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EGS Collab Experiment 1: In-situ observation of pre-, co- and post-seismic shear slip preceding hydraulic fracturing
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.
Resources
2 resources available
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Shear Event Experiment 1.csv
CSV -
EGS Collab Experiment 1 SIMFIP Notch-164 GRL Paper
HTML
Complete Metadata
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|---|---|
| accessLevel | public |
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"fn": "Yves Guglielmi",
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| description | 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. |
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"description": "Pressure data from 05/22/2018 recorded by the SIMFIP probe during the first injection at the 164 ft (50 m) notch of borehole E1-I.
NOTE: Opening this file in Microsoft Excel will lead to data loss because the file is longer than Excel's maximum allowed number of rows."
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"title": "EGS Collab Experiment 1 SIMFIP Notch-164 GRL Paper",
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"description": "Characterizing the stimulation mode of a fracture is critical to assess the hydraulic efficiency and the seismic risk related to deep fluid manipulations. We have monitored the three-dimensional displacements of a fluid-driven fracture during water injections in a borehole at ~1.5 km depth in the crystalline rock of the Sanford Underground Research Facility (USA). The fracture initiates at 61% of the minimum horizontal stress by micro-shearing of the borehole on a foliation plane. As the fluid pressure increases further, borehole axial and radial displacements increase with injection time highlighting the opening and sliding of a new hydrofracture growing ~10 m away from the borehole, in accordance with the ambient normal stress regime and in alignment with the microseismicity. Our study reveals how fluid-driven fracture stimulation can be facilitated by a mixed-mode process controlled by the complex hydromechanical evolution of the growing fracture.
The data presented in this submission refer to the SIMFIP measurements and analyses of the stimulation tests conducted on the 164 ft (50 m) notch of the Sanford Underground Research Facility (SURF), during the EGS-Collab test 1. In addition to the datafiles, there is the draft of a manuscript submitted to Geophysical Research Letters (GRL)."
}
]
|
| DOI | 10.15121/1768008 |
| identifier | https://data.openei.org/submissions/7407 |
| issued | 2018-05-22T06:00:00Z |
| keyword |
[
"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"
]
|
| landingPage | https://gdr.openei.org/submissions/1289 |
| license | https://creativecommons.org/licenses/by/4.0/ |
| modified | 2023-10-25T17:29:22Z |
| programCode |
[
"019:006"
]
|
| projectLead | Lauren Boyd |
| projectNumber | EE0032708 |
| projectTitle | EGS Collab |
| publisher |
{
"name": "Lawrence Berkeley National Laboratory",
"@type": "org:Organization"
}
|
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| title | EGS Collab Experiment 1: In-situ observation of pre-, co- and post-seismic shear slip preceding hydraulic fracturing |
