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Caldera Chronicles

Caldera Chronicles is a weekly article written by U.S. Geological Survey Yellowstone Volcano Observatory scientists and colleagues.

May 21, 2018 Article Link

Way to go, Idaho…Geological Survey!

Yellowstone Caldera Chronicles is a weekly column written by scientists and collaborators of the Yellowstone Volcano Observatory. This week's contribution is from Zach Lifton, geologist with the Idaho Geological Survey.

As you know, the Yellowstone Volcano Observatory is made up of 8 separate agencies that work together to monitor and understand the Yellowstone volcanic system. These agencies include the state geological surveys of Montana, Wyoming, and Idaho. Today, we'll take a closer look at the mission of the Idaho Geological Survey (IGS)—the lead state agency for the collection, interpretation, and dissemination of geologic and mineral resource data for Idaho since 1919.

Geologic map of the volcanic rocks of Idaho (Click image to view full size.)
Volcanic rocks of Idaho, based on the Geologic Map of Idaho.

The IGS is a non-regulatory state agency that is administered as a Special Program of the University of Idaho. In addition to the main office on University of Idaho's Moscow campus, the Survey has a southern branch office in Boise. The agency is staffed by approximately 12 state-funded, full-time employees and 15 externally-funded, temporary and part-time employees.

The Survey's goal is to provide the state with timely and relevant geologic information, and to privde the public with transparent access to those data. The IGS accomplishes its goals through applied geologic research and strong collaborations with federal and state agencies, academia, private sector partnerships, community service, and educational outreach activities.

The IGS has programs in geologic hazards, hydrogeology and groundwater, geothermal energy, oil and gas, minerals and economic geology, mining record compilations, and earth science educational outreach. As Idaho grows, demand is increasing for geologic information related to population, energy, mineral, and water resource development, and geologic hazards such as landslides and active faults with accompanying earthquakes.

As a member of the YVO consortium, the IGS collaborates on monitoring of regional volcanic activity. In fact, Idaho has a long history of spectacular volcanism. Much of central Idaho is made of Idaho Batholith granite (approximately 65-100 million years old) and Challis Volcanic rocks (approximately 40-50 million years old). Western Idaho is covered by huge volumes of Columbia River basalts (approximately 17 million years old), and southern Idaho is made of lava erupted along the Yellowstone hotspot track. The youngest volcanic rocks in Idaho, located at Craters of the Moon National Monument, are only 2,000 years old. Those lava flows erupted from a series of cracks called the Great Rift volcanic zone, which could produce more lava flows in the future.

Landsat image of young lava flow at Craters of the Moon National Monument (Click image to view full size.)
Young lava flows at Craters of the Moon National Monument, Idaho. NASA Earth Observatory image by Robert Simmon, based on Landsat data from the USGS Global Visualization Viewer. Accessible online here.

One of the legacies of Idaho's volcanic history is abundant geothermal activity and numerous hot springs. In the 1890s, the City of Boise created the first municipal geothermal heating system in the nation, which heated over 200 buildings. Boise's geothermal system is still functioning and heats many downtown buildings, including the State Capitol.

In addition to volcanic hazards, the IGS also studies and monitors landslides and earthquakes around the state. The IGS maintains landslide and active fault databases, which are currently being revised and updated. In late 2017, a sequence of over 2,000 earthquakes occurred near Soda Springs, Idaho. The largest of these earthquakes was magnitude 5.3 and was felt across the region. However most of the earthquakes around Soda Springs were too small to feel. These earthquakes were part of the normal tectonic activity in southeastern Idaho and were not related to volcanic activity in Yellowstone.

The experience of IGS with volcano, earthquake, and landslide hazards adds important capabilities to YVO's mission in the Yellowstone region!