of nearby geysers and hot springs, the Denali fault earthquake of Nov. 3, 2002, is the first known to have changed the behavior of such hydrothermal features at great distances, according to Smith and his colleagues. They say the magnitude-7.9 quake was one of the strongest of its type in North America in the past 150 years.

Smith conducted the study with Stephan Husen, a University of Utah adjunct assistant professor of geophysics who works at the Swiss Federal Institute of Technology; Ralph Taylor, an engineer who designs geyser monitoring equipment at Yellowstone National Park; and Henry Heasler, Yellowstone National Park’s geologist.

Less than 18 hours after the Denali earthquake in Alaska, Smith and colleagues at the University of Utah Seismograph Stations reported the major jolt had triggered more than 200 small earthquakes in Yellowstone – something widely reported by news media in the days following the quake.

Smith now says the triggered quakes at Yellowstone numbered more than 1,000 within a week of the Denali quake – if the count includes tiny temblors that were not "located," meaning their epicenters and depths were not determined. He says the quakes ranged in magnitude from minus 0.5 to just under 3.0. (Tiny quakes have negative magnitudes because modern seismic equipment can detect quakes smaller than was possible when the logarithmic magnitude scales were devised.)

Most of the triggered quakes were centered near geysers and hot springs.

Strong Earthquakes as Seismic and Geothermal Triggers

Scientists once believed that an earthquake at one location could not trigger earthquakes at distant sites. That belief was shattered in 1992 when the magnitude-7.3 Landers earthquake in California’s Mojave Desert triggered a swarm of quakes more than 800 miles away at Yellowstone, as well as other temblors near Mammoth Lakes, Calif., and Yucca Mountain, Nev.

The magnitude-7.5 Hebgen Lake, Mont., quake northwest of Yellowstone – a 1959 disaster that killed 28 people – triggered changes in Yellowstone’s geysers and hot springs, something not unexpected for a strong quake nearby.

Smith believes the Denali fault ruptured in such a direction – from northwest to southeast – that the brunt of its energy and its powerful surface waves were aimed southeast toward Yellowstone. As a result, the stresses rippling through the ground at Yellowstone were 200 to 300 times greater than if the Denali quake’s waves were aimed elsewhere, he says.

As the Denali quake’s surface waves arrived at Yellowstone, changes in hydrothermal activity first were noted at the 100 Spring Plain hot spring system in Norris Geyser Basin.

"Several small hot springs, not known to have geysered before, suddenly surged into a heavy boil with eruptions as high as 1 meter [about 39 inches]," Smith and colleagues wrote in Geology. "The temperature at one of these springs increased rapidly from about 42 to 93 degrees Celsius [about 108 to 199 degrees Fahrenheit]" and became much less acidic than normal. "In the same area, another hot spring that was usually clear showed muddy, turbid water."

Meanwhile, some geysers erupted more frequently than normal, while others erupted less frequently.

Yellowstone has more than 10,000 geysers, hot springs and fumaroles (steam vents), and scientists monitored how often 22 of the geysers erupted during the winter of 2002-2003. Eight of the 22 "displayed notable changes in their eruption intervals" after the Denali quake, 10 showed no significant changes and the other four were too erratic in the timing of their eruptions to determine if the quake changed them, the researchers wrote. Of the eight that changed:

-- Geysers that erupted more frequently following the Denali quake included Daisy, Depression, Plume and Riverside geysers in Upper Geyser Basin, and Pink Geyser in Lower Geyser Basin.

-- Geysers that erupted less frequently after the Denali quake included Castle and Plate geysers in Upper Geyser Basin and Lone Pine Geyser in West Thumb Geyser Basin.

Most geysers returned to their normal timing days to months after the Denali quake.

Oddly, geysers affected by earlier nearby earthquakes – most notably Old Faithful and Grand Geyser in Upper Geyser Basin – were not affected by the Denali earthquake.

How the Denali Quake Sparked Yellowstone Activity

Scientists do not know if the strong surface waves from the Denali quake independently triggered Yellowstone’s small quakes and changes in geyser activity. Smith suspects not. He believes the Denali quake’s waves affected the geysers by changing water pressure in underground conduits or "pipes" that feed the geysers. Such changes – which in some cases would have made hot water "flash" explosively into steam – would have altered the pressure on adjacent faults, triggering small earthquakes nearby. That would explain why the quakes were clustered around geyser basins.

Why did some geysers erupt more often and others less often? The researchers believe that when the Denali quake waves rippled through Yellowstone, they jarred loose minerals that had sealed some underground hot water conduits.

In some cases, that allowed superheated, pressurized water to flow more freely to make geysers erupt more often. In other cases, the rupturing of subterranean mineral seals enlarged the size of the conduits supplying geysers, reducing water pressure so those geysers erupted less often. Smith speculates that yet other geysers remained unchanged because they did not have pent-up gas and water pressure and were not affected by the Denali quake’s surface waves.

The Denali quake also generated noticeable water waves in Seattle’s Lake Union, Louisiana’s Lake Pontchartrain and in swimming pools on the East Coast. It also triggered small quakes in California’s Geysers geothermal area, which is north of San Francisco, and in eastern California’s Long Valley, which, like Yellowstone, is a caldera, or giant volcanic crater created by cataclysmic prehistoric volcanic eruptions.

The Denali quake also triggered a few small quakes in Utah, and Smith says it is possible some of those quakes occurred near little-known hot springs along the Wasatch fault at the base of the Wasatch Range.

Smith says the fact that the Denali quake triggered geyser and hot springs changes at Yellowstone raises an interesting question: "Could large earthquakes closer to Yellowstone trigger hydrothermal explosions?"

Such steam-and-hot water explosions in prehistoric times blasted out a hole that now is Mary’s Bay on Yellowstone Lake. One such explosion has occurred roughly every 1,000 years since the glaciers receded from Yellowstone roughly 14,000 years ago.

Smith says there is no evidence prehistoric quakes triggered those blasts. And such explosions were not triggered by the magnitude-7.5 Hebgen Lake, Mont., quake in 1959 or the magnitude-7.3 Borah Peak, Idaho, quake in 1983.

Nevertheless, a big quake near Yellowstone with its surface waves aimed the right way conceivably might "cause large hydrothermal eruptions," says Smith. "I would hypothesize that is certainly possible."


University of Utah Public Relations
201 S Presidents Circle, Room 308
Salt Lake City, Utah 84112-9017
(801) 581-6773 fax: 585-3350

Lee Siegel | University of Utah
Further information:
http://www.utah.edu/unews

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>