S016-01
RiskCat – a tool to simulate seismic hazard and risk for induced Seismicity

Tuesday, 8 December 2020: 17:32
Virtual
Corinne Elisabeth Layland-Bachmann, Lawrence Berkeley National Laboratory, Berkeley, CA, United States, William Foxall, Lawrence Berkeley National Laboratory, Earth and Environmental Sciences, Berkeley, CA, United States and Jean b Savy, SRC, Oakland, CA, United States
Recorded Presentation
Abstract:
The impact of fluid-induced seismicity has been increasing over the last several years, which has escalated the need to model the ongoing processes and forecast possible seismicity. To fully understand the regional consequences and communicate them to stakeholders and project operators, hazard and risk estimations need to be included in the forecast.

RiskCat is a tool to calculate probabilistic seismic hazard and risk that is accounting for non-stationarity in time. While conventional PSHA assumes stationary Poissonian processes, this cannot be presumed for rapidly changing conditions during fluid injection. Additionally, there isn’t a catalog of measured seismicity on which calculations can be based. RiskCat uses earthquake catalogs, simulated for induced seismic projects, and generates a catalog of ground motions for a set of specified sites and time windows. From these, it derives the probabilistic seismic hazard curves and nuisance curves for each site. Nuisance describes the probability that a person finds the ground-motion unacceptable and is a measure introduced for induced seismic hazard.

To determine the impact of an injection experiment, hazard and risk levels are compared to the background — i.e., before injection started — and they are calculated for the time during injection and again for predetermined times after the injection has ceased.

Here, we will present the simulations based on two different injection experiments. For both of those experiments, the injection and pore pressure diffusion were simulated using THOUGH2. We use two different methods for calculating the seismic catalogs from the simulated pore pressure diffusion; they vary in complexity and computational effort. We are using the seismic modeling code RSQsim and a simple geomechanical model. We present how the results of both of the seismic catalog simulations can be used as input to RiskCat and how we can determine the seismic hazard and risk levels at different times pre, post, and during injection.

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