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2021 |
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| 56. | Micallef, Aaron; Person, Mark; Berndt, Christian; Bertoni, Claudia; Cohen, Denis; Dugan, Brandon; Evans, Rob; Haroon, Amir; Hensen, Christian; Jegen, Marion; Key, Kerry; Kooi, Henk; Liebetrau, Volker; Lofi, Johanna; Mailloux, Brian J; Martin‐Nagle, Renée; Michael, Holly A; Müller, Thomas; Schmidt, Mark; Schwalenberg, Katrin; Trembath‐Reichert, Elizabeth; Weymer, Bradley; Zhang, Yipeng; Thomas, Ariel T Offshore Freshened Groundwater in Continental Margins Journal Article Reviews of Geophysics, 59 (1), 2021, ISSN: 8755-1209. @article{sgur, title = {Offshore Freshened Groundwater in Continental Margins}, author = {Aaron Micallef and Mark Person and Christian Berndt and Claudia Bertoni and Denis Cohen and Brandon Dugan and Rob Evans and Amir Haroon and Christian Hensen and Marion Jegen and Kerry Key and Henk Kooi and Volker Liebetrau and Johanna Lofi and Brian J Mailloux and Renée Martin‐Nagle and Holly A Michael and Thomas Müller and Mark Schmidt and Katrin Schwalenberg and Elizabeth Trembath‐Reichert and Bradley Weymer and Yipeng Zhang and Ariel T Thomas}, doi = {10.1029/2020rg000706}, issn = {8755-1209}, year = {2021}, date = {2021-01-01}, journal = {Reviews of Geophysics}, volume = {59}, number = {1}, abstract = {First reported in the 1960s, offshore freshened groundwater (OFG) has now been documented in most continental margins around the world. In this review we compile a database documenting OFG occurrences and analyze it to establish the general characteristics and controlling factors. We also assess methods used to map and characterize OFG, identify major knowledge gaps, and propose strategies to address them. OFG has a global volume of 1 × 106 km3; it predominantly occurs within 55 km of the coast and down to a water depth of 100 m. OFG is mainly hosted within siliciclastic aquifers on passive margins and recharged by meteoric water during Pleistocene sea level lowstands. Key factors influencing OFG distribution are topography‐driven flow, salinization via haline convection, permeability contrasts, and the continuity/connectivity of permeable and confining strata. Geochemical and stable isotope measurements of pore waters from boreholes have provided insights into OFG emplacement mechanisms, while recent advances in seismic reflection profiling, electromagnetic surveying, and numerical models have improved our understanding of OFG geometry and controls. Key knowledge gaps, such as the extent and function of OFG, and the timing of their emplacement, can be addressed by the application of isotopic age tracers, joint inversion of electromagnetic and seismic reflection data, and development of three‐dimensional hydrological models. We show that such advances, combined with site‐specific modeling, are necessary to assess the potential use of OFG as an unconventional source of water and its role in sub‐seafloor geomicrobiology. This review paper considers offshore freshened groundwater (OFG), which is water hosted in sediments and rocks below the seafloor, with a total dissolved solid concentration lower than seawater. We have compiled >300 records to demonstrate that freshened groundwater occurs offshore on most continents around the world and has a global volume of 1 × 106 km3. The majority of OFG was deposited when sea level was lower than today and is hosted in sandy sub‐seafloor layers that are located within 55 km of coasts in water depths less than 100 m. We present a range of geochemical, geophysical, and modeling approaches that have successfully been used to investigate OFG systems. We also propose approaches to address key scientific questions related to OFG, including whether it may be used as an unconventional source of potable water in coastal areas. Most known OFG is located at water depths of <100 m within 55 km of the coast, hosted in siliciclastic aquifers in passive margins Key gaps in knowledge include the extent and function of OFG systems, as well as the mechanism and timing of emplacement Isotopic tracers, jointly inverted geophysical data and 3‐D hydrological models can help address these knowledge gaps}, keywords = {}, pubstate = {published}, tppubtype = {article} } First reported in the 1960s, offshore freshened groundwater (OFG) has now been documented in most continental margins around the world. In this review we compile a database documenting OFG occurrences and analyze it to establish the general characteristics and controlling factors. We also assess methods used to map and characterize OFG, identify major knowledge gaps, and propose strategies to address them. OFG has a global volume of 1 × 106 km3; it predominantly occurs within 55 km of the coast and down to a water depth of 100 m. OFG is mainly hosted within siliciclastic aquifers on passive margins and recharged by meteoric water during Pleistocene sea level lowstands. Key factors influencing OFG distribution are topography‐driven flow, salinization via haline convection, permeability contrasts, and the continuity/connectivity of permeable and confining strata. Geochemical and stable isotope measurements of pore waters from boreholes have provided insights into OFG emplacement mechanisms, while recent advances in seismic reflection profiling, electromagnetic surveying, and numerical models have improved our understanding of OFG geometry and controls. Key knowledge gaps, such as the extent and function of OFG, and the timing of their emplacement, can be addressed by the application of isotopic age tracers, joint inversion of electromagnetic and seismic reflection data, and development of three‐dimensional hydrological models. We show that such advances, combined with site‐specific modeling, are necessary to assess the potential use of OFG as an unconventional source of water and its role in sub‐seafloor geomicrobiology. This review paper considers offshore freshened groundwater (OFG), which is water hosted in sediments and rocks below the seafloor, with a total dissolved solid concentration lower than seawater. We have compiled >300 records to demonstrate that freshened groundwater occurs offshore on most continents around the world and has a global volume of 1 × 106 km3. The majority of OFG was deposited when sea level was lower than today and is hosted in sandy sub‐seafloor layers that are located within 55 km of coasts in water depths less than 100 m. We present a range of geochemical, geophysical, and modeling approaches that have successfully been used to investigate OFG systems. We also propose approaches to address key scientific questions related to OFG, including whether it may be used as an unconventional source of potable water in coastal areas. Most known OFG is located at water depths of <100 m within 55 km of the coast, hosted in siliciclastic aquifers in passive margins Key gaps in knowledge include the extent and function of OFG systems, as well as the mechanism and timing of emplacement Isotopic tracers, jointly inverted geophysical data and 3‐D hydrological models can help address these knowledge gaps |
