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Investigation of Spatiotemporal Variations in the Magnitude Distribution of Induced Seismicity Due to Natural Gas Production in the Groningen Field

Description: 

Production of natural gas from the Groningen gas field in the Netherlands causes induced earthquakes that have already led to many cases of building damage and also pose a personal safety threat to the local population. To enhance public safety and mitigate damage claims, the gas production has recently been strongly reduced to a minimal level that is still required for (meteorological/geopolitical) security of supply. Also, even after production stop, seismicity is expected to continue, for example due to pressure equilibration. As a result, seismic hazard and risk assessment remains relevant for the near future .
As a part of our efforts to improve hazard and risk forecasts, we perform statistical analyses on spatiotemporal patterns in the magnitude distribution of the Groningen earthquake catalogue, which contains 336 earthquakes with above M=1.45, observed in the period between 1 January 1995 and 1 January 2022.
An exploratory moving-window analysis of maximum-likelihood b-values exposes significant variations in space, but not in time. In search for improved understanding of the observed spatial variations in physical terms we test a number of physical reservoir properties as possible b-value predictors. The predictors include static (spatial, time-independent) properties such as the reservoir thickness and the topographic gradient (a measure of the degree of faulting intensity in the reservoir) as well as dynamic (spatiotemporal, time-dependent) properties such as the pressure drop due to gas extraction, the reservoir compaction, and a measure for the induced stress development.
We assess the predictive capabilities of the static and dynamic predictors by statistical evaluation of both moving window analysis, and maximum-likelihood parameter estimation for a number of simple functional forms that express the b-value as a function of the predictor. We find significant trends of the b-value for topographic gradient and induced stress, but even more pronouncedly for reservoir thickness.

Session: Opportunities and Challenges in Source Modeling for Seismic Hazard Analysis

Type: Oral

Date: 4/20/2023

Presentation Time: 10:15 AM (local time)

Presenting Author: Dirk A. Kraaijpoel

Student Presenter: No

Invited Presentation: 

Authors