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Articles 31 - 60 of 355
Full-Text Articles in Earth Sciences
Adequately Reflecting The Severity Of Tropical Cyclones Using The New Tropical Cyclone Severity Scale, Nadia Bloemendaal, Hans De Moel, Jantsje M. Mol, Priscilla R.M. Bosma, Amy Polen, Jennifer M. Collins
Adequately Reflecting The Severity Of Tropical Cyclones Using The New Tropical Cyclone Severity Scale, Nadia Bloemendaal, Hans De Moel, Jantsje M. Mol, Priscilla R.M. Bosma, Amy Polen, Jennifer M. Collins
School of Geosciences Faculty and Staff Publications
For decades, meteorologists and governments have been warning communities in coastal areas for an imminent tropical cyclone (TC) using the Saffir-Simpson Hurricane Wind Scale (SSHWS). The SSHWS categorizes a TC based on its maximum wind speed, and is used in defining evacuation strategies and humanitarian response. However, the SSHWS considers only the wind hazard of a TC, whereas a TC can also cause severe conditions through its high storm surges and extreme rainfall, triggering coastal and inland flooding. Consequently, the SSHWS fails to mirror the TC's total severity. This becomes evident when looking at past events such as Hurricane Harvey …
Magma Source Evolution Following Subduction Initiation: Evidence From The Element Concentrations, Stable Isotope Ratios, And Water Contents Of Volcanic Glasses From The Bonin Forearc (Iodp Expedition 352), Daniel A. Coulthard, Mark K. Reagan, Kenji Shimizu, Ilya N. Bindeman, Maryjo Brounce, Renat R. Almeev, Jeffrey Ryan, Timothy Chapman, John Shervais, Julian A. Pearce
Magma Source Evolution Following Subduction Initiation: Evidence From The Element Concentrations, Stable Isotope Ratios, And Water Contents Of Volcanic Glasses From The Bonin Forearc (Iodp Expedition 352), Daniel A. Coulthard, Mark K. Reagan, Kenji Shimizu, Ilya N. Bindeman, Maryjo Brounce, Renat R. Almeev, Jeffrey Ryan, Timothy Chapman, John Shervais, Julian A. Pearce
School of Geosciences Faculty and Staff Publications
International Ocean Discovery Program Expedition 352 to the Bonin forearc drilled the sequence of volcanic rocks erupted in the immediate aftermath of subduction initiation along the western margin of the Pacific Plate. Pristine volcanic glasses collected during this expedition were analyzed for major and trace elements, halogens, sulfur, and H and O isotopes with goals of characterizing the fluids and melts of subducted materials that were involved in generating the nascent upper plate crust. Incompatible trace element compositions of the oldest lavas (forearc basalts [FAB]) are similar to those of the most depleted mid‐ocean ridge basalts globally. Most FAB were …
Formation Mechanisms Of Macroscopic Globules In Andesitic Glasses From The Izu–Bonin–Mariana Forearc (Iodp Expedition 352), Raúl O.C. Fonseca, Lina T. Michely, Maria Kirchenbaur, Julie Prytulak, Jeffrey Ryan, Kerstin Hauke, Felipe P. Leitzke, Renat R. Almeev, Chris S. Marien, Axel Gerdes, Rico Schellhorn
Formation Mechanisms Of Macroscopic Globules In Andesitic Glasses From The Izu–Bonin–Mariana Forearc (Iodp Expedition 352), Raúl O.C. Fonseca, Lina T. Michely, Maria Kirchenbaur, Julie Prytulak, Jeffrey Ryan, Kerstin Hauke, Felipe P. Leitzke, Renat R. Almeev, Chris S. Marien, Axel Gerdes, Rico Schellhorn
School of Geosciences Faculty and Staff Publications
The Izu–Bonin–Mariana volcanic arc is situated at a convergent plate margin where subduction initiation triggered the formation of MORB-like forearc basalts as a result of decompression melting and near-trench spreading. International Ocean Discovery Program (IODP) Expedition 352 recovered samples within the forearc basalt stratigraphy that contained unusual macroscopic globular textures hosted in andesitic glass (Unit 6, Hole 1440B). It is unclear how these andesites, which are unique in a stratigraphic sequence dominated by forearc basalts, and the globular textures therein may have formed. Here, we present detailed textural evidence, major and trace element analysis, as well as B and Sr …
Machine Learning Approaches To Identifying Changes In Eruptive State Using Multi-Parameter Datasets From The 2006 Eruption Of Augustine Volcano, Alaska, Grace F. Manley, Tamsin A. Mather, David M. Pyle, David A. Clifton, Mel Rodgers, Glenn Thompson, Diana C. Roman
