Nanoscale insight into the dynamic strength of fault surfaces during and after an earthquake

During an earthquake, transient friction-generated heat can affect how minerals deform and thus the strength of the fault. Thin (0.1–1 mm-thick) mirror-like slip surfaces (fault mirrors) that form during earthquake processes and record evidence of coseismic temperature rise are thus ideal materials to investigate how the deforming volume of rock evolves over individual or multiple earthquake cycles. Here we present atom probe tomography (APT) data from two hematite fault mirrors that were collected from the footwall damage zone of the Wasatch fault zone (Utah, USA). These samples provide evidence of the nanoscale response of minerals to earthquake rupture and yield new insights about the dynamic evolution of fault strength throughout the earthquake cycle.

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Presenter:


Emily M. Peterman, PhD
Associate Professor of Earth and Oceanographic Science
Bowdoin

Dr. Emily Peterman is a geoscientist who obtained her BA from Middlebury College and her PhD from the University of California, Santa Barbara in the USA. She pursued postdoctoral research at the University of California, Santa Cruz and Stanford University before assuming her current role as an associate professor at Bowdoin College in Maine, USA. Dr. Peterman's research program focuses on investigating the impact of micro- and nano-scale processes on crustal-scale tectonism and the evolution of lithosphere strength. Her research methodology involves combining field, laboratory, and modeling work across different spatial and temporal scales. She specializes in analyzing mineral chemistry and crystal microstructure to determine the processes, conditions and timing of mineral (re)crystallization. Dr. Peterman has recently undertaken projects utilizing atom probe tomography to examine trace element segregations in both naturally occurring and experimentally treated minerals.