Rupture directivity analysis data of hydraulic fracturing-induced seismic events in a shale gas field near Fox Creek, Alberta, Canada

This data repository contains the raw waveforms of seven hydraulic fracturing-induced seismic events, together with their rupture directivity analysis. The entire data is consolidated in one .mat file per seismic event (which can be read with Matlab and Octave). A detailed description of the .mat files, and a Matlab script to import and visualise the seismic data and rupture directivity analysis of each event, is also included in this repository. The passive seismic dataset was collected in a shale gas field near Fox Creek, Alberta, Canada, during a multi-stage hydraulic fracturing stimulation that induced shallow earthquakes (less than 5 km deep) of magnitudes up to 3.2. This area has experienced in recent years multiple cases on induced seismicity associated with oil and gas operations, including hydraulic fracturing and wastewater disposal, of magnitudes above 4.0 in some cases. The full passive seismic dataset was collected between October and November 2016 and made open source through a GitHub repository (https://github.com/ToC2ME). To determine the rupture directivity of each induced seismic event, we use the Empirical Green's Functions (EGF) method to first obtain apparent source time functions (ASTF), and then measure the rupture time at each seismic station. We then invert the rupture directivity of each seismic event based on the azimuthal variation of the measured rupture times at each seismic station. Observations of rupture directivity (the direction of propagation of the earthquake rupture) can provide important information as to the nature of the interactions between injection-induced pressure increases and earthquake nucleation. Measurement of rupture directivity could therefore have important implications for induced seismicity hazard management. The rupture directivity analysis of these hydraulic fracturing-induced seismic events was led and coordinated by Dr. James Verdon and Dr. Germán Rodríguez at the School of Earth Sciences, University of Bristol.