Machine Learning Approaches To Identifying Changes In Eruptive State Using Multi-Parameter Datasets From The 2006 Eruption Of Augustine Volcano, Alaska, Grace F. Manley, Tamsin A. Mather, David M. Pyle, David A. Clifton, Mel Rodgers, Glenn Thompson, Diana C. Roman
School of Geosciences Faculty and Staff Publications
Understanding the timing of critical changes in volcanic systems, such as the beginning and end of eruptive behavior, is a key goal of volcanic monitoring. Traditional approaches to forecasting these changes have used models motivated by the underlying physics of eruption onset, which assume that geophysical precursors will consistently display similar patterns prior to transition in volcanic state. We present a machine learning classification approach for detecting significant changes in patterns of volcanic activity, potentially signaling transitions during the onset or end of volcanic activity, which does not require a model of the physical processes underlying critical changes. We apply …
Exploring Best Practices In Geoscience Education: Adapting A Video/Animation On Continental Rifting For Upper-Division Students To A Lower-Division Audience, Siloa Willis, Robert J. Stern, Jeffrey Ryan, Christy Bebeau
Exploring Best Practices In Geoscience Education: Adapting A Video/Animation On Continental Rifting For Upper-Division Students To A Lower-Division Audience, Siloa Willis, Robert J. Stern, Jeffrey Ryan, Christy Bebeau
School of Geosciences Faculty and Staff Publications
Well-crafted and scientifically accurate videos and animations can be effective ways to teach dynamic Earth processes such as continental rifting, both in live course offerings as well as in online settings. However, a quick search of the internet reveals too few high-quality videos/animations describing deep Earth processes. We have modified a hybrid 10.5 min video/animation about continental rifting and the formation of new oceans and passive continental margins created for an upper-division geology audience, retailoring it for a lower-division geology audience. A key challenge in successfully modifying such resources is aligning the cognitive load that the video/animation imposes on students, …
Monochromatic Long-Period Seismicity Prior To The 2012 Earthquake Swarm At Little Sitkin Volcano, Alaska, Matthew M. Haney, Helena Buurman, Stephen Holtkamp, Stephen R. Mcnutt
Monochromatic Long-Period Seismicity Prior To The 2012 Earthquake Swarm At Little Sitkin Volcano, Alaska, Matthew M. Haney, Helena Buurman, Stephen Holtkamp, Stephen R. Mcnutt
School of Geosciences Faculty and Staff Publications
Detection of the earliest stages of unrest is one of the most challenging and yet critically needed aspects of volcano monitoring. We investigate a sequence of five unusual long-period (LP) earthquakes that occurred in the days prior to the onset of a months-long volcano-tectonic (VT) earthquake swarm beneath Little Sitkin volcano in the Aleutian Islands during late 2012. The long-period earthquakes had two distinctive characteristics: their signals were dominated by a monochromatic spectral peak at approximately 0.57 Hz and they had impulsive P and S-wave arrivals on a seismometer located on Amchitka Island 80 km to the southeast of the …
Socioeconomic Challenges Of California Strawberry Production And Disease Resistant Cultivars, Julie Guthman, Estelí Jiménez-Soto
Socioeconomic Challenges Of California Strawberry Production And Disease Resistant Cultivars, Julie Guthman, Estelí Jiménez-Soto
School of Geosciences Faculty and Staff Publications
Strawberries are the 4th highest grossing crop in California and supply 90% of US strawberries. But the industry's long reliance on the use of chemical fumigants to control soil disease, nematodes and weeds is being threatened by increased regulation of these fumigants, leading to urgent efforts to develop and test non-chemical alternatives to fumigation, such as disease resistant cultivars. Many of these technologies are promising ecologically, but making them economically viable for growers is more challenging, especially in light of the socioeconomic context of strawberry production in California that has created a state of lock-in for a sustainability transition. This …
