I am looking for candidates for this fully funded Post-doc project which is using samples from IODP Expedition 362.
Aim is to to characterize micro-fabrics and pore structures of core samples, using Broad Ion Beam polishing and (cryogenic) Scanning Electron Microscopy.
A short description of the project is below.
The position will be open until filled.
Please forward to anyone who might be interested and contact me for any further information.
Prof. Dr. Janos L. Urai
Structural Geology, Tectonics and Geomechanics
RWTH Aachen University, Lochnerstrasse 4-20
D-52056 Aachen, Germany
T: +49 241 809 5723 e-mail: [log in to unmask]
www.ged.rwth-aachen.de
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2 year fully funded Post-Doctoral position, RWTH Aachen University
Deformation mechanisms in sediments entering a subduction complex to shallow seismogenic slip
Janos L. Urai – RWTH Aachen University, Germany
Project description
Earthquakes challenge our ability to predict, yet doing so remains keenly important for risk mitigation in modern society. With increasing awareness of the rich variety of seismic events, from massive, destructive earthquakes like the 2004 Sumatra earthquake to slow-slip quakes, the imperative to understand potential geologic controls increases. These objectives motivated IODP Expedition 362 to drill and sample the Bengal/Nicobar Fan sequence and sediments down to the Indian Ocean basaltic crust in order to characterize the materials that will enter the subduction zone and will contribute to an end-member earthquake. The Sumatra earthquake is of special interest because it occurred closer to the trench than expected, increasing earthquake and tsunami size (Simon et al., 2011). A recent paper (Hüpers et al., 2017) shows that the shallow slip offshore Sumatra is driven by diagenetic strengthening of deeply buried fault-forming sediments associated to complete dehydration of silicates before subduction, contrasting with conventional models.
To contribute to the better understanding of this atypical shallow seismogenic slip, we propose to characterize micro-fabrics and pore structures of core samples, partly frozen in LN2 on site during this expedition in order to (1) look for anomalies in microstructure that when combined with seismic and physical property data might define future fault localization and decollement horizons and (2) deformation mechanisms during compaction and small-scale faulting that will help extrapolate mechanical properties of rocks from their current seaward location into the Sumatra subduction complex. To fulfill these objectives, we will investigate progressively compacted and mildly deformed samples preserved on site in cryogenic conditions (i.e. no drying damage and preservation of pore water) and more numerous slowly dried samples, using (cryogenic) Broad Ion Beam polishing and (cryogenic) Scanning Electron Microscopy. We will compare these results with microstructures of core samples for which the stress-strain path is measured in the laboratory, to test hypotheses about how the sedimentary section will respond to additional burial and shear stress when entering the subduction complex.
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