Peace River Induced Seismic Monitoring (PRISM) Nodal Seismic Array

Abstract

From 23 November 2022 to 30 November 2022, a sequence of earthquakes with a peak magnitude of ML 5.6 occurred ∼46 km away from Peace River—a vibrant rural community in Alberta, Canada. Broadly felt by residents throughout central Alberta, the ML 5.6 earthquake on 30 November 2022, registers as the second-largest earthquake ever reported in the Western Canada Sedimentary basin and possibly the largest Canadian earthquake induced by human activities. On 6 December 2022, 1 week after the mainshock, the University of Alberta and Alberta Geological Survey jointly installed a circular array of nodal geophones surrounding the seismogenic zone. Over the next 4 months, this quick-response array (nicknamed “Peace River Induced Seismic Monitoring” array, for short PRISM) operated at temperatures as low as −30°C and substantially bolstered the seismic data coverage in this previously undersampled region. Our preliminary array data analysis has detected more than 2000 earthquakes with magnitudes ranging from −1.9 to 5.0 since the initial outbreak in late 2022. Investigations based on earthquake location, focal mechanism, and magnitude jointly reveal distinct earthquake clusters distributed along pre-existing faults from earlier tectonic events. The data recovered from this array offer unique and vital constraints on the tectonic histories and seismic risks of the Peace River region.