The Radius Of The Umbrella Cloud Helps Characterize Large Explosive Volcanic Eruptions, Robert Constantinescu, Aurelian Hopulele-Gligor, Charles Connor, Costanza Bonadonna, Laura Connor, Jan Lindsay, Sylvain Charbonnier, Alain C.M. Volentik
The Radius Of The Umbrella Cloud Helps Characterize Large Explosive Volcanic Eruptions, Robert Constantinescu, Aurelian Hopulele-Gligor, Charles Connor, Costanza Bonadonna, Laura Connor, Jan Lindsay, Sylvain Charbonnier, Alain C.M. Volentik
School of Geosciences Faculty and Staff Publications
Eruption source parameters (in particular erupted volume and column height) are used by volcanologists to inform volcanic hazard assessments and to classify explosive volcanic eruptions. Estimations of source parameters are associated with large uncertainties due to various factors, including complex tephra sedimentation patterns from gravitationally spreading umbrella clouds. We modify an advection-diffusion model to investigate this effect. Using this model, source parameters for the climactic phase of the 2450 BP eruption of Pululagua, Ecuador, are different with respect to previous estimates (erupted mass: 1.5–5 × 1011 kg, umbrella cloud radius: 10–14 km, plume height: 20–30 km). We suggest large …
Magmatic Response To Subduction Initiation, Part Ii: Boninites And Related Rocks Of The Izu‐Bonin Arc From Iopd Expedition 352, John W. Shervais, Mark K. Reagan, Marguerite Godard, Julie Prytulak, Jeffrey G. Ryan
Magmatic Response To Subduction Initiation, Part Ii: Boninites And Related Rocks Of The Izu‐Bonin Arc From Iopd Expedition 352, John W. Shervais, Mark K. Reagan, Marguerite Godard, Julie Prytulak, Jeffrey G. Ryan
School of Geosciences Faculty and Staff Publications
International Ocean Discovery Program Expedition 352 to the Izu‐Bonin forearc cored over 800 m of basement comprising boninite and boninite‐series lavas. This is the most extensive, well‐constrained suite of boninite series lavas ever obtained from in situ oceanic crust. The boninites are characterized as high‐silica boninite (HSB), low‐silica boninite (LSB), or basaltic boninite based on their SiO2‐MgO‐TiO2 relations. The principal fractionation products of all three series are high‐Mg andesites (HMA). Lavas recovered >250 meters below seafloor (mbsf) erupted at a forearc spreading axis and are dominated by LSB and HMA. Lavas recovered fromoff‐axis and are dominated by …
Linking Landscape Attributes To Salmon And Decision-Making In The Southern Kenai Lowlands, Alaska, Usa, Coowe M. Walker, Dennis F. Whigham, I. Syverine Bentz, Jacob M. Argueta, Ryan S. King, Mark C. Rains, Charles A. Simenstad, Chris Guo, Steven J. Baird, Conrad J. Field
Linking Landscape Attributes To Salmon And Decision-Making In The Southern Kenai Lowlands, Alaska, Usa, Coowe M. Walker, Dennis F. Whigham, I. Syverine Bentz, Jacob M. Argueta, Ryan S. King, Mark C. Rains, Charles A. Simenstad, Chris Guo, Steven J. Baird, Conrad J. Field
School of Geosciences Faculty and Staff Publications
While Pacific salmon are economically and culturally important worldwide, Alaska, USA is one of the few remaining places on earth where sustainable management of salmon is possible, even in the face of wide-ranging threats, including overharvesting and the impacts of climate change. A continuing challenge that we face is to understand the ecological processes that result in sustainable salmon populations and report that science to stakeholders in a way that promotes decision-making to avoid the destruction of salmon populations that has occurred in most areas of the lower 48 states. To address this challenge, our studies in the southern Kenai …
Ethical Product Havens In The Global Diamond Trade: Using The Wayback Machine To Evaluate Ethical Market Outcomes, Trina Hamilton, Seth Cavello
Ethical Product Havens In The Global Diamond Trade: Using The Wayback Machine To Evaluate Ethical Market Outcomes, Trina Hamilton, Seth Cavello
School of Geosciences Faculty and Staff Publications
