Michael Albert Mitchell, Ph.D. (Former Employee)
Science and Products
Annual repeat magnetotelluric data for monitoring The Geysers Geothermal Field, California (2021-2023) Annual repeat magnetotelluric data for monitoring The Geysers Geothermal Field, California (2021-2023)
The Geysers geothermal field in northern California is currently the largest energy producing steam field in the world. To better understand temporal subsurface changes in the steam field a geophysical monitoring project including continuous passive seimsic and repeat magnetotelluric measurements was funded by the California Energy Commission and led by Lawrence Berkeley National Lab. As...
Magnetotelluric data from the Clear Lake Region, Northern California Magnetotelluric data from the Clear Lake Region, Northern California
The Clear Lake Volcanic Field (CLVF) in northern California is a young (2 Ma-0.008 Ma) volcanic system that could be hazardous upon eruption. Magnetotellurics (MT) is a passive electromagnetic geophysical method that measures subsurface electrical resistivity by recording the Earth's electrical response to natural time varying magnetic fields. To further understand the magmatic system of...
Summary of results from monitoring the Geysers with continuous passive seismic and repeat magnetotelluric measurements (2021-2023) Summary of results from monitoring the Geysers with continuous passive seismic and repeat magnetotelluric measurements (2021-2023)
Understanding temporal variations in a geothermal field can support operators in decision making that pertains to optimizing production and mitigating hazards. Between 2021 and 2023, The Geysers geothermal field in northern California was monitored with an array of continuous passive seismic sensors and annual repeat magnetotelluric (MT) measurements. Each of these data sets were...
Authors
Jared R. Peacock, David Alumbaugh, Roland Gritto, Evan Um, Craig Ulrich, Michael A. Mitchell, Craig Hartline
Using DC resistivity ring array surveys to resolve conductive structures around tunnels or mine-workings Using DC resistivity ring array surveys to resolve conductive structures around tunnels or mine-workings
In underground environments, conventional direct current (DC) resistivity surveys with a single linear array of electrodes produce fundamentally non-unique inversions. These non-uniqueness and model resolution issues stem from limitations placed on the location of transmitters (TXs) and receivers (RXs) by the geometry of existing tunnels and boreholes. Poor excitation and/or sampling of...
Authors
Michael Mitchell, Douglas Oldenburg
Magnetotelluric monitoring of the Geysers Steam Field, northern California: Phase 2 Magnetotelluric monitoring of the Geysers Steam Field, northern California: Phase 2
An original magnetotelluric (MT) survey collected in 2017 included 42 MT stations mainly in the northwestern part of The Geysers geothermal field in northern California. These data were modeled in 3D and imaged the electrically conductive cover, the electrically resistive steam field, and the electrically resistive Geysers plutonic complex (Peacock et al., 2020; Peacock et al. 2020a)...
Authors
Jared R. Peacock, David Alumbaugh, Michael Albert Mitchell, Craig Hartline
Imaging the magmatic plumbing of the Clear Lake Volcanic Field using 3-D gravity inversions Imaging the magmatic plumbing of the Clear Lake Volcanic Field using 3-D gravity inversions
The Quaternary Clear Lake Volcanic Field (CLVF) in the Northern California Coast Range is the youngest of a string of northward-younging volcanic centers in the state. The CLVF is located within the broad San Andreas Transform Fault System and has been active intermittently for ∼2 million years. Heat beneath the CLVF supports The Geysers, one of the largest producing geothermal fields in...
Authors
Michael Mitchell, Jared R. Peacock, Seth Burgess
Repeat magnetotelluric measurements to monitor The Geysers steam field in northern California Repeat magnetotelluric measurements to monitor The Geysers steam field in northern California
The Geysers in northern California is the world’s largest electricity generating steam field. To help understand changes in the steam reservoir, repeat magnetotelluric (MT) measurements are being collected once a year from 2021-2023. These data will be compared and modeled to provide 4-D images of changes within the reservoir. Joint inversion with passive seismic data will be done to...
