Inferring fluid volume during earthquake swarms using seismic catalogues

Abstract

SUMMARY Many studies have pointed out a correlation between either the cumulative or the maximum seismic moment and the injected fluid volume when analysing global data sets of fluid injection-induced earthquake sequences. However, those correlations become quite uncertain when looking at individual episodes, mainly because of the large aseismic component of the induced deformation. If natural swarms are thought to result from the same physical processes as sequences from anthropogenic origin, little is still known about them as observations are limited by the depth of the active zone and the moderate deformations. In this work, we make profit of the similarity between both natural and injection-induced swarms. To this aim, we develop new relations between seismic observables and hydraulic attributes by using a global compilation of injection-induced earthquake catalogues, leading to two methods to estimate the injected fluid volume based solely on earthquake catalogues. Once the precision of our approaches is validated, we estimate the volume and flowrate of fluids circulating in diverse natural swarms, shedding a new light on the fluid dynamics that trigger them.