Who benefits from ethical product markets? While most ethical products (e.g. fair trade and eco-certified products) are intended to benefit marginalized communities and vulnerable ecosystems, the reality is that the geographic preferences exhibited by so-called ethical markets may, in fact, reinforce global inequities rather than remedy them. It can be difficult to evaluate the outcomes of ethical product markets, however, because we are often limited to data from a small number of industries with widely used standards and certifications. This research pilots a new methodology, using an online archive—the Wayback Machine, to evaluate shifts in countries' ethical market share, focusing …
Impulsive Volcanic Plumes Generate Volcanic Lightning And Vent Discharges: A Statistical Analysis Of Sakurajima Volcano In 2015, Cassandra M. Smith, Damien Gaudin, Alexa R. Van Eaton, Sonja A. Behnke, Steven Reader, Ronald J. Thomas, Harald Edens, Stephen R. Mcnutt, Corrado Cimarelli
Impulsive Volcanic Plumes Generate Volcanic Lightning And Vent Discharges: A Statistical Analysis Of Sakurajima Volcano In 2015, Cassandra M. Smith, Damien Gaudin, Alexa R. Van Eaton, Sonja A. Behnke, Steven Reader, Ronald J. Thomas, Harald Edens, Stephen R. Mcnutt, Corrado Cimarelli
School of Geosciences Faculty and Staff Publications
The origin of electrical activity accompanying volcanic ash plumes is an area of heightened interest in volcanology. However, it is unclear how intense an eruption needs to be to produce lightning flashes as opposed to “vent discharges,” which represent the smallest scale of electrical activity. This study targets 97 carefully monitored plumesJapan, from June 1 to 7, 2015. We use multiparametric measurements from sensors including a nine-station lightning mapping array and an infrared camera to characterize plume ascent. Findings demonstrate that the impulsive, high velocity plumes (>55 m/s) were most likely to create vent discharges, whereas lightning flashes occurred …
Molybdenum Isotopes Unmask Slab Dehydration And Melting Beneath The Mariana Arc, Hong-Yan Li, Rui-Peng Zhao, Jie Li, Yoshihiko Tamura, Christopher Spencer, Robert J. Stern, Jeffrey G. Ryan, Yi-Gang Xu
Molybdenum Isotopes Unmask Slab Dehydration And Melting Beneath The Mariana Arc, Hong-Yan Li, Rui-Peng Zhao, Jie Li, Yoshihiko Tamura, Christopher Spencer, Robert J. Stern, Jeffrey G. Ryan, Yi-Gang Xu
School of Geosciences Faculty and Staff Publications
How serpentinites in the forearc mantle and subducted lithosphere become involved in enriching the subarc mantle source of arc magmas is controversial. Here we report molybdenum isotopes for primitive submarine lavas and serpentinites from active volcanoes and serpentinite mud volcanoes in the Mariana arc. These data, in combination with radiogenic isotopes and elemental ratios, allow development of a model whereby shallow, partially serpentinized and subducted forearc mantle transfers fluid and melt from the subducted slab into the subarc mantle. These entrained forearc mantle fragments are further metasomatized by slab fluids/melts derived from the dehydration of serpentinites in the subducted lithospheric …
Large-Volume And Shallow Magma Intrusions In The Blackfoot Reservoir Volcanic Field (Idaho, Usa), M. S. Hastings, C. B. Connor, P. Wetmore, R. Malservisi, L. J. Connor, M. Rodgers, P. C. Femina
Large-Volume And Shallow Magma Intrusions In The Blackfoot Reservoir Volcanic Field (Idaho, Usa), M. S. Hastings, C. B. Connor, P. Wetmore, R. Malservisi, L. J. Connor, M. Rodgers, P. C. Femina
School of Geosciences Faculty and Staff Publications
he Blackfoot Reservoir volcanic field (BRVF), Idaho, USA, is a bimodal volcanic field that has hosted silicic eruptions during at least two episodes, as recently as 58 ka. Using newly collected ground and boat-based gravity data, two large negative anomalies (-16 mGal) are modeled as shallow (< 1 km) intrusions beneath a NE-trending alignment of BRVF rhyolite domes and tuff rings. Given the trade-off between density contrast and model volume, best-fit gravity inversion models yield a total intrusion volume of 50-120 km3; a density contrast of -400 kg m-3 results in two intrusions, each ~9 km x 4.5 km and about 0.5 km thick, with cumulative volume of 100 km3. A network of 340°-360° trending faults lies directly above and on the margins of the mapped gravity anomalies. Most of …
A Preliminary Exploration Of The Cooling Effect Of Tree Shade In Urban Landscapes, Qiuyan Yu, Wenjie Ji, Ruiliang Pu, Shawn Landry, Michael Acheampong, Jarlath O'Neil-Dunne, Zhibin Ren, Shakhawat H. Tanim