Authors
Jared R. Peacock, David Alumbaugh, Michael Mitchell, Craig Hartline
Science and Products
Annual repeat magnetotelluric data for monitoring The Geysers Geothermal Field, California (2021-2023) Annual repeat magnetotelluric data for monitoring The Geysers Geothermal Field, California (2021-2023)
The Geysers geothermal field in northern California is currently the largest energy producing steam field in the world. To better understand temporal subsurface changes in the steam field a geophysical monitoring project including continuous passive seimsic and repeat magnetotelluric measurements was funded by the California Energy Commission and led by Lawrence Berkeley National Lab. As...
Magnetotelluric data from the Clear Lake Region, Northern California Magnetotelluric data from the Clear Lake Region, Northern California
The Clear Lake Volcanic Field (CLVF) in northern California is a young (2 Ma-0.008 Ma) volcanic system that could be hazardous upon eruption. Magnetotellurics (MT) is a passive electromagnetic geophysical method that measures subsurface electrical resistivity by recording the Earth's electrical response to natural time varying magnetic fields. To further understand the magmatic system of...
Summary of results from monitoring the Geysers with continuous passive seismic and repeat magnetotelluric measurements (2021-2023) Summary of results from monitoring the Geysers with continuous passive seismic and repeat magnetotelluric measurements (2021-2023)
Understanding temporal variations in a geothermal field can support operators in decision making that pertains to optimizing production and mitigating hazards. Between 2021 and 2023, The Geysers geothermal field in northern California was monitored with an array of continuous passive seismic sensors and annual repeat magnetotelluric (MT) measurements. Each of these data sets were...
Authors
Jared R. Peacock, David Alumbaugh, Roland Gritto, Evan Um, Craig Ulrich, Michael A. Mitchell, Craig Hartline
Using DC resistivity ring array surveys to resolve conductive structures around tunnels or mine-workings Using DC resistivity ring array surveys to resolve conductive structures around tunnels or mine-workings
In underground environments, conventional direct current (DC) resistivity surveys with a single linear array of electrodes produce fundamentally non-unique inversions. These non-uniqueness and model resolution issues stem from limitations placed on the location of transmitters (TXs) and receivers (RXs) by the geometry of existing tunnels and boreholes. Poor excitation and/or sampling of...
Authors
Michael Mitchell, Douglas Oldenburg
Magnetotelluric monitoring of the Geysers Steam Field, northern California: Phase 2 Magnetotelluric monitoring of the Geysers Steam Field, northern California: Phase 2
An original magnetotelluric (MT) survey collected in 2017 included 42 MT stations mainly in the northwestern part of The Geysers geothermal field in northern California. These data were modeled in 3D and imaged the electrically conductive cover, the electrically resistive steam field, and the electrically resistive Geysers plutonic complex (Peacock et al., 2020; Peacock et al. 2020a)...
Authors
Jared R. Peacock, David Alumbaugh, Michael Albert Mitchell, Craig Hartline
Imaging the magmatic plumbing of the Clear Lake Volcanic Field using 3-D gravity inversions Imaging the magmatic plumbing of the Clear Lake Volcanic Field using 3-D gravity inversions
The Quaternary Clear Lake Volcanic Field (CLVF) in the Northern California Coast Range is the youngest of a string of northward-younging volcanic centers in the state. The CLVF is located within the broad San Andreas Transform Fault System and has been active intermittently for ∼2 million years. Heat beneath the CLVF supports The Geysers, one of the largest producing geothermal fields in...
Authors
Michael Mitchell, Jared R. Peacock, Seth Burgess
Repeat magnetotelluric measurements to monitor The Geysers steam field in northern California Repeat magnetotelluric measurements to monitor The Geysers steam field in northern California
The Geysers in northern California is the world’s largest electricity generating steam field. To help understand changes in the steam reservoir, repeat magnetotelluric (MT) measurements are being collected once a year from 2021-2023. These data will be compared and modeled to provide 4-D images of changes within the reservoir. Joint inversion with passive seismic data will be done to...
Authors
Jared R. Peacock, David Alumbaugh, Michael Mitchell, Craig Hartline