Thursday, March 24, 2011

Shakin’ All Over by Marie D. Jones & Dr. John M. Savino Ph.D.


Yellowstone, Supervolcanoes and Mega Quakes – Any Connections?

With all eyes on Japan and the catastrophic 9.0 Sendai quake that devastated the nation, many in the U.S. have wondered about possible links between mega earthquakes and recent upheavals of the caldera floor at the mighty Yellowstone supervolcano. The general question is - could a mega earthquake such as the 2010 Chilean 8.8 or the Sendai event possibly trigger seismic activity on a fault or beneath a volcano at distances of thousands of miles including on the other side of the planet?

There is good news, and there is bad news. The good news first. The seismic network that monitors activity in and around the Yellowstone supervolcano shows no significant increase in background seismicity during the week following the magnitude 9.0 Japan earthquake.

The bad news is, there is so much scientists still have yet to learn about what makes mega quakes and supervolcanic eruptions occur when they do. While current research indicates possible links between global seismic activity, as well as links between large earthquakes and seismic activity beneath volcanic zones, predictions of when mega earthquakes or major volcanic eruptions will occur remain an elusive goal.


In our book Supervolcano: The Catastrophic Event That Changed the Course of Human History, we documented new research by a number of sources, including USGS scientists, scientists from the Carnegie Institution, and from the Institute of Geophysics and Planetary Physics at the Scripps Institute in La Jolla, CA (see pages 199-205). These studies noted several instances where seismic activity was triggered beneath volcanoes by the passage of seismic surface waves generated by large earthquakes that originated thousands of miles from the volcanoes.

A press release by the University of Utah in 2002 described two cases involving Yellowstone
***November 4, 2002 -- A major, magnitude-7.9 earthquake that rocked Alaska on Sunday apparently triggered scores of earthquakes some 2,000 miles away at Yellowstone National Park in Wyoming. By 8:30 a.m. MST Monday Nov. 4 - about 17 hours after the Alaskan quake - more than 200 small earthquakes had been detected occurring in clusters throughout the Yellowstone area. The quakes were recorded by the Yellowstone seismic network operated by the University of Utah Seismograph Stations. The smallest events were of magnitude less than 0 and the largest of about magnitude 2.5. National Park Service rangers at Old Faithful and Canyon Village reported feeling some of the earthquakes. While the data are preliminary, they suggest that the Yellowstone earthquakes may have been triggered by the passage of large seismic waves generated by the Alaskan earthquake more than 3,200 kilometers (almost 2,000 miles) from the park. The apparent triggering is suggested by the fact the Yellowstone activity began within a half hour of the Alaska earthquake, which hit at 3:12 p.m. MST Nov. 3 (1:12 p.m. local time in Alaska). There also are preliminary reports the Alaska quake may have triggered smaller tremors at The Geysers geothermal area in northern California. Scientists once believed that an earthquake at one location could not trigger earthquakes at distant sites. But 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 jolts near Mammoth Lakes, Calif., and Yucca Mountain, Nev. The apparent triggering of the Yellowstone tremors by the Alaska quake "confirms what we are beginning to see worldwide - that earthquakes can be triggered by other earthquakes at great distances, more so than we had thought before," said Robert. B. Smith, a University of Utah professor of geology and geophysics and coordinating scientist for the Yellowstone Volcano Observatory. Clusters of small earthquakes in time and space are common in Yellowstone. However, the clusters of Yellowstone earthquakes following the Alaskan mainshock extended across much of the park and were not concentrated in a single location. The small Yellowstone quakes are not considered to pose a threat to the public, but are of great interest to scientists who want to confirm if they were triggered and understand how. Investigation is ongoing and may take some time to complete, said Sue Nava, seismograph network manager at the University of Utah Seismograph Stations. There has been some suggestion that seismic waves from a large, distant quake may jostle the ground at Yellowstone, triggering small quakes by moving the hydrothermal fluids responsible for Yellowstone geysers and hot springs.***


In SuperVolcano, we focused mainly on the Southern San Andreas fault and the potential of a mega quake there triggering a supereruption at the nearby Long Valley caldera, which to this day remains, in our opinion, worth watching as much as Yellowstone. Yet the studies we cited also suggested that even Yellowstone was close enough to the Southern San Andreas, approximately 770 miles away, to potentially be influenced by a major quake.

