Anna Kelbert, Ph.D. (Former Employee)
Science and Products
Development of a Flexible Multi-Channel Spatiotemporal Geophysical HDF5 Data Format Supporting FAIR
A unique opportunity for USGS to collaborate with IRIS-PASSCAL (the national seismic instrument facility) has presented itself to develop a geophysical data archive format that follows FAIR principles. IRIS-PASSCAL is extending facility to include magnetotelluric (MT) instruments prescribing the need for them to archive collected MT data by extending their existing protocol. Concurrently...
Metadata standards for Magnetotelluric Time Series Data
Magnetotellurics (MT) is an electromagnetic geophysical method that is sensitive to variations in subsurface electrical resistivity. Measurements of natural electric and magnetic fields are done in the time domain, where instruments can record for a couple of hours up to mulitple months resulting in data sets on the order of gigabytes. The principles of findability, accessibility...
Filter Total Items: 28
The solar cycle, geology, and geoelectric hazards for power grids
When sunspots are large and numerous, intense magnetic storms are likely to occur on the Earth. Magnetic storms can generate electric fields in the Earth, and these fields can, in turn, interfere with electric power transmission grids that are grounded at the Earth’s surface. Across the contiguous United States, geoelectric hazards are highest in the Upper Midwest and in the East. These...
Authors
Jeffrey J. Love, Steven Sobieszczyk, E. Joshua Rigler, Anna Kelbert, Kristen A. Lewis
Aurora: An open-source Python implementation of the EMTF package for magnetotelluric data processing using MTH5 and mt-metadata
The Aurora software package robustly estimates single station and remote reference electromagnetic transfer functions (TFs) from magnetotelluric (MT) time series. Aurora is part of an open-source processing workflow that leverages the self-describing data container MTH5, which in turn leverages the general mt-metadata framework to manage metadata. These pre-existing packages simplify the...
Authors
Karl Kappler, Jared R. Peacock, Gary D. Egbert, Andrew Frassetto, Lindsey Heagy, Anna Kelbert, Laura Keyson, Douglas W. Oldenburg, Timothy Ronan, Justin Sweet
Hybrid CPU-GPU solution to regularized divergence-free curl-curl equations for electromagnetic inversion problems
The Curl-Curl equation is the foundation of time-harmonic electromagnetic (EM) problems in geophysics. The efficiency of its solution is key to EM simulations, accounting for over 95% of the computation cost in geophysical inversions for magnetotelluric or controlled-source EM problems. However, most published EM inversion codes are still central processing unit (CPU)-based and cannot...
Authors
Hao Dong, Kai Sun, Gary D. Egbert, Anna Kelbert, Naser Meqbel
Geoelectric field model validation in the southern California Edison system: Case study
Geomagnetic storms are a natural phenomenon that cause magnetic field variations at the surface of the Earth. These variations induce electrical current in natural and artificial conductors at and below the surface, resulting in geomagnetically induced currents (GIC) in power systems. The key to modeling GIC is to estimate the geoelectric field in the region of the power grid. The...
Authors
Christopher C. Balch, Chaoyang Jing, Anna Kelbert, Patricia Arons, Kevin Richardson
The March 1940 superstorm: Geoelectromagnetic hazards and impacts on American communication and power systems
An analysis is made of geophysical records of the 24 March 1940, magnetic storm and related reports of interference on long-line communication and power systems across the contiguous United States and, to a lesser extent, Canada. Most long-line system interference occurred during local daytime, after the second of two storm sudden commencements and during the early part of the storm's...
Authors
Jeffrey J. Love, E. Joshua Rigler, Michael D Hartinger, Greg M. Lucas, Anna Kelbert, Paul A. Bedrosian
Estimating geomagnetically induced currents in southern Brazil using 3-D Earth resistivity model
Geomagnetically induced currents (GICs) result from the interaction of the time variation of ground magnetic field during a geomagnetic disturbance with the Earth's deep electrical resistivity structure. In this study, we simulate induced GICs in a hypothetical representation of a low-latitude power transmission network located mainly over the large Paleozoic Paraná basin (PB) in...