A Preliminary Exploration Of The Cooling Effect Of Tree Shade In Urban Landscapes, Qiuyan Yu, Wenjie Ji, Ruiliang Pu, Shawn Landry, Michael Acheampong, Jarlath O'Neil-Dunne, Zhibin Ren, Shakhawat H. Tanim
School of Geosciences Faculty and Staff Publications
Mitigating urban heat island (UHI) effects, especially under climate change, is necessary for the promotion of urban sustainability. Shade is one of the most important functions provided by urban trees for mitigating UHI. However, the cooling effect of tree shade has not been adequately investigated. In this study, we used a simple and straightforward method to quantify the spatial and temporal variation of tree shade and examined its effect on land surface temperature (LST). We used the hillshade function in a geographic information system to quantify the spatiotemporal patterns of tree shade by integrating sun location and tree height. Relationships …
Examining The Statistical Relationships Between Volcanic Seismic, Infrasound, And Electrical Signals: A Case Study Of Sakurajima Volcano, 2015, Cassandra M. Smith, Glenn Thompson, Steven Reader, Sonja A. Behnke, Stephen R. Mcnutt, Ron Thomas, Harald Edens
Examining The Statistical Relationships Between Volcanic Seismic, Infrasound, And Electrical Signals: A Case Study Of Sakurajima Volcano, 2015, Cassandra M. Smith, Glenn Thompson, Steven Reader, Sonja A. Behnke, Stephen R. Mcnutt, Ron Thomas, Harald Edens
School of Geosciences Faculty and Staff Publications
Sakurajima volcano in Japan is known for frequent eruptions containing prolific volcanic lightning. Previous studies from eruptions at Redoubt have shown preliminary correlations between seismic, infrasound, and radio frequency signals. This study uses field data collected at Sakurajima from 28 May–7 June 2015 and multivariable statistical modeling to quantify these relationships. We build regression equations to examine each of the following parameters of electrical activity: (1) the presence of electrical activity, (2) the presence of the radio frequency signal called continual radio frequency impulses (CRF), (3) the presence of lightning, (4) the overall duration of electrical activity, and (5) the …
Geophysical And Social Influences On Evacuation Decision-Making: The Case Of Hurricane Irma, Robin Ersing, Christianne Pearce, Jennifer M. Collins, Michelle E. Saunders, Amy Polen
Geophysical And Social Influences On Evacuation Decision-Making: The Case Of Hurricane Irma, Robin Ersing, Christianne Pearce, Jennifer M. Collins, Michelle E. Saunders, Amy Polen
School of Geosciences Faculty and Staff Publications
Understanding the factors that influence evacuation decision-making among local residents is of critical importance to those involved in monitoring and managing weather-related hazards. This study examined both geophysical and social variables that we believe influenced individual decision-making on whether to stay home, seek out a public shelter, or leave the area entirely during Hurricane Irma. A 23-item survey was administered to a convenience sample of adults (n = 234) who resided within a coastal Florida county that received an evacuation warning during Hurricane Irma in 2017. Results suggested sources of information relied on through media, government, family, and social networks …
Pystprism: Tools For Voxel-Based Space–Time Prisms, Rebecca Loraamm, Joni A. Downs, James Anderson, David S. Lamb
Pystprism: Tools For Voxel-Based Space–Time Prisms, Rebecca Loraamm, Joni A. Downs, James Anderson, David S. Lamb
School of Geosciences Faculty and Staff Publications
The observed movements of humans and animals are realizations of complex spatiotemporal processes. Recent advances in location-aware technologies have rendered trajectory data ubiquitous. Examining the sequenced, instantaneous locations found in movement trajectory data for information reconstructing the location or state of the mover between observed points comprises a primary focus in Time Geography and related disciplines. The PySTPrism toolbox introduced in this paper provides a straightforward and open-source implementation of the Probabilistic Space Time Prism, in addition to related tools from Time Geography. PySTPrism is implemented in Python using the ArcPy module in ArcGIS Pro Desktop.
