SCEC Award Number 21149 View PDF
Proposal Category Collaborative Proposal (Data Gathering and Products)
Proposal Title Clay chemistry at earthquake timescales
Investigator(s)
Name Organization
Heather Savage University of California, Santa Cruz Randolph Williams University of Wisconsin, Madison Christie Rowe McGill University (Canada)
Other Participants Julia Krogh
SCEC Priorities 3d, 3f, 3c SCEC Groups FARM, SDOT, SAFS
Report Due Date 03/15/2022 Date Report Submitted 04/27/2022
Project Abstract
 Clay structure can be radically altered by heating during earthquakes, which could have a significant impact on fault strength, as well as a potential for recognizing structures that have experienced earthquake slip in the rock record. In this project, we aimed to quantify clay reaction kinetics when heated over a variety times and temperatures. Our initial results show that clays react at earthquake timescales and significant changes occur above temperatures of about 300 C.
Intellectual Merit Quantifying the kinetic reaction of clay dehydration is important for determining mechanical properties of faults coseismically. Also, if clay structure is permanently altered from seismic heating, such a change could be used as a paleoseismic indicator, which could extend our understanding of earthquake slip in complicated fault zones.
Broader Impacts This grant has supported UCSC grad student Julia Krogh. Studies of fault zone temperature rise during earthquakes has led to better understanding of what controls earthquake propagation and arrest.
Exemplary Figure Figure 1: Experiment 15A. The montmorillonite 001 (basal) peak narrows and increases in both 2θ and intensity.