| 55. | Key, Kerry; Constable, Steven Inverted long-baseline acoustic navigation of deep-towed CSEM transmitters and receivers Journal Article Marine Geophysical Research, 42 (1), pp. 6, 2021, ISSN: 0025-3235. @article{Key.2021, title = {Inverted long-baseline acoustic navigation of deep-towed CSEM transmitters and receivers}, author = {Kerry Key and Steven Constable}, doi = {10.1007/s11001-021-09427-z}, issn = {0025-3235}, year = {2021}, date = {2021-01-01}, journal = {Marine Geophysical Research}, volume = {42}, number = {1}, pages = {6}, abstract = {We develop an inverted long-baseline (ILBL) acoustic navigation system for determining the position of deep-towed instruments, such as controlled-source electromagnetic transmitters and receivers. The ILBL system uses a deep-tow mounted acoustic transceiver system to measure travel times to a pair of surface transponders towed on paravanes behind the survey vessel. The travel times, transponder positions and pressure depth data are inverted for the lateral position of the deep-tow vehicle, as well as the positions of any relay transponders on the antenna and receiver array that are towed horizontal behind the deep-tow vehicle. Three example applications demonstrate position accuracies of about 5 and 37 m in the inline and crossline directions for 3 km water depths and around 6 m for 1 km depth. The portability and generality of the system make it suitable for deep-tow applications for geophysical, geochemical and geological surveying purposes. We have shown that the accuracy of the ILBL system is similar to that of commercial USBL systems, but is considerably more cost effective than even portable USBL systems, and can be used on vessels lacking permanently installed USBL transceiver heads. Further, it can be used in water depths of 5,000 m or more. It could also be readily modified for further improving its position accuracy if desired.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We develop an inverted long-baseline (ILBL) acoustic navigation system for determining the position of deep-towed instruments, such as controlled-source electromagnetic transmitters and receivers. The ILBL system uses a deep-tow mounted acoustic transceiver system to measure travel times to a pair of surface transponders towed on paravanes behind the survey vessel. The travel times, transponder positions and pressure depth data are inverted for the lateral position of the deep-tow vehicle, as well as the positions of any relay transponders on the antenna and receiver array that are towed horizontal behind the deep-tow vehicle. Three example applications demonstrate position accuracies of about 5 and 37 m in the inline and crossline directions for 3 km water depths and around 6 m for 1 km depth. The portability and generality of the system make it suitable for deep-tow applications for geophysical, geochemical and geological surveying purposes. We have shown that the accuracy of the ILBL system is similar to that of commercial USBL systems, but is considerably more cost effective than even portable USBL systems, and can be used on vessels lacking permanently installed USBL transceiver heads. Further, it can be used in water depths of 5,000 m or more. It could also be readily modified for further improving its position accuracy if desired. |
| 54. | Chesley, Christine; Naif, Samer; Key, Kerry; Bassett, Dan Fluid-rich subducting topography generates anomalous forearc porosity Journal Article Nature, 595 (7866), pp. 255–260, 2021, ISSN: 0028-0836. @article{Chesley.2021, title = {Fluid-rich subducting topography generates anomalous forearc porosity}, author = {Christine Chesley and Samer Naif and Kerry Key and Dan Bassett}, url = {https://www.nature.com/articles/s41586-021-03619-8.epdf?sharing_token=059dEpg3Ed0LSl8d02FaDdRgN0jAjWel9jnR3ZoTv0M_rJgybuzy9QY1Pp-7852_sl1dUqsZYNhDbIkAbAwN8O00dlhHX0kHWAqHdpqZsFD8QgiZoZHW8WJbEVUSVahCUzKCDjMjf_MTwwA70y77ZzabPEx99qB99b1SDa08GkI%3D}, doi = {10.1038/s41586-021-03619-8}, issn = {0028-0836}, year = {2021}, date = {2021-01-01}, journal = {Nature}, volume = {595}, number = {7866}, pages = {255--260}, abstract = {The role of subducting topography on the mode of fault slip—particularly whether it hinders or facilitates large megathrust earthquakes—remains a controversial topic in subduction dynamics1–5. Models have illustrated the potential for subducting topography to severely alter the structure, stress state and mechanics of subduction zones4,6; however, direct geophysical imaging of the complex fracture networks proposed and the hydrology of both the subducting topography and the associated upper plate damage zones remains elusive. Here we use passive and controlled-source seafloor electromagnetic data collected at the northern Hikurangi Margin, New Zealand, to constrain electrical resistivity in a region of active seamount subduction. We show that a seamount on the incoming plate contains a thin, low-porosity basaltic cap that traps a conductive matrix of porous volcaniclastics and altered material over a resistive core, which allows 3.2 to 4.7 times more water to subduct, compared with normal, unfaulted oceanic lithosphere. In the forearc, we image a sediment-starved plate interface above a subducting seamount with similar electrical structure to the incoming plate seamount. A sharp resistive peak within the subducting seamount lies directly beneath a prominent upper plate conductive anomaly. The coincidence of this upper plate anomaly with the location of burst-type repeating earthquakes and seismicity associated with a recent slow slip event7 directly links subducting topography to the creation of fluid-rich damage zones in the forearc that alter the effective normal stress at the plate interface by modulating the fluid overpressure. In addition to severely modifying the structure and physical conditions of the upper plate, subducting seamounts represent an underappreciated mechanism for transporting a considerable flux of water to the forearc and deeper mantle. Electromagnetic data collected at the northern Hikurangi Margin, New Zealand show that a seamount on the incoming plate allows more water to subduct, compared with normal, unfaulted oceanic lithosphere.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The role of subducting topography on the mode of fault slip—particularly whether it hinders or facilitates large megathrust earthquakes—remains a controversial topic in subduction dynamics1–5. Models have illustrated the potential for subducting topography to severely alter the structure, stress state and mechanics of subduction zones4,6; however, direct geophysical imaging of the complex fracture networks proposed and the hydrology of both the subducting topography and the associated upper plate damage zones remains elusive. Here we use passive and controlled-source seafloor electromagnetic data collected at the northern Hikurangi Margin, New Zealand, to constrain electrical resistivity in a region of active seamount subduction. We show that a seamount on the incoming plate contains a thin, low-porosity basaltic cap that traps a conductive matrix of porous volcaniclastics and altered material over a resistive core, which allows 3.2 to 4.7 times more water to subduct, compared with normal, unfaulted oceanic lithosphere. In the forearc, we image a sediment-starved plate interface above a subducting seamount with similar electrical structure to the incoming plate seamount. A sharp resistive peak within the subducting seamount lies directly beneath a prominent upper plate conductive anomaly. The coincidence of this upper plate anomaly with the location of burst-type repeating earthquakes and seismicity associated with a recent slow slip event7 directly links subducting topography to the creation of fluid-rich damage zones in the forearc that alter the effective normal stress at the plate interface by modulating the fluid overpressure. In addition to severely modifying the structure and physical conditions of the upper plate, subducting seamounts represent an underappreciated mechanism for transporting a considerable flux of water to the forearc and deeper mantle. Electromagnetic data collected at the northern Hikurangi Margin, New Zealand show that a seamount on the incoming plate allows more water to subduct, compared with normal, unfaulted oceanic lithosphere. |
2020 |
