Induced Earthquakes from Long-Term Gas Extraction in Groningen, the Netherlands: Statistical Analysis and Prognosis for Acceptable-Risk Regulation

Charles Vlek*

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    20 Citations (Scopus)
    222 Downloads (Pure)

    Abstract

    Recently, growing earthquake activity in the northeastern Netherlands has aroused considerable concern among the 600,000 provincial inhabitants. There, at 3 km deep, the rich Groningen gas field extends over 900 km(2) and still contains about 600 of the original 2,800 billion cubic meters (bcm). Particularly after 2001, earthquakes have increased in number, magnitude (M, on the logarithmic Richter scale), and damage to numerous buildings. The man-made nature of extraction-induced earthquakes challenges static notions of risk, complicates formal risk assessment, and questions familiar conceptions of acceptable risk. Here, a 26-year set of 294 earthquakes with M 1.5 is statistically analyzed in relation to increasing cumulative gas extraction since 1963. Extrapolations from a fast-rising trend over 2001-2013 indicate thatunder business as usualaround 2021 some 35 earthquakes with M 1.5 might occur annually, including four with M 2.5 (ten-fold stronger), and one with M 3.5 every 2.5 years. Given this uneasy prospect, annual gas extraction has been reduced from 54 bcm in 2013 to 24 bcm in 2017. This has significantly reduced earthquake activity, so far. However, when extraction is stabilized at 24 bcm per year for 2017-2021 (or 21.6 bcm, as judicially established in Nov. 2017), the annual number of earthquakes would gradually increase again, with an expected all-time maximum M approximate to 4.5. Further safety management may best follow distinct stages of seismic risk generation, with moderation of gas extraction and massive (but late and slow) building reinforcement as outstanding strategies. Officially, acceptable risk is mainly approached by quantification of risk (e.g., of fatal building collapse) for testing against national safety standards, but actual (local) risk estimation remains problematic. Additionally important are societal cost-benefit analysis, equity considerations, and precautionary restraint. Socially and psychologically, deliberate attempts are made to improve risk communication, reduce public anxiety, and restore people's confidence in responsible experts and policymakers.

    Original languageEnglish
    Pages (from-to)1455-1473
    Number of pages19
    JournalRisk Analysis
    Volume38
    Issue number7
    DOIs
    Publication statusPublished - Jul-2018

    Keywords

    • Acceptable risk
    • earthquake safety
    • gas extraction
    • Groningen field
    • induced seismicity
    • INDUCED SEISMICITY
    • FLUID EXTRACTION
    • FACILITIES
    • INJECTION
    • RESERVOIR
    • INCREASE
    • ISSUES
    • FIELD

    Cite this