EOMF-02. Modeling the relationship between changing terrestrial water storage and seismicity

NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite mission aims to accurately measure changes in Earth’s gravity field. While this mission is useful for studying ocean currents, hydrologic processes and oceanic, glacial, and Earth mass changes, GRACE also can be used to study changes in groundwater storage (https://www.nasa.gov/mission_pages/Grace/overview/index.html). We will pair this data with geodetic and hydrologic datasets at higher spatial resolutions to better understand the effect of changes in terrestrial water storage (TWS) on earthquake occurrence and the associated time-dependent change in earthquake hazard (Gonzalez and Fernandez, 2011; Wahr et al., 2013; Borsa et al., 2014; Kraner et al., 2018). This will be done by utilizing gravity data from GRACE and GRACE Follow-On (GRACE-FO) to characterize the time-dependent gravity signal due to natural, seasonal, and anthropogenic changes in TWS, the associated mass changes, and model the resulting subsurface stress and strain. Here, we outline the initial methodologies used to assess this relationship and its effects on local and regional seismicity. We compile seismic data from both California and Greenland, and perform statistical analyses on these catalogues utilizing ZMAP. This software can be used to assess catalogue quality (including completeness and data artifacts), map seismicity rate changes, explore data interactively, and allow for fractal dimension analysis and stress tensor inversions (https://ui.adsabs.harvard.edu/abs/2001AGUFM.S42A0602W/abstract). These initial seismic datasets will serve as the cornerstone for our research moving forward.