The Jellystone Jiggle
I had no idea that Yellowstone's volcano was as magmatically and seismically active as it is. Strange as it may seem, I find it fascinating. 15,000 earthquakes between 1973 and 1998? That's way cool! Luckily, given that Yellowstone is a park, I doubt there are many permanent dwellings there, and they have been adding a lot of monitoring equipment:"The Yellowstone observatory consists of a string of 28 electronic detection stations scattered through the park. Related plans call for at least 100 more monitoring sites."
And if statist Californians can get used to earthquakes, surely rugged Porcupines can handle them too.
From Yellowstone Volcano: Is "the Beast" Building to a Violent Tantrum?
August 30, 2001
The Earth has always shaken periodically around Yellowstone. But without the proper monitoring equipment in place, no one knew how often it happened or why. [Robert Smith, a geophysicist at the University of Utah], who has been investigating here for more than 30 years, set up seismometers and found earthquakes by the hundreds.
...the earthquakes Smith started tracking three decades agoâ€”15,000 between 1973 and 1998, often in swarmsâ€”didn't altogether fit conventional notions of seismicity. ....
"It was not a surprise it was a young volcano," [Robert Christiansen of the U.S. Geological Survey] recalled. "It was a surprise it was as young as it is." [Christiansen was the Scientist-in-Charge of the Mount St. Helens monitoring effort during the 1980 eruption.]
....Together, the two men were able to see the system for what it was: a very active and large volcano that had sculpted much of the Northwest.
In the mid-1970s, while surveying an old benchmark put into place when the first roads were cut through Yellowstone in 1923, Smith found that the ground had risen three feet (one meter) in five decades.
There could be only one explanation. The volcano was bulging upward.
Christiansen doubts the likelihood of another cataclysmic eruption any time soon, but he doesn't rule out something smaller. Earthquakes, rock slides, and steam explosions from geyser basins are all possible. A blowout on the scale of Mount St. Helens is conceivable, he said, adding: "We need to be prepared." YELLOWSTONE EARTHQUAKES (1983-Present)http://www.seis.utah.edu/HTML/YPEvents1983-Pres.html
From August 2003 Yellowstone Seismicity Summaryhttp://volcanoes.usgs.gov/yvo/monitoring.html
During the month of August 2003, 101 earthquakes were located in the Yellowstone region. The largest shock to occur during this report period was a magnitude 4.3 earthquake on August 21st at 07:46 UTC, located about 23.3 miles south southeast of West Thumb, Wyoming and 9 miles southeast of the south entrance to Yellowstone National Park.
From Yellowstone Volcano Observatory Established
U.S. Geological Survey, Yellowstone National Park and the University of Utah Partnership
May 14, 2001 http://www.seis.utah.edu/recactivity/yvorelease.shtml
The Yellowstone National Park and surrounding area encompass the largest active magmatic system in North America.
The Yellowstone region is seismically active. The 1959 Hebgen Lake earthquake (surface-wave magnitude 7.5), centered just outside the Park's northwestern boundary was responsible for 26 of the quake's 28 deaths. This event is one of the 15 strongest earthquakes ever recorded in the contiguous U.S.
"While the active geologic processes at Yellowstone do impart some risk to the public, they also make it a unique treasure -- it is the volcanic and seismic energy that powers the geysers and hot springs, creates the mountains and canyons, and generates the unique ecosystems that support Yellowstone's diverse wildlife," notes Paul K. Doss, Yellowstone National Park Coordinating Scientist of YVO
From When will Yellowstone erupt again? http://volcanoes.usgs.gov/yvo/faqs4.html
We do not know. Future volcanic eruptions could occur within or near Yellowstone National Park for the simple reason that the area has a long volcanic history and because there is hot and molten rock, or magma, beneath the caldera now. Yellowstone is monitored for signs of volcanic activity by YVO scientists who detect earthquakes using seismographs and ground motion using GPS (Global Positioning System). YVO has not detected signs of activity that suggest an eruption is imminent.
Yellowstone's 2-million-year history of volcanism, the copious amount of heat that still flows from the ground, the frequent earthquakes, and the repeated uplift and subsidence of the caldera floor also testify to the continuity of magmatic processes beneath Yellowstone and point to the possibility of future volcanism and earthquake activity.