Authors
Karen V. Espinosa Sarmiento, Antonio L. Padilha, Livia R. Alves, Adam Schultz, Anna Kelbert
Geoelectric constraints on the Precambrian assembly and architecture of southern Laurentia
Using images from an updated and expanded three-dimensional electrical conductivity synthesis model for the contiguous United States (CONUS), we highlight the key continent-scale geoelectric structures that are associated with the Precambrian assembly of southern Laurentia. Conductivity anomalies are associated with the Trans-Hudson orogen, the Penokean suture, the ca. 1.8–1.7 Ga...
Authors
Benjamin Scott Murphy, Paul A. Bedrosian, Anna Kelbert
Mapping a magnetic superstorm: March 1989 geoelectric hazards and impacts on United States power systems
A study is made of the relationships between geomagnetic and geoelectric field variation, Earth-surface impedance, and operational interference (anomalies) experienced on electric-power systems across the contiguous United States during the March 13-14, 1989 magnetic storm. For this, a 1-minute-resolution sequence of geomagnetic field maps is constructed from magnetometer time series...
Authors
Jeffrey J. Love, Greg M. Lucas, E. Joshua Rigler, Benjamin Scott Murphy, Anna Kelbert, Paul A. Bedrosian
MTH5: An archive and exchangeable data format for magnetotelluric time series data
Magnetotellurics (MT) is a passive electromagnetic geophysical method that measures variations in subsurface electrical resistivity. MT data are collected in the time domain and processed in the frequency domain to produce estimates of a transfer function representing the Earth’s electrical structure. Unfortunately, the MT community lacks metadata and data standards for time series data...
Authors
Jared R. Peacock, Karl Kappler, Lindsey Heagy, Timothy Ronan, Anna Kelbert, Andrew Frassetto
Characteristics and sources of intense geoelectric fields in the United States: Comparative analysis of multiple geomagnetic storms
Intense geoelectric fields during geomagnetic storms drive geomagnetically induced currents in power grids and other infrastructure, yet there are limited direct measurements of these storm-time geoelectric fields. Moreover, most previous studies examining storm-time geoelectric fields focused on single events or small geographic regions, making it difficult to determine the typical...
Authors
Xueling Shi, Michael D Hartinger, Joseph B. H. Baker, Benjamin Scott Murphy, Paul A. Bedrosian, Anna Kelbert, Erin (Josh) Rigler
Down to Earth with nuclear electromagnetic pulse: Realistic surface impedance affects mapping of the E3 geoelectric hazard
An analysis is made of Earth-surface geoelectric fields and voltages on electricity transmission power-grids induced by a late-phase E3 nuclear electromagnetic pulse (EMP). A hypothetical scenario is considered of an explosion of several hundred kilotons set several hundred kilometers above the eastern-midcontinental United States. Ground-level E3 geoelectric fields are estimated by...
Authors
Jeffrey J. Love, Greg M. Lucas, Benjamin Scott Murphy, Paul A. Bedrosian, E. Joshua Rigler, Anna Kelbert
Magnetotelluric sampling and geoelectric hazard estimation: Are national-scale surveys sufficient?
At present, the most reliable information for inferring storm-time ground electric fields along electrical transmission lines comes from coarsely sampled, national-scale magnetotelluric (MT) data sets, such as that provided by the EarthScope USArray program. An underlying assumption in the use of such data is that they adequately sample the spatial heterogeneity of the surface...
Authors
Benjamin Scott Murphy, Greg M. Lucas, Jeffrey J. Love, Anna Kelbert, Paul A. Bedrosian, E. Joshua Rigler
MT-metadata: Open-source Python package to work with magnetotelluric metadata
An open-source Python package to make reading/writing/editing magnetotelluric metadata easier.
Electromagnetic Transfer Function File Conversion Utilities (EMTF FCU)
Magnetotelluric impedances and other similar transfer functions are important for geophysical interpretation and for space weather hazards. I helped develop and continue to curate a database known as IRIS EMTF, http://ds.iris.edu/spud/emtf which uses something called EMTF XML format for storing the data. EMTF FCU v4.1 software consists of a set of freely available format conversion tools...
