USGS / NATIONAL PARK SERVICE HYDROTHERMAL RESEARCH AND MONITORING IN THE VOLCANO PARKS

For over half a century, the USGS and the NPS have collaborated on hydrothermal studies in parks that encompass active volcanoes. Collaborations initiated by the NPS are often related to resource assessment and management issues; recent examples include studies at Bering Land Bridge National Preserve, Devils Postpile National Monument, Hawaii Volcanoes NP, and Yellowstone NP. Collaborations initiated by the USGS are motivated by the need to assess geothermal resources and by the USGS mandate to monitor active volcanoes, assess their hazards, and on occasion issue “timely warnings” (Public Law 93-288); recent examples include studies at Lassen Volcanic NP, Mount Rainier NP, and Yellowstone. The Forest Service (e.g. in the Cascades and eastern California) and Fish & Wildlife Service (e.g. in the Aleutians) also manage active volcanic landscapes, and in fact exposure of the US population to near-field volcanic hazards is minimized by the fact that most of our ~170 active volcanoes are under Federal land management that restricts permanent surface occupancy; we have few “cities on volcanoes”. The study of hydrothermal fluids is of interest in the context of volcanic hazard because they can destabilize volcanic edifices, act as propellant in steam-driven explosions, and transport potentially toxic gases. Further, hydrothermal systems act to modulate or even cause the seismic and geodetic signals that constitute our primary volcano-monitoring data. Ongoing USGS / NPS hydrothermal studies can serve multiple purposes. For instance, the nearly 50-year-long continuous Cl-flux record from the Yellowstone hydrothermal system is relevant to understanding both volcano dynamics and the impact of climate variability. Similarly, ongoing geyser studies contribute both to better understanding of eruption processes (the geyser as analog system) and to monitoring geyser activity in the context of climate variability and human development. Recently expanded hydrothermal studies at Lassen were prompted by the California drought, in light of record levels of fumarolic superheat observed during the 1976-77 drought. The USGS and the land-management agencies share cultural values (e.g. multidecadal perspectives) and common goals (e.g. public safety) that facilitate sustained and successful collaboration in this arena.