However, the rate of uplift has since slowed to a maximum of 4 centimeters per year, and the Yellowstone Volcano Observatory’s Website states, “At this time, there is no reason to believe that magma has risen to a shallow level within the crust or that a volcanic eruption is likely.” Computer models link the uplift to the recharging of the magma chamber about 10 kilometers (6 miles) below ground. For a time, the ground rose 7 centimeters per year (2.7 inches/year)-three times as fast as any rate in recorded history. The Yellowstone caldera began a period of accelerated uplift in 2004. Groundwater is heated to boiling by magma, and the heated water rises and expands, often explosively. A third earthquake trigger is the area’s well-known hydrothermal activity. In addition, the movement of magma more than 7 kilometers (4 miles) below ground causes other earthquakes. Numerous faults (locations traced by gray lines on the image) crisscross the area, and earthquakes occur when the ground moves along these faults. Geology at Yellowstone is complex, and earthquakes can have multiple causes. (People usually do not feel quakes that are smaller than magnitude 3.5, and magnitudes must generally reach 5.0 to damage buildings.) Magnitudes in this earthquake swarm ranged from 0 to 3.9. The swarm began in late December near Stevenson Island, and quake locations migrated north in the days that followed. Bigger dots indicate stronger quakes, and darker dots indicate earlier quakes. The size and color of the dots indicate magnitude and date. This image shows the topography of Yellowstone Lake and the location of quakes that occurred between December 29 and January 6. In the past forty years of monitoring, periodic swarms of small earthquakes, some reaching magnitudes greater than 4.0, have been the typical mode of activity at Yellowstone Lake. According to reports from the Yellowstone Volcano Observatory, this earthquake swarm is “well above typical activity at Yellowstone,” but it is not unprecedented. A quake of about this size that occurred in 1975 near Norris Geyser Basin was felt throughout the region.Įarthquakes cannot be predicted yet, but modern surveillance conducted with seismographs (instruments that measure earthquake locations and magnitudes) and Global Positioning System (GPS) instruments that measure slow ground movements help scientists understand the state of stress in the Earth's crust that could trigger earthquakes as well as magma movement.Between December 26, 2008, and January 6, 2009, several hundred small earthquakes rumbled beneath Yellowstone Lake in northern Wyoming. However, quakes within the caldera can be as large as magnitude 6.5. Geologists conclude that large earthquakes like the Hebgen Lake event are unlikely within the Yellowstone Caldera itself, because subsurface temperatures there are high, weakening the bedrock and making it less able to rupture. The majority of the damage occurred as a result of a large landslide that was triggered by the quake. Most recently, a devastating M w 7.3 (M s7.5) earthquake in 1959 killed 28 people and caused $11 million in damage (1959 dollars). This tectonic environment has created a series of regional faults that are responsible for large and devastating earthquakes in the Yellowstone region along the Teton and Hebgen Lake Faults. Each year, several earthquakes of magnitude 3 to 4 are felt by people inside and ouside the park.Īlthough rising magma and hot-ground-water movement cause some earthquakes, many occur as the result of Basin and Range extension of the western U.S. Public domain.)Īlthough most are too small to be felt, these quakes reflect the active nature of the Yellowstone region, one of the most seismically active areas in the United States. Visit Media to see details.Įarthquake damage from the 1959 Hebgen Lake event in the Yellowstone Plateau. (Credit: Hadley, J.
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