Tuesday, January 19, 2010

Yellowstone hit by swarm of earthquakes

By Howard Pankratz, The Denver Post, h/t: The Daily Bail

Yellowstone National Park has been rattled by more than 250 earthquakes in the past two days following a period of 11 months of quiet seismic activity in the park.

The quakes have been gaining strength, with a 3.1 tremor recorded at 11:03 a.m. today. A 2.9 quake was recorded at 12:38 p.m.

Prof. Robert B. Smith, a geophysicist at the University of Utah and one of the leading experts on earthquake and volcanic activity at Yellowstone, said that the activity is a "notable swarm."

"The swarm is located about 10 miles northwest of Old Faithful, Wyo., and nine miles southeast of West Yellowstone, Montana," said Smith.

Jamie Farrell, a doctoral student in geophysics who works with Smith at the University of Utah, said that as of 3 p.m. today, 270 quakes have been recorded in the past two days.

Farrell said the quakes are occurring in an area about 5 miles from where the largest swarm of quakes was ever recorded in October 1985.

Quakes in the current swarm have ranged in magnitude of 0.5 to 3.1.

Farrell said there have been reports of at least one of the tremors being felt in the park, but he is expecting more reports as the earthquakes continue.

Smith said such swarms are "relatively common." Today's tremors seem to be normal tectonic activity, and is "not an indication" that some sort of volcanic activity will occur.

Since 1995 there have been 80 swarms, including the one that started Sunday, Farrell said.

Farrell said that there is absolutely no connection between what is occurring in Yellowstone and the magnitude 7.0 earthquake in Haiti.

"They are completely different systems," said Farrell. "They are not related."

In late December 2008 and early January 2009, Yellowstone National park experienced the second largest earthquake swarm in Yellowstone's recorded seismic history. The swarm under the north end of Yellowstone Lake consisted of 813 earthquakes with magnitudes ranging up to 3.9.

The most devastating earthquake in recent history in the Yellowstone region occurred on Aug. 17, 1959, when a magnitude 7.3 earthquake hit. It was centered near Hebgen Lake, Mont., killed 28 people and caused more than $11 million in damage.

Mike Stickney, director of earthquake studies at the Montana Bureau of Mines and Geology, said there is no way to predict when the next big one will hit.

He said it will likely occur along one of the 45 faults that line two belts - one stretching from Yellowstone National Park up to Helena, Mont., and a second one along the Montana-Idaho border.

The Yellowstone Plateau is one of the largest super-volcanoes in the world and has gone through three volcanic cycles spanning two million years, which included some of the world's largest known eruptions.

Seismic imaging was used by University of Utah scientists to construct this 3-D picture of the Yellowstone hotspot plume of hot and molten rock that feeds the shallower magma chamber (not shown) beneath Yellowstone National Park, outlined in green at the surface, or top of the illustration. The Yellowstone caldera, or giant volcanic crater, is outlined in red. State boundaries are shown in black. The park, caldera and state boundaries also are projected to the bottom of the picture to better illustrate the plume's tilt. Researchers believe "blobs" of hot rock float off the top of the plume, then rise to recharge the magma chamber located 3.7 miles to 10 miles beneath the surface at Yellowstone. The illustration also shows a region of warm rock extending southwest from near the top of the plume. It represents the eastern Snake River Plain, where the Yellowstone hotspot triggered numerous cataclysmic caldera eruptions before the plume started feeding Yellowstone 2.05 million years ago. Image credit: University of Utah.

Related: Recent Earthquakes in the Intermountain West - Yellowstone National Park Special Map [most recent quake map]

Yellowstone's Plumbing Reveals Plume of Hot and Molten Rock 410 Miles Deep [molten rock map story]

3 comments:

covertress said...

Rather than being triggered by lava-flow murmurings deep in the Yellowstone Caldera, the latest quakes are believed to be the result of shifting plate tectonics, according to a statement issued by the Yellowstone Volcano Observatory (YVO), which is operated by the University of Utah and the U.S. Geological Survey. "At this time the Yellowstone Volcano Observatory does not consider the swarm to be unusual and the earthquakes are likely related to tectonic fault sources," the statement said. "Also there is no indication of premonitory volcanic or hydrothermal activity, but ongoing analyses will evaluate these different sources." -- TIME

Michael said...

If Yellowstone were to blow, it would devestate our country in everyway.

So, if scientists really believed that Yellowstone were to blow, would it be disclosed to a population of 300 million ?

I don't think so.

covertress said...

I agree, Michael.

Monitor the latest Yellowstone Region Press Releases here.

BTW, it seems that the Intermountain West map is not being updated today (23-Jan-10). You can view the real-time data for this swarm here.