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Pseudo-prospective forecasting of induced and natural seismicity in the Hengill geothermal field
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  • Vanille Ariane Ritz,
  • Leila Mizrahi,
  • Victor Clasen Repollés,
  • Antonio Pio Rinaldi,
  • Vala Hjörleifsdóttir,
  • Stefan Wiemer
Vanille Ariane Ritz
Swiss Seismological Service

Corresponding Author:vanille.ritz@sed.ethz.ch

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Leila Mizrahi
Swiss Seismological Service
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Victor Clasen Repollés
Swiss Seismological Service
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Antonio Pio Rinaldi
Swiss Seismological Service, Swiss Federal Institute of Technology (ETHZ)
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Vala Hjörleifsdóttir
Reykjavik Energy
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Stefan Wiemer
Swiss Seismological Service, ETH
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The Hengill geothermal field, located in southwest Iceland, is host to the Hellisheiði power plant, with its 40+ production wells and 17 reinjection wells. Located on a tectonically active area, the field experiences both natural and induced seismicity linked to the power plant operations. To better manage the risk posed by this seismicity, the development of robust and informative forecasting models is paramount. In this study, we compare the forecasting performance of a model developed for fluid-induced seismicity (the Seismogenic Index model) and a class of well-established statistical models (Epidemic-Type Aftershock Sequence). The pseudo-prospective experiment is set up with 14 months of initial calibration and daily forecasts for a year. In the timeframe of this experiment, a dense broadband network was in place in Hengill, allowing us to rely on a high quality relocated seismic catalogue. The seismicity in the area is characterised by four main clusters, associated with the two reinjection areas, one production area an area with surface geothermal manifestations but where no operations are taking place. We show that the models are generally well suited to forecast induced seismicity, despite some limitations, and that a hybrid ETAS accounting for fluid forcing has some potential in complex regions with natural and fluid-induced seismicity.
08 May 2023Submitted to ESS Open Archive
25 May 2023Published in ESS Open Archive