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| 53. | Miller, David; Bennington, Ninfa; Haney, Matthew; Bedrosian, Paul; Key, Kerry; Thurber, Clifford; Hart, Laney; Ohlendorf, Summer Linking Magma Storage and Ascent to Eruption Volume and Composition at an Arc Caldera Journal Article Geophysical Research Letters, 47 (14), pp. 257 – 9, 2020. @article{Miller.202066, title = {Linking Magma Storage and Ascent to Eruption Volume and Composition at an Arc Caldera}, author = {David Miller and Ninfa Bennington and Matthew Haney and Paul Bedrosian and Kerry Key and Clifford Thurber and Laney Hart and Summer Ohlendorf}, doi = {10.1029/2020gl088122}, year = {2020}, date = {2020-01-01}, journal = {Geophysical Research Letters}, volume = {47}, number = {14}, pages = {257 -- 9}, abstract = {Okmok caldera is underlain by radially anisotropic velocity structures indicating a central sill complex and a surrounding ring of dikes The path of magma through or around the central stacked sill...}, keywords = {}, pubstate = {published}, tppubtype = {article} } Okmok caldera is underlain by radially anisotropic velocity structures indicating a central sill complex and a surrounding ring of dikes The path of magma through or around the central stacked sill... |
2019 |
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| 52. | Chesley, Christine; Key, Kerry; Constable, Steven; Behrens, James; MacGregor, Lucy Crustal Cracks and Frozen Flow in Oceanic Lithosphere Inferred From Electrical Anisotropy Journal Article Geochemistry Geophysics Geosystems, 20 (138), pp. 21, 2019. @article{Chesley:2019fv, title = {Crustal Cracks and Frozen Flow in Oceanic Lithosphere Inferred From Electrical Anisotropy}, author = {Christine Chesley and Kerry Key and Steven Constable and James Behrens and Lucy MacGregor}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2019/12/Chesley_et_al-2019-Geochemistry_Geophysics_Geosystems.pdf}, year = {2019}, date = {2019-12-01}, journal = {Geochemistry Geophysics Geosystems}, volume = {20}, number = {138}, pages = {21}, abstract = {Geophysical observations of anisotropy in oceanic lithosphere offer insight into the formation and evolution of tectonic plates. Seismic anisotropy is well studied but electrical anisotropy remains poorly understood, especially in the crust and uppermost mantle. Here we characterize electrical anisotropy in 33 Ma Pacific lithosphere using controlled‐source electromagnetic data that are highly sensitive to lithospheric azimuthal anisotropy. Our data reveal that the crust is ∼18–36 times more conductive in the paleo mid‐ocean ridge direction than the perpendicular paleo‐spreading direction, while in the uppermost mantle conductivity is ∼29 times higher in the paleo‐spreading direction. We propose that the crustal anisotropy results from subvertical porosity created by ridge‐parallel normal faulting during extension of the young crust and thermal stress‐driven cracking from cooling of mature crust. The magnitude of uppermost mantle anisotropy is consistent with recent experimental results showing strong electrical anisotropy in sheared olivine, suggesting its paleo‐spreading orientation results from sub‐Moho mantle shearing during plate formation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Geophysical observations of anisotropy in oceanic lithosphere offer insight into the formation and evolution of tectonic plates. Seismic anisotropy is well studied but electrical anisotropy remains poorly understood, especially in the crust and uppermost mantle. Here we characterize electrical anisotropy in 33 Ma Pacific lithosphere using controlled‐source electromagnetic data that are highly sensitive to lithospheric azimuthal anisotropy. Our data reveal that the crust is ∼18–36 times more conductive in the paleo mid‐ocean ridge direction than the perpendicular paleo‐spreading direction, while in the uppermost mantle conductivity is ∼29 times higher in the paleo‐spreading direction. We propose that the crustal anisotropy results from subvertical porosity created by ridge‐parallel normal faulting during extension of the young crust and thermal stress‐driven cracking from cooling of mature crust. The magnitude of uppermost mantle anisotropy is consistent with recent experimental results showing strong electrical anisotropy in sheared olivine, suggesting its paleo‐spreading orientation results from sub‐Moho mantle shearing during plate formation. |
| 51. | Gustafson, Chloe; Key, Kerry; Evans, Rob L Aquifer systems extending far offshore on the U.S. Atlantic margin Journal Article Scientific Reports, 9 (1), 2019. @article{freshwaterSR, title = {Aquifer systems extending far offshore on the U.S. Atlantic margin}, author = {Chloe Gustafson and Kerry Key and Rob L Evans }, url = {https://doi.org/10.1038/s41598-019-44611-7}, doi = {10.1038/s41598-019-44611-7}, year = {2019}, date = {2019-06-19}, journal = {Scientific Reports}, volume = {9}, number = {1}, abstract = {Low-salinity submarine groundwater contained within continental shelves is a global phenomenon. Mechanisms for emplacing offshore groundwater include glacial processes that drove water into exposed continental shelves during sea-level low stands and active connections to onshore hydrologic systems. While low-salinity groundwater is thought to be abundant, its distribution and volume worldwide is poorly understood due to the limited number of observations. Here we image laterally continuous aquifers extending 90 km offshore New Jersey and Martha’s Vineyard, Massachusetts, on the U.S. Atlantic margin using new shallow water electromagnetic geophysical methods. Our data provide more continuous constraints on offshore groundwater than previous models and present evidence for a connection between the modern onshore hydrologic system and offshore aquifers. We identify clinoforms as a previously unknown structural control on the lateral extent of low-salinity groundwater and potentially a control on where low-salinity water rises into the seafloor. Our data suggest a continuous submarine aquifer system spans at least 350 km of the U.S. Atlantic coast and contains about 2800 km3 of low-salinity groundwater. Our findings can be used to improve models of past glacial, eustatic, tectonic, and geomorphic processes on continental shelves and provide insight into shelf geochemistry, biogeochemical cycles, and the deep biosphere.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Low-salinity submarine groundwater contained within continental shelves is a global phenomenon. Mechanisms for emplacing offshore groundwater include glacial processes that drove water into exposed continental shelves during sea-level low stands and active connections to onshore hydrologic systems. While low-salinity groundwater is thought to be abundant, its distribution and volume worldwide is poorly understood due to the limited number of observations. Here we image laterally continuous aquifers extending 90 km offshore New Jersey and Martha’s Vineyard, Massachusetts, on the U.S. Atlantic margin using new shallow water electromagnetic geophysical methods. Our data provide more continuous constraints on offshore groundwater than previous models and present evidence for a connection between the modern onshore hydrologic system and offshore aquifers. We identify clinoforms as a previously unknown structural control on the lateral extent of low-salinity groundwater and potentially a control on where low-salinity water rises into the seafloor. Our data suggest a continuous submarine aquifer system spans at least 350 km of the U.S. Atlantic coast and contains about 2800 km3 of low-salinity groundwater. Our findings can be used to improve models of past glacial, eustatic, tectonic, and geomorphic processes on continental shelves and provide insight into shelf geochemistry, biogeochemical cycles, and the deep biosphere. |
