Summary of 2010 Madison Plateau, Yellowstone Earthquake Swarm

Map of Yellowstone National Park showing Jan-Feb, 2010 swarm earthquakes in
red, April, 2010 earthquakes in blue, previous swarms from 1995-2009 in green,
and volcanic vents with yellow stars. Caldera boundaries are shown in orange.
Mallard Lake Resurgent dome, to the southwest, and Sourcreek Resurgent dome,
to the northeast, are shown with yellow lines. The histogram at the top right shows
the number of earthquakes per day from January 15 to April 6, 2010. Image by
Jamie Farrell and Robert B. Smith (University of Utah), data from the University
of Utah Seismograph Stations. Click on the image for a full-size version.


Retrospective analysis shows that the 2010 Madison Plateau swarm began on January 15, 2010 with a few small earthquakes and picked up in intensity on the 17th of January. By the end of February 2010, earthquake activity at Yellowstone had returned to near-background levels, but activity has picked up somewhat in early April 2010. The swarm is located about 10 miles (16 km) northwest of the Old Faithful area on the northwestern edge of the Yellowstone Caldera. Swarms have occurred in this area several times over the past 30 years. Visual observation of landforms and geothermal features by Yellowstone National Park personnel did not show any changes that could be attributed to the earthquakes.

This swarm is now the second largest recorded swarm at Yellowstone. It was longer (in time) and included more earthquakes than last year's swarm beneath Yellowstone Lake (December '08/January '09). Calculations, by the University of Utah Seismology Research Group, of the total seismic energy released by all the swarm earthquakes corresponds to one earthquake with an approximate magnitude of 4.4. The largest recorded swarm at Yellowstone remains the Fall 1985 swarm, which was located in a similar location, in the NW corner of the Yellowstone Caldera.

As of April 6, 2010 a total of 2,347 earthquakes had been automatically located for the entire swarm, including 16 with a magnitude greater than 3.0; 141 with M2.0-2.9; 742 with M1.0-1.9; and 1,361 with M0.0-0.9. The largest events were a pair of earthquakes of magnitude 3.7 and 3.8 that occurred after 11 PM MST on January 20, 2010. Both events were felt throughout the park and in surrounding communities in Wyoming, Montana, and Idaho.


Aerial photo over the Madison Plateau looking south
towards the Teton Range. Most of the earthquakes in the
swarm were located beneath this area. During aerial
overflights, nothing remarkable or unusual was noted by
visible inspection or through use of an infrared camera.
Photo by Yellowstone National Park geologist Henry
Heasler during overflight on March 1, 2010.

See the University of Utah Seismograph Stations for the most recent earthquake data. Analysts continue to work through all the automatic earthquake locations, and are refining hypocenter locations, depths and magnitudes for inclusion in the earthquake catalog. As the events are refined, they are listed on the UUSS website and loaded into the ANSS catalog . Seismograph recordings are also available online by clicking on the station of interest on the Yellowstone seismograph network station map.

Swarms are common at Yellowstone

The number of earthquakes per day throughout the swarm was well above average at Yellowstone. Nevertheless, swarms are common at Yellowstone, with 100s to 1000s of events, some of which can reach magnitudes greater than 4.0. There were about 900 earthquakes during the December 2008 - January 2009 Yellowstone Lake swarm. The largest earthquake was a magnitude 3.9. The 1985 swarm, also on the northwest rim of the caldera but several miles from the current swarm, lasted for three months. During the 1985 swarm there were over 3000 total events recorded, with magnitudes ranging up to M4.9.

Although we give earthquake counts for previous swarms, it is not strictly correct to compare small differences in the number of earthquakes from one swarm to another. The number of earthquakes located depends on how close the earthquakes are to the monitoring equipment, the type and number of the seismometers in the network, and the software for analyzing the earthquakes. Our current monitoring capabilities allow for us to record many more earthquakes than we recorded in 1985, especially on the lower end of the magnitude scale. Even in the past year, the difference in the swarm locations and a change in software used to analyze the earthquakes makes it difficult to directly compare the earthquake count from last year's Yellowstone Lake Swarm to the current swarm. However, the earthquake count is still a useful number, especially for comparing the number of earthquakes from a swarm to other days during that year. To see the differences throughout the year in earthquake counts, please see Graphs of earthquake activity for the years 1994 to 2009.


Helicorder for Plate Boundary Observatory borehole seismometer B207, which is
about 7 miles (12 km) northeast of the 2010 swarm. Seismicity is shown for
January 17, 2010 through the Feb 8, 2010. Seismic data are provided by the
National Science Foundation funded Plate Boundary Observatory operated by
UNAVCO. Click on the image for a larger, more detailed version.

Seismologists continue to review the earthquakes

Earthquakes with magnitudes greater than 2.5 are automatically located and then automatically plotted on the University of Utah Map of Recent Earthquakes. The smaller events must be analyzed by a seismic analyst to determine what are correct earthquakes from that area. Because the smaller events need to be individually located, they are added to the map later than those that are automatically located. The delay in reporting the smaller earthquakes is usually not very noticeable, except when there are large numbers of very small earthquakes. The smaller earthquakes can be viewed on the University of Utah Yellowstone seismic network helicorders. Please keep in mind that all of the earthquakes will be analyzed but it will take time to get to the smaller ones.

To learn more about why seismologists need to review earthquakes see our new FrequentlyAsked Question, How are Yellowstone earthquakes analyzed and mapped? .


RSAM plot for PBO borehole seismometer B207 from January 17 to Feb 8, 2010. Real-time Seismic-Amplitude Measurement (RSAM) was developed
by the USGS to summarize seismic activity during heightened volcanic activity. For more information on RSAM see the Alaska Volcano Observatory's
RSAM page. Seismic data are provided by the National Science Foundation funded Plate Boundary Observatory operated by UNAVCO. Click on the
image for a larger version.

If you feel an earthquake, please report it

Many of the larger (> M 2.5) earthquakes have been felt in the Park and in the surrounding areas. If you feel earthquakes, please fill out a form on the USGS "Did You Feel It?" web site: http://earthquake.usgs.gov/eqcenter/dyfi/. Information collected from the form is used for scientific research. Maps are generated by the form information for each felt earthquake. For more information about what others have felt, see the shake map created by responses after the largest earthquake in the current swarm, a M3.8 on Wednesday, January 20, 2010 at 23:16.

We continue to monitor Yellowstone Volcano

YVO staff from the USGS, University of Utah, and Yellowstone National Park continue to carefully review all data streams that are recorded in real-time. 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. Yellowstone National Park is in a region of active seismicity associated with regional Basin and Range extension of the Western U.S., as well as volcanism of the Yellowstone volcanic field. Pressurization due to crustal magma bodies of the Yellowstone hotspot and associated shallow geothermal reservoirs can also contribute to earthquakes. Scientists continue to research the origin of these and other Yellowstone earthquakes. The USGS Volcano Alert Level and Aviation Color Code for Yellowstone remains at Normal and Green.

The Yellowstone Volcano Observatory (YVO) is a partnership of the U.S. Geological Survey (USGS), Yellowstone National Park, and University of Utah to strengthen the long-term monitoring of volcanic and earthquake unrest in the Yellowstone National Park region. Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park. YVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.

Other items of interest

Technical References