Science and Products
Development of a Flexible Multi-Channel Spatiotemporal Geophysical HDF5 Data Format Supporting FAIR
A unique opportunity for USGS to collaborate with IRIS-PASSCAL (the national seismic instrument facility) has presented itself to develop a geophysical data archive format that follows FAIR principles. IRIS-PASSCAL is extending facility to include magnetotelluric (MT) instruments prescribing the need for them to archive collected MT data by extending their existing protocol. Concurrently...
Metadata standards for Magnetotelluric Time Series Data
Magnetotellurics (MT) is an electromagnetic geophysical method that is sensitive to variations in subsurface electrical resistivity. Measurements of natural electric and magnetic fields are done in the time domain, where instruments can record for a couple of hours up to mulitple months resulting in data sets on the order of gigabytes. The principles of findability, accessibility...
Filter Total Items: 28
The solar cycle, geology, and geoelectric hazards for power grids
When sunspots are large and numerous, intense magnetic storms are likely to occur on the Earth. Magnetic storms can generate electric fields in the Earth, and these fields can, in turn, interfere with electric power transmission grids that are grounded at the Earth’s surface. Across the contiguous United States, geoelectric hazards are highest in the Upper Midwest and in the East. These...
Authors
Jeffrey J. Love, Steven Sobieszczyk, E. Joshua Rigler, Anna Kelbert, Kristen A. Lewis
Aurora: An open-source Python implementation of the EMTF package for magnetotelluric data processing using MTH5 and mt-metadata
The Aurora software package robustly estimates single station and remote reference electromagnetic transfer functions (TFs) from magnetotelluric (MT) time series. Aurora is part of an open-source processing workflow that leverages the self-describing data container MTH5, which in turn leverages the general mt-metadata framework to manage metadata. These pre-existing packages simplify the...
Authors
Karl Kappler, Jared R. Peacock, Gary D. Egbert, Andrew Frassetto, Lindsey Heagy, Anna Kelbert, Laura Keyson, Douglas W. Oldenburg, Timothy Ronan, Justin Sweet
Hybrid CPU-GPU solution to regularized divergence-free curl-curl equations for electromagnetic inversion problems
The Curl-Curl equation is the foundation of time-harmonic electromagnetic (EM) problems in geophysics. The efficiency of its solution is key to EM simulations, accounting for over 95% of the computation cost in geophysical inversions for magnetotelluric or controlled-source EM problems. However, most published EM inversion codes are still central processing unit (CPU)-based and cannot...
Authors
Hao Dong, Kai Sun, Gary D. Egbert, Anna Kelbert, Naser Meqbel
Geoelectric field model validation in the southern California Edison system: Case study
Geomagnetic storms are a natural phenomenon that cause magnetic field variations at the surface of the Earth. These variations induce electrical current in natural and artificial conductors at and below the surface, resulting in geomagnetically induced currents (GIC) in power systems. The key to modeling GIC is to estimate the geoelectric field in the region of the power grid. The...
Authors
Christopher C. Balch, Chaoyang Jing, Anna Kelbert, Patricia Arons, Kevin Richardson
The March 1940 superstorm: Geoelectromagnetic hazards and impacts on American communication and power systems
An analysis is made of geophysical records of the 24 March 1940, magnetic storm and related reports of interference on long-line communication and power systems across the contiguous United States and, to a lesser extent, Canada. Most long-line system interference occurred during local daytime, after the second of two storm sudden commencements and during the early part of the storm's...
Authors
Jeffrey J. Love, E. Joshua Rigler, Michael D Hartinger, Greg M. Lucas, Anna Kelbert, Paul A. Bedrosian
Estimating geomagnetically induced currents in southern Brazil using 3-D Earth resistivity model
Geomagnetically induced currents (GICs) result from the interaction of the time variation of ground magnetic field during a geomagnetic disturbance with the Earth's deep electrical resistivity structure. In this study, we simulate induced GICs in a hypothetical representation of a low-latitude power transmission network located mainly over the large Paleozoic Paraná basin (PB) in...
