14-3. Go with the flow: linking geophysical constraints on alteration and water in volcanoes to numerical models of slope stability and hydrologic processes
Catastrophic flank collapse of steep stratovolcanoes may induce volcanic eruptions, generate lahars, or trigger tsunamis that threaten lives around the world (e.g. Kerle and others, 2003; Carrasco-Núñez and others, 2006; Silver and others, 2009; Cortés and others, 2010). Mapping and three-dimensional (3D) analysis to define collapse-prone areas of volcanoes is one of the USGS Natural Hazards Science Strategy priorities (Holmes and others, 2012), because several volcanoes along the Cascade Range and in Alaska that rank as top priority volcanoes in the USGS National Volcano Early Warning System (http://volcanoes.usgs.gov/publications/2009/nvews.php.)have experienced catastrophic flank collapses during the Holocene.
A primary control on the stability of the flanks is the position of the water table within the volcanic edifice and the interactions of groundwater with ascending magmatic gases. Transmission of fluid pressure and the transport of mass and heat are directly affected by groundwater position, abundance, and flow rates within the edifice and groundwater interaction with acid magmatic gases can lead to rock alteration and the formation of mechanically weak rocks prone to failure (Reid and others, 2001). Recent applications of airborne (Finn and others, 2001, 2007) and ground based (Bedrosian and others, 2007; Aizawa and others, 2009;Revil and others, 2011) geophysical methods provide inference about groundwater distribution within specific stratovolcanoes and numerical models of multiphase groundwater flow and heat transport provide insight into the parameters controlling groundwater pressure distribution within an edifice (Hurwitz and others, 2003; Reid, 2004). Nevertheless, multidisciplinary studies are needed to link geophysical observations with modeling efforts to better understand groundwater circulation patterns in stratovolcanoes and the effects of mechanically weak altered rocks on volcano flank stability.
We seek a postdoctoral fellow with strong quantitative skills to elucidate and develop the linkages between geophysical imaging of the interior of volcano edifices, characterization of water distribution and rock shear strength properties, and the hydrologic processes triggering massive edifice instability. The proposed research lies at the intersection of geophysics, hydrology, and volcanology. We anticipate that the candidate will utilize innovative approaches to leverage existing USGS high-resolution 3Dgeophysical data from stratovolcanoes in the Cascade Range (Mounts Rainier, Adams, Baker, and St. Helens) and Alaska (Iliamna Volcano) with numerical models that couple groundwater flow, heat transport, rock mechanics, and/or reactive transport(e.g. Taron and others, 2009).This approach has the potential to significantly improve our understanding of the processes that lead to flank collapse, lahar generation, and phreato-magmatic eruptions. Some fundamental questions that might guide this effort include:
Aizawa, K., Ogawa, Y., Ishido, T. (2009) Groundwater flow and hydrothermal systems within volcanic edifices: delineation by electric self-potential and magnetotellurics, J. Geophys.Res., 114, B01208.doi:10.1029/2008JB005910.
Bedrosian, P.A., Unsworth, M.J., Johnston, M.J.S. (2007) Hydrothermal circulation at Mount St. Helens determined by self-potential measurements, J. Volcanol. Geotherm. Res., 160, 137-146.
Carrasco-Núñez, G., Diaz-Castellon, R., Siebert, L., Hubbard, B., Sheridan, M. F., Rodriguez, S. R., (2006) Multiple edifice-collapse events in the Eastern Mexican Volcanic Belt: The role of sloping substrate and implications for hazard assessment, J. Volcanol. Geotherm. Res., 158, 151-176.
Cortés, A., Macías, J.L., Capra, L., Garduño-Monroy, V.H. (2010) Sector collapse of the SW flank of Volcán de Colima, México. The 3600yr BP La Lumbre-Los Ganchos debris avalanche and associated debris flows, J. Volcanol. Geotherm. Res., 197, 52-66.