| 50. | Werthmüller, Dieter; Key, Kerry; Slob, Evert C A tool for designing digital filters for the Hankel and Fourier transforms in potential, diffusive, and wavefield modeling Journal Article Geophysics, 84 (2), pp. F47-F56, 2019. @article{DWfilters, title = {A tool for designing digital filters for the Hankel and Fourier transforms in potential, diffusive, and wavefield modeling}, author = {Dieter Werthmüller and Kerry Key and Evert C. Slob}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2019/12/54FA3A0A-834F-4BCE-919B-18CD0E689F46.pdf}, year = {2019}, date = {2019-01-01}, journal = {Geophysics}, volume = {84}, number = {2}, pages = {F47-F56}, abstract = {ABSTRACTThe open-source code fdesign makes it possible to design digital linear filters for the Hankel and Fourier transforms used in potential, diffusive, and wavefield modeling. Digital filters can be derived for any electromagnetic (EM) method, such as methods in the diffusive limits (direct current, controlled-source EM [CSEM]) as well as methods using higher frequency content (ground-penetrating radar [GPR], acoustic and elastic wavefields). The direct matrix inversion method is used for the derivation of the filter values, and a brute-force minimization search is carried out over the defined spacing and shifting values of the filter basis. Included or user-provided theoretical transform pairs are used for the inversion. Alternatively, one can provide layered subsurface models that will be computed with a precise quadrature method using the EM modeler empymod to generate numerical transform pairs. The comparison of the presented 201 pt filter with previously presented filters indicates that it performs better for some standard CSEM cases. The derivation of a longer 2001 pt filter for a GPR example with a 250 MHz center frequency proves that the filter method works not only for diffusive EM fields but also for wave phenomena. The presented algorithm provides a tool to create problem specific digital filters. Such purpose-built filters can be made shorter and can speed up consecutive potential, diffusive, and wavefield inversions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } ABSTRACTThe open-source code fdesign makes it possible to design digital linear filters for the Hankel and Fourier transforms used in potential, diffusive, and wavefield modeling. Digital filters can be derived for any electromagnetic (EM) method, such as methods in the diffusive limits (direct current, controlled-source EM [CSEM]) as well as methods using higher frequency content (ground-penetrating radar [GPR], acoustic and elastic wavefields). The direct matrix inversion method is used for the derivation of the filter values, and a brute-force minimization search is carried out over the defined spacing and shifting values of the filter basis. Included or user-provided theoretical transform pairs are used for the inversion. Alternatively, one can provide layered subsurface models that will be computed with a precise quadrature method using the EM modeler empymod to generate numerical transform pairs. The comparison of the presented 201 pt filter with previously presented filters indicates that it performs better for some standard CSEM cases. The derivation of a longer 2001 pt filter for a GPR example with a 250 MHz center frequency proves that the filter method works not only for diffusive EM fields but also for wave phenomena. The presented algorithm provides a tool to create problem specific digital filters. Such purpose-built filters can be made shorter and can speed up consecutive potential, diffusive, and wavefield inversions. |
| 49. | Blatter, Daniel; Key, Kerry; Ray, Anandaroop; Gustafson, Chloe; Evans, Rob Bayesian Joint Inversion of Controlled Source Electromagnetic and Magnetotelluric Data to Image Freshwater Aquifer Offshore New Jersey Journal Article Geophysical Journal International, 2019, ISSN: 0956-540X. @article{10.1093/gji/ggz253, title = {Bayesian Joint Inversion of Controlled Source Electromagnetic and Magnetotelluric Data to Image Freshwater Aquifer Offshore New Jersey}, author = {Daniel Blatter and Kerry Key and Anandaroop Ray and Chloe Gustafson and Rob Evans}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2019/12/6FA32540-AE06-4DF8-93A2-E5FA1D3AAEC8.pdf}, issn = {0956-540X}, year = {2019}, date = {2019-01-01}, journal = {Geophysical Journal International}, abstract = {Joint inversion of multiple electromagnetic data sets, such as controlled source electromagnetic and magnetotelluric data, has the potential to significantly reduce uncertainty in the inverted electrical resistivity when the two data sets contain complementary information about the subsurface. However, evaluating quantitatively the model uncertainty reduction is made difficult by the fact that conventional inversion methods – using gradients and model regularization – typically produce just one model, with no associated estimate of model parameter uncertainty. Bayesian inverse methods can provide quantitative estimates of inverted model parameter uncertainty by generating an ensemble of models, sampled proportional to data fit. The resulting posterior distribution represents a combination of a priori assumptions about the model parameters and information contained in field data. Bayesian inversion is therefore able to quantify the impact of jointly inverting multiple data sets by using the statistical information contained in the posterior distribution. We illustrate, for synthetic data generated from a simple 1D model, the shape of parameter space compatible with controlled source electromagnetic and magnetotelluric data, separately and jointly. We also demonstrate that when data sets contain complementary information about the model, the region of parameter space compatible with the joint data set is less than or equal to the intersection of the regions compatible with the individual data sets. We adapt a trans-dimensional Markov chain Monte Carlo algorithm for jointly inverting multiple electromagnetic data sets for 1D Earth models and apply it to surface-towed controlled source electromagnetic and magnetotelluric data collected offshore New Jersey, USA, to evaluate the extent of a low salinity aquifer within the continental shelf. Our inversion results identify a region of high resistivity of varying depth and thickness in the upper 500 m of the continental shelf, corroborating results from a previous study that used regularized, gradient-based inversion methods. We evaluate the joint model parameter uncertainty in comparison to the uncertainty obtained from the individual data sets and demonstrate quantitatively that joint inversion offers reduced uncertainty. In addition, we show how the Bayesian model ensemble can subsequently be used to derive uncertainty estimates of pore water salinity within the low salinity aquifer.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Joint inversion of multiple electromagnetic data sets, such as controlled source electromagnetic and magnetotelluric data, has the potential to significantly reduce uncertainty in the inverted electrical resistivity when the two data sets contain complementary information about the subsurface. However, evaluating quantitatively the model uncertainty reduction is made difficult by the fact that conventional inversion methods – using gradients and model regularization – typically produce just one model, with no associated estimate of model parameter uncertainty. Bayesian inverse methods can provide quantitative estimates of inverted model parameter uncertainty by generating an ensemble of models, sampled proportional to data fit. The resulting posterior distribution represents a combination of a priori assumptions about the model parameters and information contained in field data. Bayesian inversion is therefore able to quantify the impact of jointly inverting multiple data sets by using the statistical information contained in the posterior distribution. We illustrate, for synthetic data generated from a simple 1D model, the shape of parameter space compatible with controlled source electromagnetic and magnetotelluric data, separately and jointly. We also demonstrate that when data sets contain complementary information about the model, the region of parameter space compatible with the joint data set is less than or equal to the intersection of the regions compatible with the individual data sets. We adapt a trans-dimensional Markov chain Monte Carlo algorithm for jointly inverting multiple electromagnetic data sets for 1D Earth models and apply it to surface-towed controlled source electromagnetic and magnetotelluric data collected offshore New Jersey, USA, to evaluate the extent of a low salinity aquifer within the continental shelf. Our inversion results identify a region of high resistivity of varying depth and thickness in the upper 500 m of the continental shelf, corroborating results from a previous study that used regularized, gradient-based inversion methods. We evaluate the joint model parameter uncertainty in comparison to the uncertainty obtained from the individual data sets and demonstrate quantitatively that joint inversion offers reduced uncertainty. In addition, we show how the Bayesian model ensemble can subsequently be used to derive uncertainty estimates of pore water salinity within the low salinity aquifer. |
