Yellowstone Monthly Update issued Mar 3, 2014

Since late summer 2013, the Yellowstone GPS network has tracked a small ground deformation episode in north-central Yellowstone National Park. During the past five months, the NRWY GPS station has recorded about 3.5 cm (1.4 in) of uplift and about 1 cm (0.4 in) of southeastward ground movement, relative to a stable reference station north of the Park. Measurements from other GPS stations in northern Yellowstone show smaller displacements, forming a circular pattern of deformation consistent with a minor pressurization, about 6 to 10 km (4-6 miles) deep, near Norris Junction.

Similar patterns of ground deformation have occurred before in this part of Yellowstone. From 1996 through 2003 the Norris Geyser Basin rose about 12 cm, before beginning to subside in 2004. More information about this event is available at http://volcanoes.usgs.gov/volcanoes/yellowstone/yellowstone_monitoring_51.html.

Episodes of ground deformation, which occur commonly in Yellowstone and at other dormant volcanoes around the world, pose no direct volcanic hazards, nor do they imply that an eruption is pending. They do, however, create a scientific opportunity to better understand the geologic processes at work in Yellowstone and elsewhere. YVO and other scientists are pursuing this opportunity, and will continue to monitor the ground deformation closely.

UNAVCO, a YVO member agency, operates the Yellowstone GPS network.The Yellowstone Volcano Observatory (YVO) provides long-term monitoring of volcanic and earthquake activity 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.

YVO Member agencies: USGS, Yellowstone National Park, University of Utah, University of Wyoming, UNAVCO, Inc., Wyoming State Geological Survey, Montana Bureau of Mines and Geology, Idaho Geological Survey

The ground deformation occurring in north-central Yellowstone, which we reported in an Information Statement on February 18, 2014, continues. In March, YVO plans to deploy several additional GPS instruments to learn more about this scientifically interesting deformation episode. Caldera subsidence, which began in 2010, appears to be slowing. All the deformation currently occurring in Yellowstone remains well within historical norms.

During February 2014, the University of Utah reports 245 earthquakes were located in the Yellowstone National Park region. February seismicity in Yellowstone was marked by an ongoing cluster of 153 earthquakes, located about 5 miles WNW of Norris Geyser Basin, YNP, that persisted throughout the month. The cluster included the largest event of the month, which was a minor earthquake of magnitude 3.5 on February 11, 2014 at 4:03 PM MST.

Although seismicity over Yellowstone as a whole is only slightly above normal, seismicity levels in the deforming region in the north-central part of the Park have increased since the deformation began. This correlation is neither worrisome nor surprising since ground deformation and small earthquakes often occur together.

Please see: http://volcanoes.usgs.gov/observatories/yvo/YVO_GPS.jpg for a map of GPS stations in Yellowstone. For a graph of daily GPS positions at NRWY, a station about 1.5 miles SE of Norris Geyser Basin, please see: http://pbo.unavco.org/station/overview/NRWY. For GPS positions at WLWY, near White Lake in the northeastern part of Yellowstone caldera, please see: http://pbo.unavco.org/station/overview/WLWY.The Yellowstone Volcano Observatory (YVO) provides long-term monitoring of volcanic and earthquake activity 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.

YVO Member agencies: USGS, Yellowstone National Park, University of Utah, University of Wyoming, UNAVCO, Inc., Wyoming State Geological Survey, Montana Bureau of Mines and Geology, Idaho Geological Survey