Earthquake hydrology
PhD opportunity at Victoria University of Wellington, with GNS Science
Supervisors
John Townend (Victoria University of Wellington), Simon Cox (GNS Science, Dunedin)
Collaborators
Caroline Holden, Charles Williams (GNS Science, Lower Hutt), Michael Manga (UC Berkeley), Helen Rutter (Aqualinc Research)
About
Earthquakes generate both static and dynamic (shaking) changes in stress and strain, which change fluid pressure and rock/sediment hydrologic properties and induce fluid flow, depending largely on the distance from an earthquake epicentre. Earthquake-related hydrologic responses, such as changes in the amount, direction, and rate of water flow in streams and in fluid pressure in the subsurface, are therefore not unexpected. What is perhaps surprising are the large amplitudes and great distances over which hydrologic responses have recently been shown to occur. Large earthquakes affect fluid pressures and have potential to trigger seismicity thousands of kilometres from earthquake epicentres. Although rare, hydrologic precursors involve similar physical principles and have the potential for earthquake prediction. Earthquake-induced fluid redistribution is also of great interest in earth science as it provides a principal mechanism for mineral deposit formation and fluids control the strength of shallow soil and faults.
We plan to fund a PhD to study hydrological effects during a series of recent, major earthquakes in the South Island of New Zealand, for the unique insight they provide on tectonic processes at spatial and temporal scales that are otherwise difficult to study. The New Zealand earthquakes were amongst the most densely instrumented on the planet in terms of monitoring networks for hydrogeology, geodetic surveying and broadband seismology. Continuous hydrological observations are available from throughout New Zealand, with over 250 bores monitored at 15 minute intervals, some sub-1 minute piezometers, and extensive river gauge networks. Hydrological responses included changes in groundwater level, increased river discharges and liquefaction - the latter of which was a prime reason for the extreme societal and monetary costs of the Canterbury earthquakes. The "hydroseismicity" dataset available for this study surpasses nearly all other international examples, comparable to the network that recorded the 1999 M7.6 Chi Chi earthquake in Taiwan that has become one of the most widely studied and cited events in earthquake hydrology.
The student will be part of a team funded by a Royal Society of New Zealand Marsden grant, international collaborators and other students actively examining hydrological effects of earthquakes. The PhD will be based in the School of Geography, Environment & Earth Sciences at Victoria University of Wellington ( http://www.victoria.ac.nz/sgees ), with extended visits to GNS Science offices in Dunedin and nearby Lower Hutt. The 2012 Performance Based Research Fund (PBRF) Quality Evaluation by the Tertiary Education Commission ranked Victoria University of Wellington number one in New Zealand for overall research quality and number one in New Zealand for research in geology and earth sciences. We envisage the successful applicant having a strong, quantitative background in earth science, geophysics and/or hydrology, with skills and experience in stress or hydrologic modelling, seismicity and mathematics. The PhD topic is likely to involve quantifying spatial variations in shaking, dynamic and static stresses, and their relationships to observed hydrologic responses. However, within the general context of this programme, the PhD topic is open and expected to reflect the motivation, skills and strengths of the successful applicant. The student will be funded to attend at least one international or local conference per annum, and is expected to make one research visit (3–6 weeks) to work with international colleagues. The PhD is fully funded for three years (NZ$25,000 stipend per annum + domestic fees).
The ideal start date for the PhD is 1 January 2014 or as soon as possible thereafter. Interested applicants should contact Simon Cox or John Townend by email for further information. Applications should be made via the Faculty of Graduate Studies of Victoria University of Wellington no later than 1 November 2013.