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https://www.readbyqxmd.com/read/29144459/geophysics-the-buoyancy-of-earth-s-deep-mantle
#1
Barbara Romanowicz
No abstract text is available yet for this article.
November 15, 2017: Nature
https://www.readbyqxmd.com/read/29144451/tidal-tomography-constrains-earth-s-deep-mantle-buoyancy
#2
Harriet C P Lau, Jerry X Mitrovica, James L Davis, Jeroen Tromp, Hsin-Ying Yang, David Al-Attar
Earth's body tide-also known as the solid Earth tide, the displacement of the solid Earth's surface caused by gravitational forces from the Moon and the Sun-is sensitive to the density of the two Large Low Shear Velocity Provinces (LLSVPs) beneath Africa and the Pacific. These massive regions extend approximately 1,000 kilometres upward from the base of the mantle and their buoyancy remains actively debated within the geophysical community. Here we use tidal tomography to constrain Earth's deep-mantle buoyancy derived from Global Positioning System (GPS)-based measurements of semi-diurnal body tide deformation...
November 15, 2017: Nature
https://www.readbyqxmd.com/read/29142259/drip-tectonics-and-the-enigmatic-uplift-of-the-central-anatolian-plateau
#3
Oğuz H Göğüş, Russell N Pysklywec, A M C Şengör, Erkan Gün
Lithospheric drips have been interpreted for various regions around the globe to account for the recycling of the continental lithosphere and rapid plateau uplift. However, the validity of such hypothesis is not well documented in the context of geological, geophysical and petrological observations that are tested against geodynamical models. Here we propose that the folding of the Central Anatolian (Kırşehir) arc led to thickening of the lithosphere and onset of "dripping" of the arc root. Our geodynamic model explains the seismic data showing missing lithosphere and a remnant structure characteristic of a dripping arc root, as well as enigmatic >1 km uplift over the entire plateau, Cappadocia and Galatia volcanism at the southern and northern plateau margins since ~10 Ma, respectively...
November 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/29129913/volcanism-in-slab-tear-faults-is-larger-than-in-island-arcs-and-back-arcs
#4
Luca Cocchi, Salvatore Passaro, Fabio Caratori Tontini, Guido Ventura
Subduction-transform edge propagators are lithospheric tears bounding slabs and back-arc basins. The volcanism at these edges is enigmatic because it is lacking comprehensive geological and geophysical data. Here we present bathymetric, potential-field data, and direct observations of the seafloor on the 90 km long Palinuro volcanic chain overlapping the E-W striking tear of the roll-backing Ionian slab in Southern Tyrrhenian Sea. The volcanic chain includes arc-type central volcanoes and fissural, spreading-type centers emplaced along second-order shears...
November 13, 2017: Nature Communications
https://www.readbyqxmd.com/read/29125556/integration-of-gis-electromagnetic-and-electrical-methods-in-the-delimitation-of-groundwater-polluted-by-effluent-discharge-salamanca-spain-a-case-study
#5
Rubén Vidal Montes, Antonio Miguel Martínez-Graña, José Ramón Martínez Catalán, Puy Ayarza Arribas, Francisco Javier Sánchez San Román, Caridad Zazo
The present work envisages the possible geometry of a contaminated plume of groundwater near hospital facilities by combining GIS (Geographic Information System) and geophysical methods. The rock underlying the soil and thin sedimentary cover of the study area is moderately fractured quartzite, which makes aquifers vulnerable to pollution. The GIS methodology is used to calculate the area that would be affected by the effluent source of residual water, based on algorithms that consider ground surface mapping (slopes, orientations, accumulated costs and cost per distance)...
November 10, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/29104259/a-review-of-hybrid-fiber-optic-distributed-simultaneous-vibration-and-temperature-sensing-technology-and-its-geophysical-applications
#6
REVIEW
Khalid Miah, David K Potter
Distributed sensing systems can transform an optical fiber cable into an array of sensors, allowing users to detect and monitor multiple physical parameters such as temperature, vibration and strain with fine spatial and temporal resolution over a long distance. Fiber-optic distributed acoustic sensing (DAS) and distributed temperature sensing (DTS) systems have been developed for various applications with varied spatial resolution, and spectral and sensing range. Rayleigh scattering-based phase optical time domain reflectometry (OTDR) for vibration and Raman/Brillouin scattering-based OTDR for temperature and strain measurements have been developed over the past two decades...
November 1, 2017: Sensors
https://www.readbyqxmd.com/read/29092450/methods-for-removal-of-unwanted-signals-from-gravity-time-series-comparison-using-linear-techniques-complemented-with-analysis-of-system-dynamics
#7
Arthur Valencio, Celso Grebogi, Murilo S Baptista
The presence of undesirable dominating signals in geophysical experimental data is a challenge in many subfields. One remarkable example is surface gravimetry, where frequencies from Earth tides correspond to time-series fluctuations up to a thousand times larger than the phenomena of major interest, such as hydrological gravity effects or co-seismic gravity changes. This work discusses general methods for the removal of unwanted dominating signals by applying them to 8 long-period gravity time-series of the International Geodynamics and Earth Tides Service, equivalent to the acquisition from 8 instruments in 5 locations representative of the network...