There has been research into whether quakes at the edge of one tectonic plate can trigger second quakes at different locations and times. In the January 31st issue of “Nature,” a team of researchers from Penn State University, California Institute of Technology and the University of California, Santa Cruz looked at two large quakes that occurred near Japan in late 2006 and early 2007. The team, led by Penn State associate professor of geoscience Charles J. Ammon, found that the first quake on November 15th 2006, a magnitude 8.3 on the edge of the Pacific plate thrusting under the arc of the Kuril Islands, may have influenced a second magnitude 8.1 quake that occurred sixty days later, in January of 2007, in the upper portion of the Pacific plate, thus producing one of the largest recorded shallow extensional quakes.

Though the team did not find direct cause, they labeled this a “doublet,” two earthquakes that are linked by the sequence of seismic activity. “Such large doublet earthquakes, though rare, could be an underestimated hazard,” Ammon stated in a story for Science Daily in February of 2008. “Within minutes of the Nov. 15 quake, seismic activity began on the Pacific plate in the area where the January earthquake would take place,” Ammon continued.

Another Science Daily story in December of 2008 showed links between L-waves, the slow moving seismic surface waves produced by large quakes, and smaller quakes. Seismologists led by Kris Pankow, assistant director of the University of Utah seismic stations in Salt Lake City, Utah, looked at how these L-waves cause smaller quakes as they travel along the ground. The team followed 15 large quakes and found that 12 of them did indeed trigger smaller quakes. They distinguished these smaller quakes from aftershocks because of the time and proximity.

In 2004, scientists monitoring Yellowstone caldera began to see the ground above the caldera rise upward at rates as high as 2.8 inches a year. Though the rate did slow between 2007 and 2010 to just a centimeter a year or less, ground levels over the volcano were raised up by up to 10 inches, or 25 centimeters, at some points around the caldera. University of Utah’s Bob Smith, quoted in the press release above, stated in National Geographic in January of 2011 that the uplift was extraordinary, but went on to state that these kinds of uplifts, which occur when magma reservoirs four to six miles below the surface of the caldera floor surge, do happen and have happened over thousands of years without an eruption. Ground deformation can indeed be a precursor to an eruption, as magma moves towards the surface. This did happen in the months before the 1980 eruption of Mount St. Helens.

But it doesn’t always happen. The story also quotes Smith as saying, “Based on geologic evidence, Yellowstone has probably seen a continuous cycle of inflation and deflation over the past 15,000 years, and the cycle will likely continue.”

Predicting a supereruption is quite difficult, because we have no written records of what exactly happens before it does occur. Continuous records at Yellowstone alone have been available only since the 1970s. The last supervolcanic eruption occurred in New Zealand over 26,500 years ago. Unfortunately for scientists, there was nobody around with a laptop taking notes of exactly what happened in the days, weeks and months before.

Large quakes have been found to have a link to caldera uplift and deformations, but as Smith concludes, “How those intrusions stress the adjacent fault, or how the faults might transmit stress to the magma system, is a really important new area of study.”

In the meantime, the USGS makes available, via the Internet, the constant monitoring of the two main calderas we in the United States should be concerned with – Yellowstone and Long Valley, California. One can easily pull up the recent status reports and updates for the Yellowstone Volcanic Observatory and the Long Valley Observatory (go to http://volcanoes.usgs.gov) and see the current volcanic alert levels, quake activity, ground deformation and any other pertinent information.

And so for the good news…As of this week, all activity at both monitoring stations was normal. Yellowstone volcanic alert level: Normal. Earthquake activity continuing at normal levels. Ground deformation shows that the period of accelerated caldera uplift HAS STOPPED. Long Valley alert level is also Normal, with some small quake activity under 1.5 since March 11th of 2011. Deformation is showing minor fluctuations in uplift and subsidence, but remains roughly 80 cm higher than in the late 1970s. Diffuse carbon dioxide gas flux in the Horseshoe Lake tree-kill area has shown little change from relatively high levels of 50 to 150 tons per day, the sustained rate over last few years. Tree-kill is another potential clue to supervolcanic eruptions.

That doesn’t mean something won’t happen. Nobody was prepared for Japan’s 9.0. But it does mean that, for now, we can focus on the disasters at hand as we continue important research into the ones we hope never happen.

Dr. John Savino, Ph.D. is a geophysicist with a background in earthquakes and volcanoes. He has assisted the Department of Energy (DOE) in reviewing research conducted by earth scientists at several national laboratories and universities. Dr. Savino has also participated in the DOE’s Public Outreach Program, delivering presentations on earthquakes and volcanoes. He has presented papers at numerous scientific conferences and published articles in refereed journals, technical reports, and abstracts in conference and meeting programs. He lives in Big Bear Lake, California.

Marie D. Jones is the author of SuperVolcano, PSIence, 2013, 11:11 The Time Prompt Phenomenon, The Resonance Key, Deja Vu Enigma, Trinity Secret and Destiny vs. Choice. She lives in San Marcos, California.

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