45. Groundwater Dynamics at an Active Stratovolcano

Groundwater and reactive magmatic volatiles play a pivotal role in various volcanic processes that pose significant hazards, from edifice collapse to explosive eruption.  Yet, there is little direct knowledge of the hydrogeology of active volcanoes.  Basic hydrogeological and geochemical parameters, such as water-table elevation, recharge and flow rates, residence times, volatile fluxes, and thermal parameters, critical for constraining hydrogeological models remain unknown.  The primary information we have regarding volcano hydrogeology comes from analysis of a single deep well at Kilauea Volcano (Hurwitz and others, 2002), from numerical modeling of groundwater and heat flow within a hypothetical stratovolcano (Hurwitz and others, 2003), from analyses of volcano seismicity hypothesized to be induced by seasonal groundwater recharge (for example, Christiansen and others, 2005), and from inferences obtained from aeromagnetic surveys (Finn and others, 2001).  Comprehensive analysis of volcano hydrogeology and its effects on volcanic processes is lacking, chiefly because few drill holes exist on or near active volcanoes; hence, less direct methods must be explored.  Springs can provide information on groundwater dynamics and volatile fluxes in regions lacking wells (Manga, 2001), and may provide essential data on volcano hydrogeology. At Mount St. Helens (MSH), numerous cold and hot springs surround the volcano and afford a superb opportunity to study 3D interactions of hydrogeological and volcanic processes.  Ongoing studies at MSH include analyses of these springs to characterize fluxes of magmatic volatiles and other components into groundwater to elucidate magmatic degassing.  Additional studies are needed to characterize recharge rates, flow paths, and physical properties such as volcano permeability and phase distribution.  These factors greatly influence magmatic heat transport, rock alteration, eruption explosivity, and the potential for volcanic mass-wasting.  Critical both to volcano-hazards and mineral-resource programs is an increased understanding of both volatile sources and the mechanisms for “scrubbing” (condensing and dissolving) volatiles into groundwater to produce hydrothermal fluids and rock alteration.

We seek a postdoctoral fellow to investigate the hydrogeology of Mount St. Helens using inferential methods and modeling, and to relate groundwater dynamics to volcanic processes.  In particular, we seek a scientist who can use innovative methods to constrain and couple groundwater dynamics with models that might address, for example, the fate of meltwater from the crater glacier; transport of magmatic gas and heat and its influence on magma ascent and explosivity; or the potential for large-scale mass wasting of the crater floor.  We especially encourage innovative uses of isotopic analyses (noble gases, CFCs, stable isotopes), geophysical surveys, and mathematical modeling relevant to an active volcano.  The Mendenhall Fellow will have the opportunity to work collaboratively with U.S. Geological Survey (USGS) scientists actively engaged in research on volcano hydrology and volcano hazards, and will have access to USGS chemical and isotope labs.  Research under this Opportunity would be a first step toward addressing groundwater dynamics and associated coupling with volcanic processes at this particular volcano, and has the potential to develop fundamental and transferable insights regarding active stratovolcanoes in general. 

References

Christiansen, L.B., Hurwitz, S., Saar, M.O., Ingebritsen, S.E., and Hsieh, P.A., 2005, Seasonal seismicity at western United States volcanic centers:  Earth and Planetary Science Letters, v. 240, p. 307–321.

Finn, C.A., Sisson, T.W., Deszcz-Pan, M., 2001, Aerogeophysical measurements of collapse-prone hydrothermally altered zones at Mount Rainier volcano:  Nature, v. 409, p. 600–603.

Hurwitz, S., Ingebritsen, S.E., and Sorey, M.L., 2002, Episodic thermal perturbation associated with groundwater flow: An example from Kilauea Volcano, Hawaii: Journal of Geophysical Research, v. 107. no. B11, p. 2297, doi:10.1029/2001JB001654.

Hurwitz, S., Kipp, K.L., Ingebritsen, S.E., and Reid, M.E., 2003, Groundwater flow, heat transport, and water table position within volcanic edifices: Implications for volcanic processes in the Cascade Range: Journal of Geophysical Research, v. 107, no. B12, 2557, doi:10.1029/2003JB002565.

Manga, M., 2001, Using springs to study groundwater flow and active geologic processes:  Annual Review of Earth and Planetary Sciences, v. 29, p. 201–228.

Proposed Duty Station: Menlo Park, CA; Vancouver, WA; Denver, CO

Areas of Ph.D.: Hydrology, volcanology, geochemistry, geophysics

Qualifications: Applicants must meet one of the following qualifications: Research Hydrologist, Research Geologist, Research Chemist, Research Geophysicist

(This type of research is performed by those who have backgrounds for the occupations stated above. However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)

Research Advisor(s): Steve Ingebritsen, (650) 329-4422, seingebr@usgs.gov; Jon Major, (360) 993-8927, jjmajor@usgs.gov; Bill Evans, (650) 329-4514, wcevans@usgs.gov; Shaul Hurwitz, (650) 329-4441, shaulh@usgs.gov; Gary Landis, (303) 236-5406, g_landis@usgs.gov

Human Resources Office contact: Candace Azevedo, (916) 278-9393, caazevedo@usgs.gov

Summary of Opportunities