Authors
Karen V. Espinosa Sarmiento, Antonio L. Padilha, Livia R. Alves, Adam Schultz, Anna Kelbert
Geoelectric constraints on the Precambrian assembly and architecture of southern Laurentia
Using images from an updated and expanded three-dimensional electrical conductivity synthesis model for the contiguous United States (CONUS), we highlight the key continent-scale geoelectric structures that are associated with the Precambrian assembly of southern Laurentia. Conductivity anomalies are associated with the Trans-Hudson orogen, the Penokean suture, the ca. 1.8–1.7 Ga...
Authors
Benjamin Scott Murphy, Paul A. Bedrosian, Anna Kelbert
Mapping a magnetic superstorm: March 1989 geoelectric hazards and impacts on United States power systems
A study is made of the relationships between geomagnetic and geoelectric field variation, Earth-surface impedance, and operational interference (anomalies) experienced on electric-power systems across the contiguous United States during the March 13-14, 1989 magnetic storm. For this, a 1-minute-resolution sequence of geomagnetic field maps is constructed from magnetometer time series...
Authors
Jeffrey J. Love, Greg M. Lucas, E. Joshua Rigler, Benjamin Scott Murphy, Anna Kelbert, Paul A. Bedrosian
MTH5: An archive and exchangeable data format for magnetotelluric time series data
Magnetotellurics (MT) is a passive electromagnetic geophysical method that measures variations in subsurface electrical resistivity. MT data are collected in the time domain and processed in the frequency domain to produce estimates of a transfer function representing the Earth’s electrical structure. Unfortunately, the MT community lacks metadata and data standards for time series data...
Authors
Jared R. Peacock, Karl Kappler, Lindsey Heagy, Timothy Ronan, Anna Kelbert, Andrew Frassetto
Characteristics and sources of intense geoelectric fields in the United States: Comparative analysis of multiple geomagnetic storms
Intense geoelectric fields during geomagnetic storms drive geomagnetically induced currents in power grids and other infrastructure, yet there are limited direct measurements of these storm-time geoelectric fields. Moreover, most previous studies examining storm-time geoelectric fields focused on single events or small geographic regions, making it difficult to determine the typical...
Authors
Xueling Shi, Michael D Hartinger, Joseph B. H. Baker, Benjamin Scott Murphy, Paul A. Bedrosian, Anna Kelbert, Erin (Josh) Rigler
Down to Earth with nuclear electromagnetic pulse: Realistic surface impedance affects mapping of the E3 geoelectric hazard
An analysis is made of Earth-surface geoelectric fields and voltages on electricity transmission power-grids induced by a late-phase E3 nuclear electromagnetic pulse (EMP). A hypothetical scenario is considered of an explosion of several hundred kilotons set several hundred kilometers above the eastern-midcontinental United States. Ground-level E3 geoelectric fields are estimated by...
Authors
Jeffrey J. Love, Greg M. Lucas, Benjamin Scott Murphy, Paul A. Bedrosian, E. Joshua Rigler, Anna Kelbert
Magnetotelluric sampling and geoelectric hazard estimation: Are national-scale surveys sufficient?
At present, the most reliable information for inferring storm-time ground electric fields along electrical transmission lines comes from coarsely sampled, national-scale magnetotelluric (MT) data sets, such as that provided by the EarthScope USArray program. An underlying assumption in the use of such data is that they adequately sample the spatial heterogeneity of the surface...
Authors
Benjamin Scott Murphy, Greg M. Lucas, Jeffrey J. Love, Anna Kelbert, Paul A. Bedrosian, E. Joshua Rigler
MT-metadata: Open-source Python package to work with magnetotelluric metadata
An open-source Python package to make reading/writing/editing magnetotelluric metadata easier.
Electromagnetic Transfer Function File Conversion Utilities (EMTF FCU)
Magnetotelluric impedances and other similar transfer functions are important for geophysical interpretation and for space weather hazards. I helped develop and continue to curate a database known as IRIS EMTF, http://ds.iris.edu/spud/emtf which uses something called EMTF XML format for storing the data. EMTF FCU v4.1 software consists of a set of freely available format conversion tools...