Anna Kelbert, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 25
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 utilize rece
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 estimation of GI
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 main phase.
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 southern Brazil.
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 Cheyenne belt and
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 acquired at g
Authors
Jeffrey J. Love, Greg M. Lucas, E. Joshua Rigler, Benjamin Scott Murphy, Anna Kelbert, Paul A. Bedrosian
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 source(s) of i
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 convolving a s
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 relationship between
Authors
Benjamin Scott Murphy, Greg M. Lucas, Jeffrey J. Love, Anna Kelbert, Paul A. Bedrosian, E. Joshua Rigler
Simultaneous observations of geoelectric and geomagnetic fields produced by magnetospheric ULF waves
Geomagnetic perturbations (BGEO) related to magnetospheric ultralow frequency (ULF) waves induce electric fields within the conductive Earth—geoelectric fields (EGEO)—that in turn drive geomagnetically induced currents. Though numerous past studies have examined ULF wave BGEO from a space weather perspective, few studies have linked ULF waves with EGEO. Using recently available magnetotelluric imp
Authors
M. D. Hartinger, X. R. Shih, G. Lucas, Benjamin Scott Murphy, Anna Kelbert, J.B.H. Baker, E. Joshua Rigler, Paul A. Bedrosian
Geomagnetism Program research plan, 2020–2024
The Geomagnetism Program of the U.S. Geological Survey (USGS) monitors geomagnetic field variation through operation of a network of observatories across the United States and its territories, and it pursues scientific research needed to estimate and assess geomagnetic and geoelectric hazards. Over the next five years (2020–2024 inclusive) and in support of national and agency priorities, Geomagne
Authors
Jeffrey J. Love, Anna Kelbert, Benjamin S. Murphy, E. Joshua Rigler, Kristen A. Lewis
Modified GIC estimation using 3-D Earth conductivity
Geomagnetically induced currents (GICs) are quasi-direct current (DC) electric currents that flow in technological conductors during geomagnetic storms. Extreme GICs are hazardous to man-made infrastructure. GICs enter and exit the technological systems, such as the electric power grid, at grounding points, and their magnitudes depend on the currents that flow underground. They are, therefore, a f
Authors
Anna Kelbert, Greg M. Lucas
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, Congre
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, interoperabili
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 that can
Science and Products
Filter Total Items: 25
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 utilize rece
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 estimation of GI
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 main phase.
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 southern Brazil.
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 Cheyenne belt and
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 acquired at g
Authors
Jeffrey J. Love, Greg M. Lucas, E. Joshua Rigler, Benjamin Scott Murphy, Anna Kelbert, Paul A. Bedrosian
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 source(s) of i
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 convolving a s
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 relationship between
Authors
Benjamin Scott Murphy, Greg M. Lucas, Jeffrey J. Love, Anna Kelbert, Paul A. Bedrosian, E. Joshua Rigler
Simultaneous observations of geoelectric and geomagnetic fields produced by magnetospheric ULF waves
Geomagnetic perturbations (BGEO) related to magnetospheric ultralow frequency (ULF) waves induce electric fields within the conductive Earth—geoelectric fields (EGEO)—that in turn drive geomagnetically induced currents. Though numerous past studies have examined ULF wave BGEO from a space weather perspective, few studies have linked ULF waves with EGEO. Using recently available magnetotelluric imp
Authors
M. D. Hartinger, X. R. Shih, G. Lucas, Benjamin Scott Murphy, Anna Kelbert, J.B.H. Baker, E. Joshua Rigler, Paul A. Bedrosian
Geomagnetism Program research plan, 2020–2024
The Geomagnetism Program of the U.S. Geological Survey (USGS) monitors geomagnetic field variation through operation of a network of observatories across the United States and its territories, and it pursues scientific research needed to estimate and assess geomagnetic and geoelectric hazards. Over the next five years (2020–2024 inclusive) and in support of national and agency priorities, Geomagne
Authors
Jeffrey J. Love, Anna Kelbert, Benjamin S. Murphy, E. Joshua Rigler, Kristen A. Lewis
Modified GIC estimation using 3-D Earth conductivity
Geomagnetically induced currents (GICs) are quasi-direct current (DC) electric currents that flow in technological conductors during geomagnetic storms. Extreme GICs are hazardous to man-made infrastructure. GICs enter and exit the technological systems, such as the electric power grid, at grounding points, and their magnitudes depend on the currents that flow underground. They are, therefore, a f
Authors
Anna Kelbert, Greg M. Lucas
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, Congre
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, interoperabili
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 that can