Dynamics And Impacts Of The May 8th, 1902 Pyroclastic Current At Mount Pelée (Martinique): New Insights From Numerical Modeling, Valentin Gueugneau, Karim Kelfoun, Sylvain J. Charbonnier, Aurelie Germa, Guillaume Carazzo
Dynamics And Impacts Of The May 8th, 1902 Pyroclastic Current At Mount Pelée (Martinique): New Insights From Numerical Modeling, Valentin Gueugneau, Karim Kelfoun, Sylvain J. Charbonnier, Aurelie Germa, Guillaume Carazzo
School of Geosciences Faculty and Staff Publications
The Mount Pelée May 8th, 1902 eruption is responsible for the deaths of more than 29,000 people, as well as the nearly-complete destruction of the city of Saint Pierre by a single pyroclastic current, and is, sadly, the deadliest eruption of the 20th century. Despite intensive field studies on the associated deposit, two conflicting interpretations of the pyroclastic current dynamics (either a blast or a simple ash-cloud surge) emerged in the 90’s and have been paralyzing research ever since, leaving numerous unknowns (i.e., source conditions, volume). This study is the first to investigate numerically the May 8th, 1902 pyroclastic …
Novel Quantification Of Shallow Sediment Compaction By Gps Interferometric Reflectometry And Implications For Flood Susceptibility, Makan A. Karegar, Kristine M. Larson, Jurgen Kusche, Timothy H. Dixon
Novel Quantification Of Shallow Sediment Compaction By Gps Interferometric Reflectometry And Implications For Flood Susceptibility, Makan A. Karegar, Kristine M. Larson, Jurgen Kusche, Timothy H. Dixon
School of Geosciences Faculty and Staff Publications
Estimates of flood susceptibility and land loss in the world's coastal regions depend on our knowledge of sea level rise (SLR) from increases in ocean mass and volume, as well as knowledge of vertical land motion. Conventional approaches to the latter include tide‐gauge and Global Positioning System (GPS) measurements relative to well‐anchored monuments few meters below the surface. However, in regions of rapid Holocene sedimentation, compaction of this material can add a significant component to the surface lowering. Unfortunately, this process has been difficult to quantify, especially for the shallowest material above the monument. Here we use a new technique, …
Evaluating The Influences Of Harvesting Activity And Eutrophication On Loss Of Aquatic Vegetations In Taihu Lake, China, Juhua Luo, Ruiliang Pu, Hongtao Duan, Ronghua Ma, Zhigang Mao, Yuan Zeng, Linsheng Huang, Qitao Xiao
Evaluating The Influences Of Harvesting Activity And Eutrophication On Loss Of Aquatic Vegetations In Taihu Lake, China, Juhua Luo, Ruiliang Pu, Hongtao Duan, Ronghua Ma, Zhigang Mao, Yuan Zeng, Linsheng Huang, Qitao Xiao
School of Geosciences Faculty and Staff Publications
A rapid degradation of aquatic vegetations in Taihu Lake has roused a wide attention in recent years. Giving large-scale harvesting activity on aquatic vegetation since 2012, whether water eutrophication or the human harvest activity induced the degradation remains controversial and unclear. In this study, based on Landsat and HJ-CCD data acquired from 1984 to 2016 and a 12-year field observation (2005–2016) of water quality, a method was proposed to quantitatively assess impacts of harvesting activity and water quality change on degradations of both floating-leaved aquatic vegetation (FAV) and submerged aquatic vegetation (SAV) in Taihu Lake. First, areas of FAV and …
Resolution Of Lava Tubes With Ground Penetrating Radar: The Tubex Project, Sanaz Esmaeili, Sarah Kruse, Sajad Jazayeri, P. Whelley, E. Bell, J. Richardson, W. B. Garry, K. Young
Resolution Of Lava Tubes With Ground Penetrating Radar: The Tubex Project, Sanaz Esmaeili, Sarah Kruse, Sajad Jazayeri, P. Whelley, E. Bell, J. Richardson, W. B. Garry, K. Young
School of Geosciences Faculty and Staff Publications
Remote sensing surveys of the Moon and Mars show evidence of lava tubes, which are potential safe havens for human crews and their equipment. Ground penetrating radar (GPR) can be used to map tubes because the void/rock interface at tube ceilings and floors strongly reflects radar pulses. We have tested the capacity of GPR to sense lava tube geometry at Lava Beds National Monument in California, USA. GPR and detailed light detection and ranging (LiDAR) data are presented for two tubes: Skull Cave, with a few meters of overburden, diameter ~10–20 m, and a rubbly floor; and Valentine Cave, with …