2018 |
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| 48. | Barak, Ohad; Key, Kerry; Constable, Steven; Ronen, Shuki Recording active-seismic ground rotations using induction-coil magnetometers Journal Article Geophysics, 83 (5), pp. P19–P42, 2018. @article{Barak:2018fg, title = {Recording active-seismic ground rotations using induction-coil magnetometers}, author = {Ohad Barak and Kerry Key and Steven Constable and Shuki Ronen}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/09/Barak-et-al-Geophysics-2018.pdf}, year = {2018}, date = {2018-01-01}, journal = {Geophysics}, volume = {83}, number = {5}, pages = {P19--P42}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 47. | Blatter, Daniel; Key, Kerry; Ray, Anandaroop; Foley, Neil; Tulaczyk, Slawek; Auken, Esben Trans-dimensional Bayesian inversion of airborne transient EM data from Taylor Glacier, Antarctica Journal Article Geophysical Journal International, 214 (3), pp. 1919–1936, 2018. @article{Blatter:2018bo, title = {Trans-dimensional Bayesian inversion of airborne transient EM data from Taylor Glacier, Antarctica}, author = {Daniel Blatter and Kerry Key and Anandaroop Ray and Neil Foley and Slawek Tulaczyk and Esben Auken}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/09/GJI-Blatter-et-al-2018.pdf}, year = {2018}, date = {2018-01-01}, journal = {Geophysical Journal International}, volume = {214}, number = {3}, pages = {1919--1936}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 46. | Du, Zhijun; Key, Kerry Case study: North Sea heavy oil reservoir characterization from integrated analysis of towed-streamer EM and dual-sensor seismic data Journal Article The Leading Edge, 37 (8), pp. 608–615, 2018. @article{Du:2018kn, title = {Case study: North Sea heavy oil reservoir characterization from integrated analysis of towed-streamer EM and dual-sensor seismic data}, author = {Zhijun Du and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/09/Du-and-Key-Leading-Edge-2018.pdf}, year = {2018}, date = {2018-01-01}, journal = {The Leading Edge}, volume = {37}, number = {8}, pages = {608--615}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 45. | Naif, Samer An upper bound on the electrical conductivity of hydrated oceanic mantle at the onset of dehydration melting Journal Article Earth And Planetary Science Letters, 482 , pp. 357–366, 2018. @article{Naif:2018hk, title = {An upper bound on the electrical conductivity of hydrated oceanic mantle at the onset of dehydration melting}, author = {Samer Naif}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/09/Naif-EPSL-2018.pdf}, year = {2018}, date = {2018-01-01}, journal = {Earth And Planetary Science Letters}, volume = {482}, pages = {357--366}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2017 |
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| 44. | Siegert, Martin J; Kulessa, Bernd; Bougamont, Marion; Christoffersen, Poul; Key, Kerry; Andersen, Kristoffer R; Booth, Adam D; Smith, Andrew M Antarctic subglacial groundwater: a concept paper on its measurement and potential influence on ice flow Journal Article Geological Society, London, Special Publications, pp. SP461.8–17, 2017. @article{Anonymous:2017il, title = {Antarctic subglacial groundwater: a concept paper on its measurement and potential influence on ice flow}, author = {Martin J Siegert and Bernd Kulessa and Marion Bougamont and Poul Christoffersen and Kerry Key and Kristoffer R Andersen and Adam D Booth and Andrew M Smith}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/SP461.8.full_reduced.pdf }, year = {2017}, date = {2017-01-01}, journal = {Geological Society, London, Special Publications}, pages = {SP461.8--17}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 43. | Key, Kerry; Siegfried, Matthew R The feasibility of imaging subglacial hydrology beneath ice streams with ground-based electromagnetics Journal Article Journal of Glaciology, 331 , pp. 1–17, 2017. @article{Anonymous:2017eh, title = {The feasibility of imaging subglacial hydrology beneath ice streams with ground-based electromagnetics}, author = {Kerry Key and Matthew R Siegfried}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Key-and-Siegfried-2017.pdf}, year = {2017}, date = {2017-01-01}, journal = {Journal of Glaciology}, volume = {331}, pages = {1--17}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 42. | Attias, Eric; Evans, Rob L; Naif, Samer; Elsenbeck, Jimmy; Key, Kerry Conductivity structure of the lithosphere-asthenosphere boundary beneath the eastern North American margin Journal Article Geochemistry Geophysics Geosystems, 18 (2), pp. 676–696, 2017. @article{Attias:2017fk, title = {Conductivity structure of the lithosphere-asthenosphere boundary beneath the eastern North American margin}, author = {Eric Attias and Rob L Evans and Samer Naif and Jimmy Elsenbeck and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Attias-et-al-2017.pdf}, year = {2017}, date = {2017-01-01}, journal = {Geochemistry Geophysics Geosystems}, volume = {18}, number = {2}, pages = {676--696}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2016 |
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| 41. | Key, Kerry MARE2DEM: a 2-D inversion code for controlled-source electromagnetic and magnetotelluric data Journal Article Geophysical Journal International, 207 (1), pp. 571–588, 2016. @article{Key:2016eq, title = {MARE2DEM: a 2-D inversion code for controlled-source electromagnetic and magnetotelluric data}, author = {Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/02/GJI-Key-2016.pdf}, year = {2016}, date = {2016-01-01}, journal = {Geophysical Journal International}, volume = {207}, number = {1}, pages = {571--588}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 40. | Naif, Samer; Key, Kerry; Constable, Steven; Evans, Rob L Porosity and fluid budget of a water-rich megathrust revealed with electromagnetic data at the Middle America Trench Journal Article Geochemistry Geophysics Geosystems, 17 (11), pp. 4495–4516, 2016. @article{Naif:2016ea, title = {Porosity and fluid budget of a water-rich megathrust revealed with electromagnetic data at the Middle America Trench}, author = {Samer Naif and Kerry Key and Steven Constable and Rob L Evans}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/G3-Naif-2016.pdf}, year = {2016}, date = {2016-01-01}, journal = {Geochemistry Geophysics Geosystems}, volume = {17}, number = {11}, pages = {4495--4516}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2015 |
