Seismic Response of Hectometer‐Scale Fracture Systems to Hydraulic Stimulation in the Bedretto Underground Laboratory, Switzerland
Abstract We performed a series of hydraulic stimulations at 1.1 km depth in the Bedretto underground laboratory, Switzerland, as part of an overall research strategy attempting to understand induced seismicity on different scales. Using an ultra‐high frequency seismic network we detect seismic events as small as M w < −4, revealing intricate details of a complex fracture network extending over 100 m from the injection sites. Here, we outline the experimental approach and present seismic catalogs as well as a comparative analysis of event number per injection, magnitudes, b ‐values, seismogenic index and reactivation pressures. In our first‐order seismicity analysis, we could make the following observations: The rock volume impacted by the stimulations in different intervals differs significantly with a lateral extent from a few meters to more than 150 m. In most intervals multiple fractures were reactivated. The seismicity typically propagates upwards toward shallower depth on parallel oriented planes that are consistent with the stress field and seem to a large extent associated with preexisting open fractures. This experiment confirms the diversity in seismic behavior independent from the injection protocol. The overall seismicity patterns demonstrate that multi‐stage stimulations using zonal isolation allow developing an extended fracture network in a 3D rock volume, which is necessary for enhanced geothermal systems. Our stimulations covering two orders of magnitude in terms of injected volume will give insights into upscaling of induced seismicity from underground laboratory scale to field scale.
Authors
- Men‐Andrin Meier (ORCID: https://orcid.org/0000-0002-2949-8602)
- Nima Gholizadeh Doonechaly (ORCID: https://orcid.org/0000-0002-2281-8909)
- Luca Dal Zilio (ORCID: https://orcid.org/0000-0002-5642-0894)
- Linus Villiger (ORCID: https://orcid.org/0000-0002-0442-7963)
- Miriam Schwarz (ORCID: https://orcid.org/0009-0008-8579-508X)
- Domenico Giardini (ORCID: https://orcid.org/0000-0002-5573-7638)
- Stefan Wiemer (ORCID: https://orcid.org/0000-0002-4919-3283)
- Katrin Plenkers
- Hansruedi Maurer (ORCID: https://orcid.org/0000-0003-0131-1006)
- Florian Amann (ORCID: https://orcid.org/0000-0003-4849-5789)
- Xiaodong Ma (ORCID: https://orcid.org/0000-0003-3373-808X)
- Valentin Gischig (ORCID: https://orcid.org/0000-0002-0816-7361)
- Philipp Kästli (ORCID: https://orcid.org/0000-0001-8667-8549)
- Virginie Durand (ORCID: https://orcid.org/0000-0002-9380-5363)
- Antonio Pio Rinaldi (ORCID: https://orcid.org/0000-0001-7052-8618)
- Kai Bröker (ORCID: https://orcid.org/0000-0002-3074-8533)
- Anne Obermann (ORCID: https://orcid.org/0000-0001-6933-6301)
- Marian Hertrich (ORCID: https://orcid.org/0000-0001-9525-4609)
- M. Cocco (ORCID: https://orcid.org/0000-0001-6798-4225)
- Alba Zappone (ORCID: https://orcid.org/0000-0003-0965-7271)
- Paul Antony Selvadurai (ORCID: https://orcid.org/0000-0002-3846-8333)
- Mohammadreza Jalali (ORCID: https://orcid.org/0000-0002-9563-9645)
- Martina Rosskopf (ORCID: https://orcid.org/0009-0004-7156-4927)
- Jonas Simon Junker (ORCID: https://orcid.org/0009-0003-8630-1030)
Institutions
- Nanyang Technological University (SG)
- Istituto Nazionale di Geofisica e Vulcanologia (IT)
- ETH Zurich (CH)
- Earth Observatory of Singapore (SG)
- Swiss Federal Office of Energy (CH)
- University of Neuchâtel (CH)
- RWTH Aachen University (DE)
Publication Details
- Journal
- Journal of Geophysical Research Solid Earth
- Published
- 2024-11-01
- DOI
- https://doi.org/10.1029/2024jb029836
- Citations
- 17
- Primary Topic
- earthquake and tectonic studies
- Type
- article
- Field-Weighted Citation Impact
- 9.09
Funders
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- Eidgenössische Technische Hochschule Zürich