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Ryan C Cahalan, PhD

Ryan is a research geologist with the GMEG Science Center in Portland, Oregon. Since joining the USGS in 2020, Ryan has devoted his career to studying shallow geothermal energy and volcanic systems. Presently, his research focuses on modeling heat recovery in underground thermal energy storage (UTES).

Ryan Cahalan joined the USGS after completing a PhD at the University of Oregon on modeling multiphase transport in water-rich volcanic eruptions. His first project with the USGS was in collaboration with Cascades and Hawaiian Volcano Observatories, studying the December 2020 Kīlauea Volcano eruption focusing on the interaction of the erupted lava and the summit water lake. In November 2022, Ryan joined the Geothermal Resource Investigations Project (GRIP) where he applies his flow modeling background to new problems in underground thermal energy storage. Ryan is also the Powell Center Fellow for the City-scale Geothermal Energy Project.

Professional Experience

  • 2022 - Present, Research Geologist, Mendenhall Fellow, U.S. Geological Survey, Portland, Oregon

  • 2020 - 2022, RCUH Post-Doctoral Researcher, University of Hawaii-Hilo/U.S. Geological Survey, Cascades Volcano Observatory, Vancouver, Washington

Education and Certifications

  • Ph.D., Earth Sciences, University of Oregon, 2020

  • B.S. Geology, The University of Texas, 2012

Affiliations and Memberships*

  • 2012 - Present, American Geophysical Union

  • 2011 - Present, Geological Society of America

  • 2016 - Present, International Association of Volcanology and Chemistry of Earth's Interior

Honors and Awards

  • 2012 Outstanding Student Paper Award, American Geophysical Union

Science and Products

SUTRA Models Used to Evaluate Reservoir Thermal Energy Storage Performance in the United States

This data release documents eight 30-year SUTRA simulations summarized in Pepin and others (2025) and provides output from one short (1-year) simulation to provide verification that the model code runs properly. The most recent, but not-yet published, version of SUTRA (version 4.0) was used to evaluate reservoir thermal energy storage performance by simulating radially symmetric...
By
Colorado Water Science Center

Plumeria Simulations of 20 December 2020 Kīlauea Volcano Eruption Plume

This data release contains results of model simulations of a plume at Kilauea volcano that occurred on 20 December 2020. The ash-poor plume was produced when lava flowed into a water lake at the summit of Kilauea volcano. Simulations were conducted to constrain the conditions under which the plume rose to its observed height. The analysis and results are described in the accompanying...
By
Volcano Science Center

Reservoir thermal energy storage pre-assessment for the United States

Storing thermal energy underground for later use in electricity production or direct-use heating/cooling is a promising, viable, and economical green energy option. Reservoir thermal energy storage (RTES) is one such option, which stores energy in underutilized permeable strata with low ambient groundwater flow rates and more geochemically evolved (e.g. brackish/saline) waters relative...
Authors
Jeff D. Pepin, Erick R. Burns, Ryan Cain Cahalan, Daniel O. Hayba, Jesse E. Dickinson, Leslie L. Duncan, Eve L. Kuniansky
By
Colorado Water Science Center

Explosive 2018 eruptions at Kīlauea driven by a collapse-induced stomp-rocket mechanism

Explosive volcanic eruptions produce hazardous atmospheric plumes composed of tephra particles, hot gas and entrained air. Such eruptions are generally driven by magmatic fragmentation or steam expansion. However, an eruption mechanism outside this phreatic–magmatic spectrum was suggested by a sequence of 12 explosive eruptions in May 2018 at Kīlauea, Hawaii, that occurred during the...
Authors
Joshua Allen Crozier, Josef Dufek, Leif Karlstrom, Kyle R. Anderson, Ryan Cain Cahalan, Weston Thelen, Mary Catherine Benage, Chao Liang
By
Volcano Hazards Program, Geology, Minerals, Energy, and Geophysics Science Center, Volcano Science Center

Dynamics of the December 2020 ash-poor plume formed by lava-water interaction at the summit of Kilauea Volcano, Hawaii

On 20 December 2020, after more than 2 years of quiescence at Kīlauea Volcano, Hawaiʻi, renewed volcanic activity in the summit crater caused boiling of the water lake over a period of ∼90 min. The resulting water-rich, electrified plume rose to 11–13 km above sea level, which is among the highest plumes on record for Kīlauea. Although conventional models would infer a high mass flux...
Authors
Ryan Cain Cahalan, Larry G. Mastin, Alexa R. Van Eaton, Shaul Hurwitz, Adam B. Smith, Josef Dufek, Stephen A. Solovitz, Matthew R. Patrick, Jo Schmith, Carolyn Parcheta, Weston Thelen, Drew T. Downs
By
Volcano Hazards Program, Volcano Science Center

City-scale geothermal energy everywhere to support renewable resilience – A transcontinental cooperation

Cities have important and varying incentives to transform their energy sector to all-electric with low carbon emissions. However, they often encounter a number of impediments when attempting to implement such a change. For example, while urban areas have the highest energy demand-density, cities often lack the space for installing additional energy generation and/or long-duration energy...
Authors
Gregor Goetzl, Erick R. Burns, Andrew J. Stumpf, Yu-Feng Lin, Amanda Kolker, Maciej R. Klonowski, Cornelia Steiner, Ryan Cain Cahalan, Jeff D. Pepin
By
Water Resources Mission Area, Geology, Minerals, Energy, and Geophysics Science Center, John Wesley Powell Center for Analysis and Synthesis, New Mexico Water Science Center

Science and Products

*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government

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