Finn, C.A., Sisson, T.W., Deszcz-Pan, M., (2001) Aerogeophysical measurements of collapse-prone hydrothermally altered zones at Mount Rainier volcano, Nature, 409, 600-603.
Finn, C.A., Deszcz-Pan, M., Anderson, E.D., John, D.A. (2007) Three-dimensional geophysical mapping of rock alteration and water content at Mount Adams, Washington: Implications for lahar hazards, J. Geophys.Res., 112, art.no. B10204.
Holmes, R. R. Jr., Jones, L. M., Eidenshink, J. C., Godt, J. W., Kirby, S. H., Love, J. J., Neal, C. A., Plant, N. G., Plunkett, M. L., Weaver, C. S., Wein A., and Perry, S. C., (2012) Natural hazards science strategy, U.S. Geol. Surv.Open-File Rep. 2012–1088, 75 p.
Hurwitz, S., Kipp, K.L., Ingebritsen, S.E., Reid, M.E. (2003) Groundwater flow, heat transport, and water table position within volcanic edifices: Implications for volcanic processes in the Cascade Range, J. Geophys. Res., 108, ECV 1-1 - ECV 1-19.
Kerle, N., van Wyk de Vries, B., Oppenheimer, C. (2003) New insight into the factors leading to the 1998 flank collapse and lahar disaster at Casita volcano, Nicaragua, Bull. Volcanol., 65, 331-34.5
Reid, M.E. (2004) Massive collapse of volcano edifices triggered by hydrothermal pressurization, Geology, 32, 373-376.
Reid, M.E., Sisson, T.W., Brien, D.L. (2001) Volcano collapse promoted by hydrothermal alteration and edifice shape, Mount Rainier, Washington, Geology, 29, 779-782.
Revil, A., Finizola, A., Ricci, T., Delcher, E., Peltier, A., Barde‐Cabusson, ., Avard, G., Bailly, T., Bennati, L., Byrdina, S., Colonge, J., Di Gangi, F., Douillet, G., Lupi, M., Letort, J., Tsang Hin Sun, E. (2011) Hydrogeology of Stromboli volcano, Aeolian Islands (Italy) from the interpretation of resistivity tomograms, self-potential, soil temperature and soil CO2 concentration measurements,Geophys. J. Inter., 186, 1078-1094.
Silver, E., Day, S., Ward, S., Hoffmann, G., Llanes, P., Driscoll, N., Appelgate, B., Saunders, S. (2009) Volcano collapse and tsunami generation in the Bismarck Volcanic Arc, Papua New Guinea, J. Volcano. Geotherm. Res., 186, 210-222.
Taron, J., Elsworth, D., Min, K.-B.(2009) Numerical simulation of thermal-hydrologic-mechanical-chemical processes in deformable, fractured porous media Inter. J. Rock Mech. Min. Sci., 46, 842-854.
Areas of Ph.D.: Volcanology, geophysics, hydrology, rock mechanics, soil mechanics, numerical modeling, geothermal energy, or related fields (candidates holding a Ph.D. in other disciplines, but with extensive knowledge and skills relevant to the Research Opportunity may be considered).
Qualifications: Applicants must meet one of the following qualifications - Research Geologist, Research Geophysicist, Research Hydrologist, Research Physicist, Research Mathematician.
(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 theposition will be made by the Human Resources specialist).
Proposed duty stations: Menlo Park, CA; Denver, CO
Research Advisors: Shaul Hurwitz, (650) 329-4441, firstname.lastname@example.org.; Mark Reid, (650) 329-4891, email@example.com.; Josh Taron, (650) 329-4940, firstname.lastname@example.org.; Paul Bedrosian (303) 236-4834, email@example.com.; Carol Finn, (303) 236-1345, firstname.lastname@example.org.
Human Resources Office Contact: Jennifer Daberkow, (303) 236-9566, email@example.com
|Summary of Opportunities|