Monitoring the Effect of Injection of Fluids from the Lake County Pipeline on Seismicity at The Geysers, California, Geothermal Field

Dellinger, M.; Majer, Ernest L.; Freeman, Katie T.; Johnson, Lane R.; Jarpe, S.; Nihei, Kurt T.; Hartline, Craig; Walters, Mark D.

doi:10.2172/1410331

Cited by 3 publications

(5 citation statements)

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“…Based on automatic processing of the short‐period network, two different earthquake catalogs are available through the North California Earthquake Data Center. We utilized the local EGS catalog and corresponding phase picks between June 2012 and July 2013 produced by the Lawrence Berkeley National Laboratory, which represents the most detailed local catalog for the geothermal field (Denllinger et al, ). During this time period a total of 120 earthquakes with M L > 3 were observed.…”

Section: Datamentioning

confidence: 99%

Analysis of Microseismicity Framing M_L > 2.5 Earthquakes at The Geysers Geothermal Field, California

et al. 2019

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Preparatory mechanisms accompanying or leading to nucleation of larger earthquakes have been observed at both laboratory and field scales, but conditions favoring the occurrence of observable preparatory processes are still largely unknown. In particular, it remains a matter of debate why some earthquakes occur spontaneously without noticeable precursors as opposed to events that are preceded by an extended failure process. In this study, we have generated new high‐resolution seismicity catalogs framing the occurrence of 20 ML > 2.5 earthquakes at The Geysers geothermal field in California. To this end, a seismicity catalog of the 11 days framing each large event was created. We selected 20 sequences sampling different hypocentral depths and hydraulic conditions within the field. Seismic activity and magnitude frequency distributions displayed by the different earthquake sequences are correlated with their location within the reservoir. Sequences located in the northwestern part of the reservoir show overall increased seismic activity and low b values, while the southeastern part is dominated by decreased seismic activity and higher b values. Periods of high injection coincide with high b values and vice versa. These observations potentially reflect varying differential and mean stresses and damage of the reservoir rocks across the field. About 50% of analyzed sequences exhibit no change in seismicity rate in response to the large main event. However, we find complex waveforms at the onset of the main earthquake, suggesting that small ruptures spontaneously grow into or trigger larger events.

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Section: Datamentioning

confidence: 99%

Analysis of Microseismicity Framing M_L > 2.5 Earthquakes at The Geysers Geothermal Field, California

et al. 2019

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“…Consequently, the local seismicity rate was significantly enhanced Dellinger et al, 2017;Majer & Peterson, 2007). In recent decades, a large volume of fluid was injected into the reservoir to maintain the pressure and steam production.…”

Section: 1029/2019gl082634mentioning

confidence: 99%

“…In recent decades, a large volume of fluid was injected into the reservoir to maintain the pressure and steam production. Consequently, the local seismicity rate was significantly enhanced (Beall et al, ; Dellinger et al, ; Majer & Peterson, ). Focal mechanisms and MTs of different subsets of events in this area were calculated using different waveform data and inversion schemes (Boyd et al, , ; Guilhem et al, ; L. R. Johnson, ; Kwiatek et al, ; Martínez‐Garzón et al, , ).…”

Section: Introductionmentioning

confidence: 99%

Frequency‐Dependent Moment Tensors of Induced Microearthquakes

Vavryčuk

Adamová

et al. 2019

Geophysical Research Letters

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Analysis of 984 induced microearthquakes from The Geysers geothermal reservoir in California reveals that the retrieved moment tensors depend on the frequency band of the inverted waveforms. The observed dependence is more significant for the percentages of the double‐couple, compensated linear vector dipole, and isotropic (ISO) components than for the focal mechanisms. The average root‐mean‐square of the moment tensors obtained in different frequency bands is correlated with spectra of ambient noise. The percentages of double‐couple and ISO components tend to decrease and increase with the upper cutoff frequency (fu), respectively. This suggests that shear rupture radiates energy preferentially in a lower frequency band and tensile rupture in a higher frequency band. Events displaying a strong increase of the ISO with fu are confined within the same depth interval as the injection points. This might be related to the strong thermoelastic effects in the vicinity of injection points that promote opening of small cracks adjacent to the main fractures.