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| 39. | Naif, Samer; Key, Kerry; Constable, Steven; Evans, Rob L Water-rich bending faults at the Middle America Trench Journal Article Geochemistry Geophysics Geosystems, 16 (8), pp. 2582–2597, 2015. @article{Naif:2015ba, title = {Water-rich bending faults at the Middle America Trench}, author = {Samer Naif and Kerry Key and Steven Constable and Rob L Evans}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/G3-Naif-2015.pdf}, year = {2015}, date = {2015-01-01}, journal = {Geochemistry Geophysics Geosystems}, volume = {16}, number = {8}, pages = {2582--2597}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 38. | Constable, Steven; Orange, Arnold; Key, Kerry And the geophysicist replied: "Which model do you want?" Journal Article Geophysics, 80 (3), pp. E197–E212, 2015. @article{Constable:2015it, title = {And the geophysicist replied: "Which model do you want?"}, author = {Steven Constable and Arnold Orange and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-Constable-2015.pdf}, year = {2015}, date = {2015-01-01}, journal = {Geophysics}, volume = {80}, number = {3}, pages = {E197--E212}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 37. | Wheelock, Brent; Constable, Steven; Key, Kerry The advantages of logarithmically scaled data for electromagnetic inversion Journal Article Geophysical Journal International, 201 (3), pp. 1765–1780, 2015. @article{Wheelock:2015ha, title = {The advantages of logarithmically scaled data for electromagnetic inversion}, author = {Brent Wheelock and Steven Constable and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/02/Wheelock-et-al-2015.pdf}, year = {2015}, date = {2015-01-01}, journal = {Geophysical Journal International}, volume = {201}, number = {3}, pages = {1765--1780}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 36. | Hoversten, Michael G; Myer, David; Key, Kerry; Alumbaugh, David; Hermann, Oliver; Hobbet, Randall Field test of sub-basalt hydrocarbon exploration with marine controlled source electromagnetic and magnetotelluric data Journal Article Geophysical Prospecting, 63 , pp. 1284–1310, 2015. @article{Hoversten:2015ka, title = {Field test of sub-basalt hydrocarbon exploration with marine controlled source electromagnetic and magnetotelluric data}, author = {G Michael Hoversten and David Myer and Kerry Key and David Alumbaugh and Oliver Hermann and Randall Hobbet}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/02/GP-Hoversten-et-al-2015.pdf}, year = {2015}, date = {2015-01-01}, journal = {Geophysical Prospecting}, volume = {63}, pages = {1284--1310}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 35. | Myer, David; Key, Kerry; Constable, Steven Marine CSEM of the Scarborough gas field, Part 2: 2D inversion Journal Article Geophysics, 80 (3), pp. E187–E196, 2015. @article{Myer:2015bx, title = {Marine CSEM of the Scarborough gas field, Part 2: 2D inversion}, author = {David Myer and Kerry Key and Steven Constable}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-Myer-2015.pdf}, year = {2015}, date = {2015-01-01}, journal = {Geophysics}, volume = {80}, number = {3}, pages = {E187--E196}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2014 |
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| 34. | Ray, Anandaroop; Key, Kerry; Bodin, Thomas; Myer, David; Constable, Steven Bayesian inversion of marine CSEM data from the Scarborough gas field using a transdimensional 2-D parametrization Journal Article Geophysical Journal International, 199 (3), pp. 1847–1860, 2014. @article{Ray:2014jq, title = {Bayesian inversion of marine CSEM data from the Scarborough gas field using a transdimensional 2-D parametrization}, author = {Anandaroop Ray and Kerry Key and Thomas Bodin and David Myer and Steven Constable}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/GJI-Ray-2014.pdf}, year = {2014}, date = {2014-09-01}, journal = {Geophysical Journal International}, volume = {199}, number = {3}, pages = {1847--1860}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 33. | Trainor-Guitton, Whitney J; Hoversten, Michael G; Ramirez, Abelardo; Roberts, Jeffery; Juliusson, Egill; Key, Kerry; Mellors, Robert The value of spatial information for determining well placement: A geothermal example Journal Article Geophysics, 79 (5), pp. W27–W41, 2014. @article{TrainorGuitton:2014ir, title = {The value of spatial information for determining well placement: A geothermal example}, author = {Whitney J Trainor-Guitton and Michael G Hoversten and Abelardo Ramirez and Jeffery Roberts and Egill Juliusson and Kerry Key and Robert Mellors}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/02/Geophysics-Trainor-Guitton-et-al-2014.pdf}, year = {2014}, date = {2014-08-01}, journal = {Geophysics}, volume = {79}, number = {5}, pages = {W27--W41}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2013 |
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| 32. | Myer, David; Constable, Steven; Key, Kerry Magnetotelluric evidence for layered mafic intrusions beneath the Vøring and Exmouth rifted margins Journal Article Physics Of The Earth And Planetary Interiors, 220 (C), pp. 1–10, 2013. @article{Myer:2013jj, title = {Magnetotelluric evidence for layered mafic intrusions beneath the Vøring and Exmouth rifted margins}, author = {David Myer and Steven Constable and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Physics-of-the-Earth-and-Planetary-Interiors-2013-Myer.pdf}, year = {2013}, date = {2013-07-01}, journal = {Physics Of The Earth And Planetary Interiors}, volume = {220}, number = {C}, pages = {1--10}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 31. | Key, Kerry; Constable, Steven; Liu, Lijun; Pommier, Anne Electrical image of passive mantle upwelling beneath the northern East Pacific Rise Journal Article Nature, 495 (7442), pp. 499–502, 2013. @article{Key:2013gl, title = {Electrical image of passive mantle upwelling beneath the northern East Pacific Rise}, author = {Kerry Key and Steven Constable and Lijun Liu and Anne Pommier}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Nature-2013-Key.pdf}, year = {2013}, date = {2013-03-01}, journal = {Nature}, volume = {495}, number = {7442}, pages = {499--502}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 30. | Naif, Samer; Key, Kerry; Constable, Steven; Evans, Rob L Melt-rich channel observed at the lithosphere-asthenosphere boundary Journal Article Nature, 495 (7441), pp. 356–359, 2013. @article{Naif:2013gh, title = {Melt-rich channel observed at the lithosphere-asthenosphere boundary}, author = {Samer Naif and Kerry Key and Steven Constable and Rob L Evans}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Nature-2013-Naif.pdf}, year = {2013}, date = {2013-03-01}, journal = {Nature}, volume = {495}, number = {7441}, pages = {356--359}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 29. | Pommier, Anne; Evans, Rob L; Key, Kerry; Tyburczy, James A; Mackwell, Stephen; Elsenbeck, Jimmy Prediction of silicate melt viscosity from electrical conductivity: A model and its geophysical implications Journal Article Geochemistry Geophysics Geosystems, 14 (6), pp. 1685–1692, 2013. @article{Pommier:2013dc, title = {Prediction of silicate melt viscosity from electrical conductivity: A model and its geophysical implications}, author = {Anne Pommier and Rob L Evans and Kerry Key and James A Tyburczy and Stephen Mackwell and Jimmy Elsenbeck}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geochem-Geophy-Geosy-2013-Pommier.pdf}, year = {2013}, date = {2013-01-01}, journal = {Geochemistry Geophysics Geosystems}, volume = {14}, number = {6}, pages = {1685--1692}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 28. | Ray, Anandaroop; Alumbaugh, David L; Hoversten, Michael G; Key, Kerry Robust and accelerated Bayesian inversion of marine controlled-source electromagnetic data using parallel tempering Journal Article Geophysics, 78 (6), pp. E271–E280, 2013. @article{Ray:2013gz, title = {Robust and accelerated Bayesian inversion of marine controlled-source electromagnetic data using parallel tempering}, author = {Anandaroop Ray and David L Alumbaugh and Michael G Hoversten and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2013-Ray.pdf}, year = {2013}, date = {2013-01-01}, journal = {Geophysics}, volume = {78}, number = {6}, pages = {E271--E280}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 27. | Connell, Dylan; Key, Kerry A numerical comparison of time and frequency-domain marine electromagnetic methods for hydrocarbon exploration in shallow water Journal Article Geophysical Prospecting, 61 , pp. 187–199, 2013. @article{Connell:2012hs, title = {A numerical comparison of time and frequency-domain marine electromagnetic methods for hydrocarbon exploration in shallow water}, author = {Dylan Connell and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophys.-Prosp.-2013-Connell.pdf}, year = {2013}, date = {2013-01-01}, journal = {Geophysical Prospecting}, volume = {61}, pages = {187--199}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2012 |