October 2017: Chaos
https://www.readbyqxmd.com/read/29079732/monitoring-ground-water-storage-at-mesoscale-using-seismic-noise-30-years-of-continuous-observation-and-thermo-elastic-and-hydrological-modeling
#8
Thomas Lecocq, Laurent Longuevergne, Helle Anette Pedersen, Florent Brenguier, Klaus Stammler
Groundwater is a vital freshwater resource for both humans and ecosystems. Achieving sustainable management requires a detailed knowledge of the aquifer structure and of its behavior in response to climatic and anthropogenic forcing. Traditional monitoring is carried out using piezometer networks, and recently complemented with new geophysical or satellite-based observations. These techniques survey either local (small-scale) water systems or regional areas (large scale) but, to date, adequate observation tools are lacking at the water management scale (i...
October 27, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29076986/design-of-a-matching-network-for-a-high-sensitivity-broadband-magnetic-resonance-sounding-coil-sensor
#9
Yang Zhang, Fei Teng, Suhang Li, Ling Wan, Tingting Lin
The magnetic resonance sounding (MRS) technique is a non-invasive geophysical method that can provide unique insights into the hydrological properties of groundwater. The Cu coil sensor is the preferred choice for detecting the weak MRS signal because of its high sensitivity, low fabrication complexity and low cost. The tuned configuration was traditionally used for the MRS coil sensor design because of its high sensitivity and narrowband filtering. However, its narrow bandwidth may distort the MRS signals...
October 27, 2017: Sensors
https://www.readbyqxmd.com/read/29073053/geophysical-potential-for-wind-energy-over-the-open-oceans
#10
Anna Possner, Ken Caldeira
Wind turbines continuously remove kinetic energy from the lower troposphere, thereby reducing the wind speed near hub height. The rate of electricity generation in large wind farms containing multiple wind arrays is, therefore, constrained by the rate of kinetic energy replenishment from the atmosphere above. In recent years, a growing body of research argues that the rate of generated power is limited to around 1.5 W m(-2) within large wind farms. However, in this study, we show that considerably higher power generation rates may be sustainable over some open ocean areas...
October 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29067642/arctic-climate-change-economy-and-society-access-integrated-perspectives
#11
Anne-Sophie Crépin, Michael Karcher, Jean-Claude Gascard
This introduction to the special issue presents an overview of the wide range of results produced during the European Union project Arctic Climate Change, Economy and Society (ACCESS). This project assessed the main impacts of climate change on Arctic Ocean's geophysical variables and how these impending changes could be expected to impact directly and indirectly on socio-economic activities like transportation, marine sea food production and resource exploitation. Related governance issues were examined. These results were used to develop several management tools that can live on beyond ACCESS...
October 24, 2017: Ambio
https://www.readbyqxmd.com/read/29066745/mantle-hydration-along-outer-rise-faults-inferred-from-serpentinite-permeability
#12
Kohei Hatakeyama, Ikuo Katayama, Ken-Ichi Hirauchi, Katsuyoshi Michibayashi
Recent geophysical surveys indicate that hydration (serpentinization) of oceanic mantle is related to outer-rise faulting prior to subduction. The serpentinization of oceanic mantle influences the generation of intermediate-depth earthquakes and subduction water flux, thereby promoting arc volcanism. Since the chemical reactions that produce serpentinite are geologically rapid at low temperatures, the flux of water delivery to the reaction front appears to control the lateral extent of serpentinization. In this study, we measured the permeability of low-temperature serpentinites composed of lizardite and chrysotile, and calculated the lateral extent of serpentinization along an outer-rise fault based on Darcy's law...
October 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29059569/analysis-and-modelling-of-surface-urban-heat-island-in-20-canadian-cities-under-climate-and-land-cover-change
#13
Abhishek Gaur, Markus Kalev Eichenbaum, Slobodan P Simonovic
Surface Urban Heat Island (SUHI) is an urban climate phenomenon that is expected to respond to future climate and land-use land-cover change. It is important to further our understanding of physical mechanisms that govern SUHI phenomenon to enhance our ability to model future SUHI characteristics under changing geophysical conditions. In this study, SUHI phenomenon is quantified and modelled at 20 cities distributed across Canada. By analyzing MODerate Resolution Imaging Spectroradiometer (MODIS) sensed surface temperature at the cities over 2002-2012, it is found that 16 out of 20 selected cities have experienced a positive SUHI phenomenon while 4 cities located in the prairies region and high elevation locations have experienced a negative SUHI phenomenon in the past...
October 20, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/29057878/the-impact-of-anthropogenic-land-use-and-land-cover-change-on-regional-climate-extremes
#14
Kirsten L Findell, Alexis Berg, Pierre Gentine, John P Krasting, Benjamin R Lintner, Sergey Malyshev, Joseph A Santanello, Elena Shevliakova
Land surface processes modulate the severity of heat waves, droughts, and other extreme events. However, models show contrasting effects of land surface changes on extreme temperatures. Here, we use an earth system model from the Geophysical Fluid Dynamics Laboratory to investigate regional impacts of land use and land cover change on combined extremes of temperature and humidity, namely aridity and moist enthalpy, quantities central to human physiological experience of near-surface climate. The model's near-surface temperature response to deforestation is consistent with recent observations, and conversion of mid-latitude natural forests to cropland and pastures is accompanied by an increase in the occurrence of hot-dry summers from once-in-a-decade to every 2-3 years...
