Satellite data sets are an asset in global gravity collections;their characteristics vary in coverage and resolution. New collections appear often, and the user must adapt fast to their characteristics. Their use in g...Satellite data sets are an asset in global gravity collections;their characteristics vary in coverage and resolution. New collections appear often, and the user must adapt fast to their characteristics. Their use in geophysical modeling is rapidly increasing;with this in mind we compare two of the most densely populated sets: EIGEN-6C4 and GGMplus. We characterize them in terms of their frequency histograms, Free Air anomalies, power spectrum, and simple Bouguer anomalies. The nature of the digital elevation models used for data reduction is discussed. We conclude that the GGMplus data set offers a better spatial resolution. To evaluate their effect in geophysical modelling, we chose an inland region with a prominent volcanic structure in which we perform 3D inversions of the respective Bouguer anomalies, obtaining density variations that in principle can be associated with the geologic materials and the structure of the volcanic edifice. Model results are analyzed along sections of the inverted data;we conclude that the GGMplus data set offers higher resolution in the cases analyzed.展开更多
The Hunga Tonga Hunga Ha’apai submarine volcano has experienced repeated eruptions in the latest decades.The recent one,in January 2022,released an enormous amount of energy inducing global perturbations,as tsunamis ...The Hunga Tonga Hunga Ha’apai submarine volcano has experienced repeated eruptions in the latest decades.The recent one,in January 2022,released an enormous amount of energy inducing global perturbations,as tsunamis and atmospheric waves.The structure of the volcano is poorly understood,especially its internal structure.Deep-seated magmatic connections are difficult to define or visualize.We use a high-resolution gravity data set obtained via satellite to calculate the Bouguer anomaly over its structure,to perform a preliminary exploration of its interior.Executing 3D gravity inversions,we find a complex plumbing system with various exhaust trajectories and multiple surface pockets of low-density material within the volcanic edifice;some appear to be associated with ring fractures.This is in line with the report of the 2009 eruption,described as beginning from multiple vents.We found no signs of a magma chamber within 6 km depth,although several volcanic conduits are identified from such depth to the surface.Density variations occur within a plumbing conduit or may vary from one conduit to another in the same volcano.These models yield quantitative estimates for areas of magma-water interaction,constituting a baseline to compare with structural changes to be induced in future eruptions.展开更多
Transmission through seemingly opaque surfaces,so-called extraordinary transmission,provides an exciting platform for strong light–matter interaction,spectroscopy,optical trapping,and color filtering.Much of the effo...Transmission through seemingly opaque surfaces,so-called extraordinary transmission,provides an exciting platform for strong light–matter interaction,spectroscopy,optical trapping,and color filtering.Much of the effort has been devoted to understanding and exploiting TM extraordinary transmission,while TE anomalous extraordinary transmission has been largely omitted in the literature.This is regrettable from a practical point of view since the stronger dependence of the TE anomalous extraordinary transmission on the array’s substrate provides additional design parameters for exploitation.To provide high-performance and cost-effective applications based on TE anomalous extraordinary transmission,a complete physical insight about the underlying mechanisms of the phenomenon must be first laid down.To this end,resorting to a combined methodology including quasi-optical terahertz(THz)time-domain measurements,full-wave simulations,and method of moments analysis,subwavelength slit arrays under s-polarized illumination are studied here,filling the void in the current literature.We believe this work unequivocally reveals the leaky-wave role of the grounded-dielectric slab mode mediating in TE anomalous extraordinary transmission and provides the necessary framework to design practical high-performance THz components and systems.展开更多
文摘Satellite data sets are an asset in global gravity collections;their characteristics vary in coverage and resolution. New collections appear often, and the user must adapt fast to their characteristics. Their use in geophysical modeling is rapidly increasing;with this in mind we compare two of the most densely populated sets: EIGEN-6C4 and GGMplus. We characterize them in terms of their frequency histograms, Free Air anomalies, power spectrum, and simple Bouguer anomalies. The nature of the digital elevation models used for data reduction is discussed. We conclude that the GGMplus data set offers a better spatial resolution. To evaluate their effect in geophysical modelling, we chose an inland region with a prominent volcanic structure in which we perform 3D inversions of the respective Bouguer anomalies, obtaining density variations that in principle can be associated with the geologic materials and the structure of the volcanic edifice. Model results are analyzed along sections of the inverted data;we conclude that the GGMplus data set offers higher resolution in the cases analyzed.
基金support from the Consejo Nacional de Ciencia y Tecnología(CONACYT,México)supported by Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas,Universidad Nacional Autónoma de México。
文摘The Hunga Tonga Hunga Ha’apai submarine volcano has experienced repeated eruptions in the latest decades.The recent one,in January 2022,released an enormous amount of energy inducing global perturbations,as tsunamis and atmospheric waves.The structure of the volcano is poorly understood,especially its internal structure.Deep-seated magmatic connections are difficult to define or visualize.We use a high-resolution gravity data set obtained via satellite to calculate the Bouguer anomaly over its structure,to perform a preliminary exploration of its interior.Executing 3D gravity inversions,we find a complex plumbing system with various exhaust trajectories and multiple surface pockets of low-density material within the volcanic edifice;some appear to be associated with ring fractures.This is in line with the report of the 2009 eruption,described as beginning from multiple vents.We found no signs of a magma chamber within 6 km depth,although several volcanic conduits are identified from such depth to the surface.Density variations occur within a plumbing conduit or may vary from one conduit to another in the same volcano.These models yield quantitative estimates for areas of magma-water interaction,constituting a baseline to compare with structural changes to be induced in future eruptions.
基金Engineering and Physical Sciences Research Council(EP/L015331/1,EP/S018395/1,2137478)Russian Foundation for Basic Research(18-29-20066)+3 种基金Ministerio de Ciencia,Innovación y Universidades(RTI2018-094475-B-I00)Royal Society(RSG/R1/180040)University of Birmingham(Birmingham Fellowship)Ministerio de Ciencia,Innovación y Universidades(TEC2017-84724-P)。
文摘Transmission through seemingly opaque surfaces,so-called extraordinary transmission,provides an exciting platform for strong light–matter interaction,spectroscopy,optical trapping,and color filtering.Much of the effort has been devoted to understanding and exploiting TM extraordinary transmission,while TE anomalous extraordinary transmission has been largely omitted in the literature.This is regrettable from a practical point of view since the stronger dependence of the TE anomalous extraordinary transmission on the array’s substrate provides additional design parameters for exploitation.To provide high-performance and cost-effective applications based on TE anomalous extraordinary transmission,a complete physical insight about the underlying mechanisms of the phenomenon must be first laid down.To this end,resorting to a combined methodology including quasi-optical terahertz(THz)time-domain measurements,full-wave simulations,and method of moments analysis,subwavelength slit arrays under s-polarized illumination are studied here,filling the void in the current literature.We believe this work unequivocally reveals the leaky-wave role of the grounded-dielectric slab mode mediating in TE anomalous extraordinary transmission and provides the necessary framework to design practical high-performance THz components and systems.