Biogenic Silica And Organic Carbon Records In Zhoushan Coastal Sea Over The Past One Hundred Years And Their Environmental Indications, Hao Xu, Shangwei Jiang, Jialin Li, Ruiliang Pu, Jia Wang, Wanghai Jin, Longbin Sha, Dongling Li
Biogenic Silica And Organic Carbon Records In Zhoushan Coastal Sea Over The Past One Hundred Years And Their Environmental Indications, Hao Xu, Shangwei Jiang, Jialin Li, Ruiliang Pu, Jia Wang, Wanghai Jin, Longbin Sha, Dongling Li
School of Geosciences Faculty and Staff Publications
The influence of terrestrial and marine input has dramatically changed eutrophication in coastal seas over the past 100 years. In this study, Zhoushan coastal sea (ZCS) is taken as a study area. We studied ZCS as it is a sink of the temporal and spatial variation of primary productivity, dominant species of algae, and the variation of provenance in this area over the past 100 years. We performed analysis using three sediment cores and the carbon and silicon deposition records. The analysis results demonstrate that: (1) The primary productivity in the northern area of the ZCS close to the Yangtze …
Surface Deformation And Induced Seismicity Due To Fluid Injection And Oil And Gas Extraction In Western Texas, Fanghui Deng, Timothy H. Dixon, Surui Xie
Surface Deformation And Induced Seismicity Due To Fluid Injection And Oil And Gas Extraction In Western Texas, Fanghui Deng, Timothy H. Dixon, Surui Xie
School of Geosciences Faculty and Staff Publications
Texas is experiencing increasing seismicity, likely related to the oil and gas production process. We used satellite InSAR (Interferometric Synthetic Aperture Radar) to monitor surface deformation at three study sites in western Texas with similar geologic characteristics. The deformation data were compared to earthquake distribution, groundwater changes, volumes of produced and injected fluid, and calculated pore pressure change and Coulomb failure stress change to assess causes of deformation and seismicity. Site 1 experienced surface uplift due to fluid injection but no increase in seismicity. The average media properties were estimated based on the deformation using a poroelastic model. Site 2 …
Modeling The Contribution Of Poroelastic Deformation To Postseismic Geodetic Signals, Kimberly Mccormack, Marc A. Hesse, Timothy H. Dixon, Rocco Malservisi
Modeling The Contribution Of Poroelastic Deformation To Postseismic Geodetic Signals, Kimberly Mccormack, Marc A. Hesse, Timothy H. Dixon, Rocco Malservisi
School of Geosciences Faculty and Staff Publications
To constrain the poroelastic component of postseismic deformation, we model the subsurface hydrologic response to the Mw 7.6 subduction zone earthquake that occurred on the plate interface beneath the Nicoya peninsula in Costa Rica on 5 September 2012. The model shows that poroelastic relaxation occurs on multiple time scales and the associated deformation can be up to 2 cm for the trench‐perpendicular component. By modeling the time‐dependent deformation associated with poroelastic relaxation, we can begin to remove its contribution from the observed geodetic signal. Inversions for after slip that ignore poroelastic deformation have errors of 10–20% overall and up …
Estimation Of Aboveground Biomass Of Robinia Pseudoacacia Forest In The Yellow River Delta Based On Uav And Backpack Lidar Point Clouds, Jinbo Lu, Hong Wang, Shuhong Qin, Lin Cao, Ruiliang Pu, Guilin Li, Jing Sun
Estimation Of Aboveground Biomass Of Robinia Pseudoacacia Forest In The Yellow River Delta Based On Uav And Backpack Lidar Point Clouds, Jinbo Lu, Hong Wang, Shuhong Qin, Lin Cao, Ruiliang Pu, Guilin Li, Jing Sun
School of Geosciences Faculty and Staff Publications
