Science Spotlight

Station WLWY

Researcher: Christine Puskas

In college I was introduced to tectonics and the ice ages and the long and fascinating history of the Earth.

Site WLWY is at the northeastern end of Yellowstone's massive caldera.

Name: WLWY EBRY WY1999
State: WY
Country: United States
Elevation: 2643.2 m
Lat/Long:  44.6395 / -110.2867

Yellowstone Volcano

When will Yellowstone erupt?

This is a question on many people's minds. Yellowstone is one of the largest volcanoes in the world, and a major eruption would affect not only the whole country, but also the entire planet.

Is Yellowstone still active? Signs point to yes. Its activity is apparent through its many geysers and thermal springs, small but frequent earthquakes, and motion recorded by GPS instruments.

Station WLWY is located at the northeastern end of the Yellowstone caldera, near the most active part of Yellowstone's volcanic system. In late 2004, the ground at WLWY started to rise at rates of up to 7 cm/yr—much faster than previously measured rates of 0-2 cm/yr. WLWY was the first Yellowstone station to start rising, and the fastest, indicating that the uplift started in the northeast caldera. The entire caldera rose in a period of uplift that lasted until 2010. In 2010, the motion leveled out and then turned to subsidence. Instead of an eruption, the uplift episode produced two large earthquake swarms. We do not know whether a magmatic intrusion occurred, but the uplift episode demonstrated Yellowstone's volcanic system is still active.

Many rapid uplift (and subsidence) episodes have occurred since the last great eruption 640,000 years ago, but it is only recently with the installation of a permanent GPS network that we can observe these episodes as they happen.

To explore geophysical monitoring at Yellowstone, check out Yellowstone Volcano Observatory's Monitoring page.

Figure 1. Volcanic and hydrothermal activity in the Yellowstone area is fueled by a large reservoir of magma (partially molten rock) beneath a caldera (volcanic depression) that formed in a cataclysmic eruption 640,000 years ago. The magma reservoir includes both rhyolitic magma, rich in silica (SiO2), and basaltic magma, which contains less SiO2 and is denser. Scientists think the 1985 earthquake swarm shown here was caused by escaping hydrothermal fluids. (Credit: USGS)

Figure 3. The Gray Lakes Tributary in the Yellowstone basin. Thermal springs are one of the indications that Yellowstone is still active. (Credit: Jacob Lowenstern, USGS)


Figure 2. GPS velocity vectors for 2008-2009 are shown in white (horizontal) and red (vertical). The colors on the map show uplift calculated from another method, called InSAR. InSAR provides a detailed picture of the spatial pattern of deformation, while GPS has better temporal sampling. (Credit: Chang et al., 2010, via University of Utah)

Figure 4. Position changes for WLWY in a North America fixed reference frame. (For help interpreting the graphs, see the GPS Data page.)

Spotlight Questions

  • Looking at the motion of WLWY in Figure 4, can you identify one or more time periods when the Yellowstone caldera was "inflating"? When it was deflating?
  • Imagine what might be going on inside the volcano when it inflates and deflates. What are some possible causes of this motion?
  • How might changes in the magma reservoir affect the Yellowstone hydrothermal system?
  • Look at the station photo for WLWY. What are some possible reasons for installing the GPS antenna so high off the ground?
  • Classroom exercise: Taking the Pulse of Yellowstone's Breathing Volcano: Problem-Based Learning in America's First National Park

Last modified: 2019-12-26  16:24:49  America/Denver  


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