Unravelling the causes of the seismicity induced by underground gas storage at Castor, Spain - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue Geophysical Research Letters Année : 2021

Unravelling the causes of the seismicity induced by underground gas storage at Castor, Spain

Résumé

The offshore Castor Underground Gas Storage (UGS) project had to be halted after gas injectiontriggered three M4 earthquakes, each larger than any ever induced by UGS. The mechanisms thatinduced seismicity in the crystalline basement at 5-10 km depth after gas injection at 1.7 kmdepth remain unknown. Here we propose a combination of mechanisms to explain the observedseismicity. First, the critically stressed Amposta fault, bounding the storage formation, crept bythe superposition of well-known overpressure effects and buoyancy of the relatively lightinjected gas. This aseismic slip brought an unmapped critically stressed fault in the hydraulicallydisconnected crystalline basement to failure. We attribute the delay between induced earthquakesto the pressure drop associated to expansion of areas where earthquakes slips cause furtherinstabilities. Earthquakes occur only after these pressure drops have dissipated. Understandingtriggering mechanisms is key to forecast induced seismicity and successfully design deepunderground operations.
Fichier principal
Vignette du fichier
2020GL092038.pdf (1.62 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

insu-03172897 , version 1 (11-06-2021)

Licence

Paternité

Identifiants

Citer

Víctor Vilarrasa, Silvia de Simone, Jesus Carrera, Antonio Villaseñor. Unravelling the causes of the seismicity induced by underground gas storage at Castor, Spain. Geophysical Research Letters, 2021, 48 (7), ⟨10.1029/2020GL092038⟩. ⟨insu-03172897⟩
62 Consultations
48 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More