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“…Such configuration simplifies the basic processing (e.g., detecting, picking, and locating events) of the broadband data set by using the existing catalogs derived from the short‐period data set. Three different earthquake catalogs based on the short‐period data set in The Geysers are hosted by the NCEDC, including the NCSN catalog produced by the NCEDC, the relocated NCSN catalog (DD‐NCSN) using the double‐differences method (Waldhauser, ; Waldhauser & Schaff, ), and the EGS catalog produced by the Lawrence Berkeley National Laboratory (Dellinger et al, ). The three catalogs display systematic shifts in depth of events (~1 km).…”

Section: Study Area and Datamentioning

confidence: 99%

“…Although the early studies of source mechanisms in The Geysers were limited by network geometry at that time as well as instruments and analyzing techniques, the regional stress dominating over the local stress perturbations and the existence of significant non‐double‐couple (non‐DC) mechanisms were observed already then (Julian et al, ; O'Connell & Johnson, ; Oppenheimer, ; Ross et al, , ). A permanent network of ~30 short‐period stations (4.5 Hz), operated by the Lawrence Berkeley National Laboratory since 2003, significantly increased the ability of detecting induced events in The Geysers (Dellinger et al, ; Majer & Peterson, ). Waveform data and microearthquake catalogs of high quality are archived in the Northern California Earthquake Data Center (NCEDC) and remarkably promote the studies of induced seismicity in The Geysers.…”

Section: Introductionmentioning

confidence: 99%

Moment Tensors of Induced Microearthquakes in The Geysers Geothermal Reservoir From Broadband Seismic Recordings: Implications for Faulting Regime, Stress Tensor, and Fluid Pressure

Vavryčuk

Adamová

et al. 2018

JGR Solid Earth

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Full moment tensors of 1,421 microearthquakes in The Geysers geothermal field were calculated using waveform data from a field‐wide broadband network and the approach based on the principal component analysis. Spatial characteristics of faulting regime, stress tensor and the isotropic component (ISO) of moment tensors were investigated. The studied events form different clusters dominated by normal faults (NF) and strike‐slip (SS) faults, respectively. The SS‐dominated clusters are related to the SS stress state observed in the southwestern side of the field where two NW‐SE trending fault zones exist. Increasing proportions of SS faults were observed near the shallow and deep parts of the NF‐dominated clusters. Temperature differences between the upper and lower parts of the reservoir do not change the overall stress states of clusters. The stress ratios in the NW part are much smaller than in the SE part of the field. The retrieved ISOs range between −5% and 25% for 96% of events. The average percentages of positive ISOs are correlated with the average injection rates in different clusters, and keep an increasing trend with depth below the main injection interval. Only 10% of events show negative ISO and are mainly constrained within the depth range of steam extraction. The proportion of events with negative ISO suggests much weaker seismic responses of the steam extraction than the water injection. The spatial variations of the ISO percentage do not follow the seismicity variations as the ISO is more sensitive to the pressure changes related to the fluid injection and migration.

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Monitoring the Effect of Injection of Fluids from the Lake County Pipeline on Seismicity at The Geysers, California, Geothermal Field

Cited by 3 publications

References 0 publications

Analysis of Microseismicity Framing M_L > 2.5 Earthquakes at The Geysers Geothermal Field, California

Analysis of Microseismicity Framing M_L > 2.5 Earthquakes at The Geysers Geothermal Field, California

Frequency‐Dependent Moment Tensors of Induced Microearthquakes

Moment Tensors of Induced Microearthquakes in The Geysers Geothermal Reservoir From Broadband Seismic Recordings: Implications for Faulting Regime, Stress Tensor, and Fluid Pressure

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Monitoring the Effect of Injection of Fluids from the Lake County Pipeline on Seismicity at The Geysers, California, Geothermal Field

Cited by 3 publications

References 0 publications

Analysis of Microseismicity Framing ML > 2.5 Earthquakes at The Geysers Geothermal Field, California

Analysis of Microseismicity Framing ML > 2.5 Earthquakes at The Geysers Geothermal Field, California

Frequency‐Dependent Moment Tensors of Induced Microearthquakes

Moment Tensors of Induced Microearthquakes in The Geysers Geothermal Reservoir From Broadband Seismic Recordings: Implications for Faulting Regime, Stress Tensor, and Fluid Pressure

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Analysis of Microseismicity Framing M_L > 2.5 Earthquakes at The Geysers Geothermal Field, California

Analysis of Microseismicity Framing M_L > 2.5 Earthquakes at The Geysers Geothermal Field, California