Forest plantations are an important source of terrestrial carbon sequestration. The forest of Robinia pseudoacacia in the Yellow River Delta (YRD) is the largest artificial ecological protection forest in China. However, more than half of the forest has appeared different degrees of dieback and even death since the 1990s. Timely and accurate estimation of the forest aboveground biomass (AGB) is a basis for studying the carbon cycle of forests. Light Detecting and Ranging (LiDAR) has been proved to be one of the most powerful methods for forest biomass estimation. However, because of an irregular and overlapping shape of the broadleaved …
Quantifying Rates Of “Rifting While Drifting” In The Southern Gulf Of California: The Role Of The Southern Baja California Microplate And Its Eastern Boundary Zone, Paul J. Umhoefer, C. Plattner, Rocco Malservisi
Quantifying Rates Of “Rifting While Drifting” In The Southern Gulf Of California: The Role Of The Southern Baja California Microplate And Its Eastern Boundary Zone, Paul J. Umhoefer, C. Plattner, Rocco Malservisi
School of Geosciences Faculty and Staff Publications
The southern Baja California (Mexico) microplate has been rapidly moving away from the North America plate since ca. 12 Ma. This relative motion toward the northwest developed an oblique-divergent plate boundary that formed the Gulf of California. The rift-drift hypothesis postulates that when a continent ruptures and seafloor spreading commences, rifting on the plate margins ceases, and the margins start to drift, subside, and accumulate postrift sediments, eventually becoming a passive margin. In contrast to this hypothesis, the southern part of the Baja California microplate (BCM), and in particular its actively deforming eastern boundary zone, has continued significant rifting for …
Mariana Serpentinite Mud Volcanism Exhumes Subducted Seamount Materials: Implications For The Origin Of Life, Patricia Freyer, C. G. Wheat, Trevor Williams, Christopher Kelley, Kevin Johnson, Jeffrey Ryan, Walter Kurz, John Shervais, Elmar Albers, Barbara Bekins
Mariana Serpentinite Mud Volcanism Exhumes Subducted Seamount Materials: Implications For The Origin Of Life, Patricia Freyer, C. G. Wheat, Trevor Williams, Christopher Kelley, Kevin Johnson, Jeffrey Ryan, Walter Kurz, John Shervais, Elmar Albers, Barbara Bekins
School of Geosciences Faculty and Staff Publications
The subduction of seamounts and ridge features at convergent plate boundaries plays an important role in the deformation of the overriding plate and influences geochemical cycling and associated biological processes. Active serpentinization of forearc mantle and serpentinite mud volcanism on the Mariana forearc (between the trench and active volcanic arc) provides windows on subduction processes. Here, we present (1) the first observation of an extensive exposure of an undeformed Cretaceous seamount currently being subducted at the Mariana Trench inner slope; (2) vertical deformation of the forearc region related to subduction of Pacific Plate seamounts and thickened crust; (3) recovered Ocean …
Scientist Of The Week!, Sarah L. Sheffield, Lisette Melendez, Kristin Houdyshell, Mathew Burgos
Scientist Of The Week!, Sarah L. Sheffield, Lisette Melendez, Kristin Houdyshell, Mathew Burgos
School of Geosciences Faculty and Staff Publications
No abstract provided.
Space-Time Hierarchical Clustering For Identifying Clusters In Spatiotemporal Point Data, David S. Lamb, Joni Downs, Steven Reader
Space-Time Hierarchical Clustering For Identifying Clusters In Spatiotemporal Point Data, David S. Lamb, Joni Downs, Steven Reader
School of Geosciences Faculty and Staff Publications
Finding clusters of events is an important task in many spatial analyses. Both confirmatory and exploratory methods exist to accomplish this. Traditional statistical techniques are viewed as confirmatory, or observational, in that researchers are confirming an a priori hypothesis. These methods often fail when applied to newer types of data like moving object data and big data. Moving object data incorporates at least three parts: location, time, and attributes. This paper proposes an improved space-time clustering approach that relies on agglomerative hierarchical clustering to identify groupings in movement data. The approach, i.e., space–time hierarchical clustering, incorporates location, time, and attribute …