******************************* USGS Postdoctoral opportunity ******************************* From: Jon Major <jjmajor@xxxxxxxx> The next cycle of the USGS Mendenhall Postdoctoral Research Fellowship Program provides an opportunity to study groundwater dynamics and its effects on volcanism at Mount St. Helens. A brief explanation of the opportunity is posted below. Delineating Groundwater Dynamics and its Effects on Volcanism at an Active Stratovolcano Groundwater plays a pivotal role in various volcanic processes that pose significant hazards. The potential, say, for slope failure, lahar generation, and phreatic eruption is strongly dependent on the position of the water table within a volcanic edifice and interactions of groundwater and magma. Transmission of fluid pressure, transport of mass and heat, and scrubbing of magmatic gasses are directly affected by groundwater position, abundance, and the time needed for water to advect through the system. Despite the importance of groundwater to volcano hazards, there is little direct knowledge of hydrogeology of active volcanoes. A comprehensive analysis of constrained hydrogeology and its effects on volcanic processes is lacking, chiefly because few drill holes exist on or near active volcanoes; hence, other methods are needed to gain insights on volcano hydrology. Springs can provide information on groundwater dynamics in regions lacking wells, and may be well-suited for studying volcano hydrogeology. At Mount St. Helens (MSH), numerous cold and hot springs surround the volcano at several elevations, and they afford an opportunity to study interactions of hydrogeological and volcanic processes at an active stratovolcano. Current studies at MSH include analyses of springs to examine fluxes of magmatic volatiles into groundwater to elucidate the character of the magmatic system. However, additional studies are needed to develop, at least to first order, a richer understanding of the volcano?s groundwater dynamics and potential interactions with volcanic processes. Processes such as recharge rates and flow paths, and properties such as volcano permeability and transmissivity greatly influence magmatic heat transport and the potential for mass-wasting within the volcano?s crater. We seek a postdoctoral fellow to investigate the hydrogeological system at MSH using inferential methods and modeling, and to relate its dynamics to volcanic processes. In particular, we seek a fellow who can utilize innovative methodologies for constraining groundwater dynamics and then coupling those dynamics with models that might address, for example, the fate of meltwater of the crater glacier, the transport of magmatic gas and heat and its influence on magma ascent and explosivity, or the potential for large-scale mass-wasting of the volcano?s crater floor. We especially encourage innovative uses of isotopic analyses (for example noble gases or CFC?s), geophysical surveys, and mathematical modeling that may be relevant to and appropriate for a challenging environment at an erupting volcano. The postdoctoral fellow will have the opportunity to work collaboratively with USGS scientists with diverse disciplinary backgrounds as well as with USGS state-of the-art chemistry labs. Details regarding this and other Mendenhall postdoctoral opportunities, and specifically the application process and deadlines, can be found at http://geology.usgs.gov/postdoc Questions regarding the specific opportunity described above can be directed to: Jon Major US Geological Survey Cascades Volcano Observatory jjmajor@xxxxxxxx ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