October 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/29056383/deglaciation-and-its-impact-on-permafrost-and-rock-glacier-evolution-new-insight-from-two-adjacent-cirques-in-austria
#15
Andreas Kellerer-Pirklbauer, Viktor Kaufmann
Glaciers and permafrost are strongly linked to each other in mid-latitude mountain regions particularly with polythermal glaciers. This linkage is not only climatically defined but also in terms of geomorphic and glaciological processes. We studied two adjacent cirques located in the Central Austria. We focussed on the deglaciation since the Little Ice Age (LIA) maximum (c.1850CE) and its relevance for permafrost and rock glacier evolution since then. One cirque is occupied by a glacier remnant whereas the second one is occupied by an active rock glacier which was partly overridden by a glacier during the LIA...
October 20, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29042647/ultrasensitive-high-dynamic-range-and-broadband-strain-sensing-by-time-of-flight-detection-with-femtosecond-laser-frequency-combs
#16
Xing Lu, Shuangyou Zhang, Xing Chen, Dohyeon Kwon, Chan-Gi Jeon, Zhigang Zhang, Jungwon Kim, Kebin Shi
Ultrahigh-resolution optical strain sensors provide powerful tools in various scientific and engineering fields, ranging from long-baseline interferometers to civil and aerospace industries. Here we demonstrate an ultrahigh-resolution fibre strain sensing method by directly detecting the time-of-flight (TOF) change of the optical pulse train generated from a free-running passively mode-locked laser (MLL) frequency comb. We achieved a local strain resolution of 18 pε/Hz(1/2) and 1.9 pε/Hz(1/2) at 1 Hz and 3 kHz, respectively, with large dynamic range of >154 dB at 3 kHz...
October 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29036925/evaluating-oilseed-biofuel-production-feasibility-in-california-s-san-joaquin-valley-using-geophysical-and-remote-sensing-techniques
#17
Dennis L Corwin, Kevin Yemoto, Wes Clary, Gary Banuelos, Todd H Skaggs, Scott M Lesch, Elia Scudiero
Though more costly than petroleum-based fuels and a minor component of overall military fuel sources, biofuels are nonetheless strategically valuable to the military because of intentional reliance on multiple, reliable, secure fuel sources. Significant reduction in oilseed biofuel cost occurs when grown on marginally productive saline-sodic soils plentiful in California's San Joaquin Valley (SJV). The objective is to evaluate the feasibility of oilseed production on marginal soils in the SJV to support a 115 ML yr(-1) biofuel conversion facility...
October 14, 2017: Sensors
https://www.readbyqxmd.com/read/29036501/multi-year-monitoring-of-radon-in-boreholes-at-the-modra-geophysical-observatory-slovakia
#18
I Smetanová, G Steinitz, K Holý
Long-term radon monitoring was performed in two boreholes, at a depth of 13 m in the 40 m deep V-2 borehole (August 2003-September 2005), and at 3 m depth in the 10 m deep V-3 borehole (August 2003-April 2008). Diurnal, multi-day and annual variations in radon time-series were observed. Daily average of radon activity in V-2 borehole was significantly higher and ranged from 6.5 to 383.7 kBq/m3, while in V-3 borehole only between 1.2 and 139.4 kBq/m3. The seasonal pattern was more pronounced in V-3 time series, with the maximum occurring from October to March...
September 19, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29036347/signal-decomposition-and-analysis-for-the-identification-of-periodic-and-anomalous-phenomena-in-radon-time-series
#19
C Sabbarese, F Ambrosino, F De Cicco, M Pugliese, M Quarto, V Roca
This work concerns continuous monitoring of radon and thoron specific activity in soil gas within the framework of identifying possible anomalies. It is based on the analysis of a medium-term data record obtained from soil gas in an area of geophysical interest. The RaMonA spectrometric system is also used to measure the climatic parameters and a specific analysis of the alpha spectra is performed to better determine the alpha lines intensity. Since radon emission is also influenced by meteorological parameters, it is mandatory to differentiate the changes due to the deep phenomena...
September 23, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29021556/unexpected-3-valence-of-iron-in-feo2-a-geologically-important-material-lying-in-between-oxides-and-peroxides
#20
Sergey S Streltsov, Alexey O Shorikov, Sergey L Skornyakov, Alexander I Poteryaev, Daniel I Khomskii
Recent discovery of the pyrite FeO2, which can be an important ingredient of the Earth's lower mantle and which in particular may serve as an extra source of water in the Earth's interior, opens new perspectives for geophysics and geochemistry, but this is also an extremely interesting material from physical point of view. We found that in contrast to naive expectations Fe is nearly 3+ in this material, which strongly affects its magnetic properties and makes it qualitatively different from well known sulfide analogue - FeS2...
October 11, 2017: Scientific Reports
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