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| 26. | Chesley, Christine; LaFemina, Peter C; Puskas, Christine; Kobayashi, Daisuke The 1707 Mw 8.7 Hoei earthquake triggered the largest historical eruption of Mt. Fuji Journal Article Geophysical Research Letters, 39 (24), pp. 5, 2012. @article{Chesley:2012fv, title = {The 1707 Mw 8.7 Hoei earthquake triggered the largest historical eruption of Mt. Fuji}, author = {Christine Chesley and Peter C. LaFemina and Christine Puskas and Daisuke Kobayashi}, doi = {https://doi.org/10.1029/2012GL053868}, year = {2012}, date = {2012-12-22}, journal = {Geophysical Research Letters}, volume = {39}, number = {24}, pages = {5}, abstract = {[1] Studies in magma‐tectonics point to a spatiotemporal correlation between earthquakes and volcanic eruptions. Here, we examine the correlation between two great Japanese earthquakes, the 1703 Mw 8.2 Genroku and 1707 Mw 8.7 Hoei, and Mt. Fuji's explosive (VEI 5) Hoei eruption, 49 days after the 1707 earthquake. We model the static stress changes and dilatational strain imparted on the Mt. Fuji magmatic system due to each earthquake to determine if these mechanisms enhanced the potential for eruption. Our results show that both earthquakes clamped the dike from 8 km to the surface and compressed magma chambers at 8 km and 20 km depths. The 1707 earthquake decreased the normal stress on the dike at 20 km, the proposed depth of a basaltic magma chamber, by 1.06 bars (0.106 MPa). We hypothesize that the stress change and strain generated by the 1707 earthquake triggered the eruption of Mt. Fuji by permitting opening of the dike and ascent of basaltic magma from 20 km into andesitic and dacitic magma chambers located at 8 km depth. The injection of basaltic magma into the more evolved magmatic system induced magma mixing and a Plinian eruption ensued.}, keywords = {}, pubstate = {published}, tppubtype = {article} } [1] Studies in magma‐tectonics point to a spatiotemporal correlation between earthquakes and volcanic eruptions. Here, we examine the correlation between two great Japanese earthquakes, the 1703 Mw 8.2 Genroku and 1707 Mw 8.7 Hoei, and Mt. Fuji's explosive (VEI 5) Hoei eruption, 49 days after the 1707 earthquake. We model the static stress changes and dilatational strain imparted on the Mt. Fuji magmatic system due to each earthquake to determine if these mechanisms enhanced the potential for eruption. Our results show that both earthquakes clamped the dike from 8 km to the surface and compressed magma chambers at 8 km and 20 km depths. The 1707 earthquake decreased the normal stress on the dike at 20 km, the proposed depth of a basaltic magma chamber, by 1.06 bars (0.106 MPa). We hypothesize that the stress change and strain generated by the 1707 earthquake triggered the eruption of Mt. Fuji by permitting opening of the dike and ascent of basaltic magma from 20 km into andesitic and dacitic magma chambers located at 8 km depth. The injection of basaltic magma into the more evolved magmatic system induced magma mixing and a Plinian eruption ensued. |
| 25. | Key, Kerry; Constable, Steven; Matsuno, Tetsuo; Evans, Rob L; Myer, David Electromagnetic detection of plate hydration due to bending faults at the Middle America Trench Journal Article Earth And Planetary Science Letters, 351-352 , pp. 45–53, 2012. @article{Key:2012ei, title = {Electromagnetic detection of plate hydration due to bending faults at the Middle America Trench}, author = {Kerry Key and Steven Constable and Tetsuo Matsuno and Rob L Evans and David Myer}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Earth-Planet-Sc-Lett-2012-Key.pdf}, year = {2012}, date = {2012-10-01}, journal = {Earth And Planetary Science Letters}, volume = {351-352}, pages = {45--53}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 24. | Selway, Kate; Thiel, Stephan; Key, Kerry A simple 2-D explanation for negative phases in TE magnetotelluric data Journal Article Geophysical Journal International, 188 , pp. 945–958, 2012. @article{Selway:2012jy, title = {A simple 2-D explanation for negative phases in TE magnetotelluric data}, author = {Kate Selway and Stephan Thiel and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophys-J-Int-2012-Selway.pdf}, year = {2012}, date = {2012-01-01}, journal = {Geophysical Journal International}, volume = {188}, pages = {945--958}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 23. | Ray, Anandaroop; Key, Kerry Bayesian inversion of marine CSEM data with a trans-dimensional self parametrizing algorithm Journal Article Geophysical Journal International, 191 (3), pp. 1135–1151, 2012. @article{Ray:2012fk, title = {Bayesian inversion of marine CSEM data with a trans-dimensional self parametrizing algorithm}, author = {Anandaroop Ray and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophys-J-Int-2012-Ray.pdf}, year = {2012}, date = {2012-01-01}, journal = {Geophysical Journal International}, volume = {191}, number = {3}, pages = {1135--1151}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 22. | Myer, David; Constable, Steven; Key, Kerry; Glinsky, Michael E; Liu, Guimin Marine CSEM of the Scarborough gas field, Part 1: Experimental design and data uncertainty Journal Article Geophysics, 77 (4), pp. E281–E299, 2012. @article{Myer:2012jo, title = {Marine CSEM of the Scarborough gas field, Part 1: Experimental design and data uncertainty}, author = {David Myer and Steven Constable and Kerry Key and Michael E Glinsky and Guimin Liu}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2012-Myer.pdf}, year = {2012}, date = {2012-01-01}, journal = {Geophysics}, volume = {77}, number = {4}, pages = {E281--E299}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 21. | Chen, Jinsong; Hoversten, Michael G; Key, Kerry; Nordquist, Gregg; Cumming, William Stochastic inversion of magnetotelluric data using a sharp boundary parameterization and application to a geothermal site Journal Article Geophysics, 77 (4), pp. E265, 2012. @article{Chen:2012bp, title = {Stochastic inversion of magnetotelluric data using a sharp boundary parameterization and application to a geothermal site}, author = {Jinsong Chen and Michael G Hoversten and Kerry Key and Gregg Nordquist and William Cumming}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2012-Chen.pdf}, year = {2012}, date = {2012-01-01}, journal = {Geophysics}, volume = {77}, number = {4}, pages = {E265}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 20. | Brown, Vanessa; Hoversten, Mike; Key, Kerry; Chen, Jinsong Resolution of reservoir scale electrical anisotropy from marine CSEM data Journal Article Geophysics, 77 (2), pp. E147–E158, 2012. @article{Brown:2012iw, title = {Resolution of reservoir scale electrical anisotropy from marine CSEM data}, author = {Vanessa Brown and Mike Hoversten and Kerry Key and Jinsong Chen}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2012-Brown-1.pdf}, year = {2012}, date = {2012-01-01}, journal = {Geophysics}, volume = {77}, number = {2}, pages = {E147--E158}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 19. | Key, Kerry Is the fast Hankel transform faster than quadrature? Journal Article Geophysics, 77 (3), pp. F21–F30, 2012. @article{Key:2012ku, title = {Is the fast Hankel transform faster than quadrature?