Featured Research

from universities, journals, and other organizations

Fresh Look Inside Mount St. Helens

Date:
February 25, 2008
Source:
Michigan Technological University
Summary:
Volcanoes are notoriously hard to study. All the action takes place deep inside, at enormous temperatures. So geophysicists make models, using what they know to develop theories about what they don’t know. Geophysicists have just produced a new seismic model to help figure out what's going on deep inside Mount St. Helens, North America's most active volcano.

The most recent eruption of Mount St Helens began in October 2004 and is still going on.
Credit: Image courtesy of Michigan Technological University

Volcanoes are notoriously hard to study. All the action takes place deep inside, at enormous temperatures. So geophysicists make models, using what they know to develop theories about what they don’t know.

Related Articles


Research led by Gregory P. Waite, an assistant professor of geophysics at Michigan Technological University, has produced a new seismic model for figuring out what’s going on inside Mount St. Helens, North America’s most active volcano. Waite hopes his research into the causes of the earthquakes that accompany the eruption of a volcano will help scientists better assess the hazard of a violent explosion at Mount St. Helens and similar volcanoes.

Waite and co-authors Bernard A. Chouet and Phillip B. Dawson published their findings on February 19, 2008, in the Journal of Geophysical Research.

Volcanoes don’t always erupt suddenly and violently. The most recent eruption of Mount St Helens, for example, began in October 2004 and is still going on. It’s what Waite and other volcanologists call a passive eruption, with thick and sticky lava squeezing slowly out of the ground like toothpaste from a tube.

When a volcano such as Mount St Helens erupts, it can cause a series of shallow, repetitive earthquakes at intervals so regular that they’ve been called “drumbeat earthquakes.” Until now, scientists generally believed that these earthquakes were caused by the jerky movements of a solid plug of molten rock traveling up from the volcano’s core, a process known as the stick-slip model.

Modeling of seismic data collected by Waite and colleagues dispute that explanation. “The regularity and similarity of the shallow earthquakes seem consistent with a stick-slip model,” said Waite. Broadband measurements indicated that the energy is concentrated in a short bandwidth—between .5 and 2 Hz—and the earthquakes have nearly identical wave forms. Interestingly, the first motions observed at all of the seismic stations were the same.

“But this is not typical of a stick-slip event,” Waite said. “Rather, it suggests a source with a net volume change, such as a resonating fluid-filled crack.”

The fluid in the crack most likely is steam, derived from the magma and combined with water vaporized by the heat of the molten rock. A continuous supply of heat and fluid keeps the crack pressurized and the “drumbeats” beating, Waite explained.

“The pressurized crack in our model is filled with steam that could conceivably drive a small explosive eruption if the pattern (of earthquakes) we observe is disturbed,” he noted. Mount St. Helens erupted violently in 1980, losing nearly 1,000 feet of its cone-shaped top.

“The cause of Mount St. Helens earthquakes during the 2004-2008 eruption has been a matter of great debate,” said Seth Moran, the principal USGS seismologist monitoring the current eruption. “Greg collected a fantastic dataset with temporary seismometers and used highly sophisticated modeling techniques to produce a robust and intriguing model for the process responsible for those earthquakes. His model is somewhat different from the hypothesis that many other Mount St. Helens researchers have been using,” the seismologist went on to say, “and we are adjusting our understanding of the mechanics underlying the current eruption to incorporate his results.”

Waite’s research was conducted during a Mendenhall Postdoctoral Fellowship with the U.S. Geological Survey (USGS). Waite’s co-author, Chouet, who also works for the USGS, proposed a similar seismological model for volcanoes in Hawaii, where the lava is much more fluid and flows more easily. This is the first time the model has been applied to volcanoes like Mount St. Helens, with slow-flowing, sticky lava.


Story Source:

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


Cite This Page:

Michigan Technological University. "Fresh Look Inside Mount St. Helens." ScienceDaily. ScienceDaily, 25 February 2008. <www.sciencedaily.com/releases/2008/02/080219203516.htm>.
Michigan Technological University. (2008, February 25). Fresh Look Inside Mount St. Helens. ScienceDaily. Retrieved January 29, 2015 from www.sciencedaily.com/releases/2008/02/080219203516.htm
Michigan Technological University. "Fresh Look Inside Mount St. Helens." ScienceDaily. www.sciencedaily.com/releases/2008/02/080219203516.htm (accessed January 29, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Thursday, January 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Scientists Say Earliest Snakes Lived Alongside The Dinosaurs

Scientists Say Earliest Snakes Lived Alongside The Dinosaurs

Newsy (Jan. 28, 2015) Wrongly categorized as lizard fossils, snake fossils now show the reptile could have developed earlier than we thought — 70 million years earlier. Video provided by Newsy
Powered by NewsLook.com
Mobile Heat Tech the Google Maps of Energy Savings

Mobile Heat Tech the Google Maps of Energy Savings

Reuters - Innovations Video Online (Jan. 28, 2015) A Boston company has come up with a new and efficient way for homeowners to save money on energy costs, a timely innovation given the impact of this week&apos;s snow storms in the northeast US. The company is using a newly developed technology that can map heat signatures for entire cities in matter of days, generating data that could potentially produce billions in energy savings. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Time Lapse: Sculptures Created from 30 Tons of Snow

Time Lapse: Sculptures Created from 30 Tons of Snow

Rumble (Jan. 28, 2015) Students in North Finland use 30 tons of snow and one ton of ice to build a massive photography display and sculpture installation. Five days of work condensed into a one-minute time lapse! Video provided by Rumble
Powered by NewsLook.com
Scientists Hold Emergency Meeting to Save Endangered Rhinos

Scientists Hold Emergency Meeting to Save Endangered Rhinos

AFP (Jan. 28, 2015) Conservationists and scientists hold talks in Kenya to come up with a last ditch plan to save the northern white rhinoceros from extinction. Duration: 01:06 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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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