EGS Collab Experiment 1: In-situ observation of pre-, co- and post-seismic shear slip preceding hydraulic fracturing
- Lawrence Berkeley National Laboratory
Understanding the initiation and arrest of earthquakes is one of the long-standing challenges of seismology. Here we report on direct observations of borehole displacement by a meter-sized shear rupture induced by pressurization of metamorphic rock at 1.5 km depth. We observed the acceleration of sliding, followed by fast co-seismic slip and a transient afterslip phase. Total displacements were about 7, 5.5 and 9.5 micrometers, respectively for the observed pre-slip, co-seismic slip and afterslip. The observed pre-slip lasted about 0.4 seconds. Co-seismic slip was recorded by the 1 kHz displacement recording and a 12-component array of 3-C accelerometers sampled at 100 kHz. The observed afterslip is consistent with analytical models of arrest in a velocity-strengthening region and subsequent stress relaxation. The observed slip vector agrees with the activation of a bedding plane within the phyllite, which is corroborated by relocated seismic events that were observed during the later stages of the injection experiment. This submission includes the pressure and deformation data recorded by the SIMFIP probe during the first injection at the 164 ft (50 m) notch of borehole E1-I. The injection was performed on on 05/22/2018 as part of Experiment 1 of the EGS Collab project. This data accompanies a manuscript submitted to GRL, linked in this submission.
- Research Organization:
- DOE Geothermal Data Repository; Lawrence Berkeley National Laboratory
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Geothermal Technologies Program (EE-4G)
- Contributing Organization:
- Lawrence Berkeley National Laboratory
- OSTI ID:
- 1768008
- Report Number(s):
- 1289
- Availability:
- GDRHelp@ee.doe.gov
- Country of Publication:
- United States
- Language:
- English
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EGS Collab Experiment 1: SIMFIP Notch-164 GRL Paper
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Related Subjects
E1-I
EGS
EGS Collab
SIMFIP
SURF
Sanford Underground Research Facility
afterslip
axial
borehole
borehole displacement
co-seismic
deformation
displacement
energy
fracturing
geothermal
hydraulic
in-situ
injection test
post-seismic
pre-slip
pressure
probe
seismic
shear
slip
slip vector
stimulation