}, author = {Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2012-Key.pdf}, year = {2012}, date = {2012-01-01}, journal = {Geophysics}, volume = {77}, number = {3}, pages = {F21--F30}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 18. | Brown, Vanessa; Key, Kerry; Singh, Satish Seismically regularized controlled-source electromagnetic inversion Journal Article Geophysics, 77 (1), pp. E57–E65, 2012. @article{Brown:2012wx, title = {Seismically regularized controlled-source electromagnetic inversion}, author = {Vanessa Brown and Kerry Key and Satish Singh}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2012-Brown.pdf}, year = {2012}, date = {2012-01-01}, journal = {Geophysics}, volume = {77}, number = {1}, pages = {E57–E65}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 17. | Shahin, Alireza; Key, Kerry; Stoffa, Paul; Tatham, Robert Petro-electric modeling for CSEM reservoir characterization and monitoring Journal Article Geophysics, 77 (1), pp. E9–E20, 2012. @article{Shahin:2012hx, title = {Petro-electric modeling for CSEM reservoir characterization and monitoring}, author = {Alireza Shahin and Kerry Key and Paul Stoffa and Robert Tatham}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2012-Shahin.pdf}, year = {2012}, date = {2012-01-01}, journal = {Geophysics}, volume = {77}, number = {1}, pages = {E9--E20}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 16. | Key, Kerry Marine electromagnetic studies of seafloor resources and tectonics Journal Article Surveys In Geophysics, 33 (1), pp. 135–167, 2012. @article{Key:B7OWU_Hn, title = {Marine electromagnetic studies of seafloor resources and tectonics}, author = {Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Surv-Geophys-2012-Key.pdf}, year = {2012}, date = {2012-01-01}, journal = {Surveys In Geophysics}, volume = {33}, number = {1}, pages = {135--167}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2011 |
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| 15. | Key, Kerry; Constable, Steven Coast effect distortion of marine magnetotelluric data: Insights from a pilot study offshore northeastern Japan Journal Article Physics of the Earth Planetary Interiors, 184 (3-4), pp. 194–207, 2011. @article{Key:2011jw, title = {Coast effect distortion of marine magnetotelluric data: Insights from a pilot study offshore northeastern Japan}, author = {Kerry Key and Steven Constable}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/2011-Key-1.pdf}, year = {2011}, date = {2011-02-01}, journal = {Physics of the Earth Planetary Interiors}, volume = {184}, number = {3-4}, pages = {194--207}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 14. | Myer, David; Constable, Steven; Key, Kerry Broad-band waveforms and robust processing for marine CSEM surveys Journal Article Geophysical Journal International, 184 , pp. 689–698, 2011. @article{Myer:2010gy, title = {Broad-band waveforms and robust processing for marine CSEM surveys}, author = {David Myer and Steven Constable and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophys-J-Int-2011-Myer.pdf}, year = {2011}, date = {2011-01-01}, journal = {Geophysical Journal International}, volume = {184}, pages = {689--698}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 13. | Zhdanov, Michael S; Wan, Le; Gribenko, Alexander; Cuma, Martin; Key, Kerry; Constable, Steven Large-scale 3D inversion of marine magnetotelluric data: Case study from the Gemini prospect, Gulf of Mexico Journal Article Geophysics, 76 (1), pp. F77–F87, 2011. @article{Zhdanov:2011ku, title = {Large-scale 3D inversion of marine magnetotelluric data: Case study from the Gemini prospect, Gulf of Mexico}, author = {Michael S Zhdanov and Le Wan and Alexander Gribenko and Martin Cuma and Kerry Key and Steven Constable}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2011-Zhdanov.pdf}, year = {2011}, date = {2011-01-01}, journal = {Geophysics}, volume = {76}, number = {1}, pages = {F77--F87}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 12. | Key, Kerry; Ovall, Jeffrey A parallel goal-oriented adaptive finite element method for 2.5-D electromagnetic modelling Journal Article Geophysical Journal International, 186 (1), pp. 137–154, 2011. @article{GJI:GJI5025, title = {A parallel goal-oriented adaptive finite element method for 2.5-D electromagnetic modelling}, author = {Kerry Key and Jeffrey Ovall}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophys-J-Int-2011-Key.pdf}, year = {2011}, date = {2011-01-01}, journal = {Geophysical Journal International}, volume = {186}, number = {1}, pages = {137--154}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2010 |
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| 11. | Key, Kerry; Lockwood, Andrew Determining the orientation of marine CSEM receivers using orthogonal Procrustes rotation analysis Journal Article Geophysics, 75 (3), pp. F63–F70, 2010. @article{key:F63, title = {Determining the orientation of marine CSEM receivers using orthogonal Procrustes rotation analysis}, author = {Kerry Key and Andrew Lockwood}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2010-Key.pdf}, year = {2010}, date = {2010-01-01}, journal = {Geophysics}, volume = {75}, number = {3}, pages = {F63--F70}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2009 |
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| 10. | Orange, Arnold; Key, Kerry; Constable, Steven The feasibility of reservoir monitoring using time-lapse marine CSEM Journal Article Geophysics, 74 (2), pp. F21–F29, 2009. @article{orange:F21, title = {The feasibility of reservoir monitoring using time-lapse marine CSEM}, author = {Arnold Orange and Kerry Key and Steven Constable}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2009-Orange.pdf}, year = {2009}, date = {2009-01-01}, journal = {Geophysics}, volume = {74}, number = {2}, pages = {F21--F29}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 9. | Key, Kerry 1D inversion of multicomponent, multifrequency marine CSEM data: Methodology and synthetic studies for resolving thin resistive layers Journal Article Geophysics, 74 (2), pp. F9–F20, 2009. @article{key:F9, title = {1D inversion of multicomponent, multifrequency marine CSEM data: Methodology and synthetic studies for resolving thin resistive layers}, author = {Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2009-Key.pdf}, year = {2009}, date = {2009-01-01}, journal = {Geophysics}, volume = {74}, number = {2}, pages = {F9--F20}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 8. | Constable, Steven; Key, Kerry; Lewis, Lisl Mapping offshore sedimentary structure using electromagnetic methods and terrain effects in marine magnetotelluric data Journal Article Geophysical Journal International, 176 (2), pp. 431–442, 2009. @article{SDTrough, title = {Mapping offshore sedimentary structure using electromagnetic methods and terrain effects in marine magnetotelluric data}, author = {Steven Constable and Kerry Key and Lisl Lewis}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophys-J-Int-2009-Constable.pdf}, year = {2009}, date = {2009-01-01}, journal = {Geophysical Journal International}, volume = {176}, number = {2}, pages = {431--442}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2007 |
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| 7. | Li, Yuguo; Key, Kerry 2D marine controlled-source electromagnetic modeling: Part 1–An adaptive finite element algorithm Journal Article Geophysics, 72 (2), pp. WA51–WA62, 2007. @article{LiKey2007, title = {2D marine controlled-source electromagnetic modeling: Part 1–An adaptive finite element algorithm}, author = {Yuguo Li and Kerry Key}, url = {http://emlab.ldeo.columbia.edu/wp-content/uploads/2018/01/Geophysics-2007-Li.pdf}, year = {2007}, date = {2007-03-01}, journal = {Geophysics}, volume = {72}, number = {2}, pages = {WA51--WA62}, keywords = {}, pubstate = {published}, tppubtype = {article} } |