Geophysics and Seismology Commons^™

Understanding The Effect Of Fire On Vegetation Composition And Gross Primary Production In A Semi-Arid Shrubland Ecosystem Using The Ecosystem Demography (Edv2.2) Model, Karun Pandit, Hamid Dashti, Andrew T. Hudak, Nancy F. Glenn, Alejandro N. Flores, Douglas J. Shinneman

Geosciences Faculty Publications and Presentations

Wildfires in sagebrush (Artemisia spp.)-dominated semi-arid ecosystems in the western United States have increased dramatically in frequency and severity in the last few decades. Severe wildfires often lead to the loss of native sagebrush communities and change the biogeochemical conditions which make it difficult for sagebrush to regenerate. Invasion of cheatgrass (Bromus tectorum) accentuates the problem by making the ecosystem more susceptible to frequent burns. Managers have implemented several techniques to cope with the cheatgrass–fire cycle, ranging from controlling undesirable fire effects by removing fuel loads either mechanically or via prescribed burns to seeding the fire-affected areas …

Seismic Anisotropy And Mantle Deformation Beneath The Central Sunda Plate, Wenkai Song, Youqiang Yu, Stephen S. Gao, Kelly H. Liu, Yifang Fu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The central Sunda plate, which forms the core of Southeast Asia, has been extensively studied based on analyses of data mainly from surface geological observations. In contrast, largely due to the limited coverage by seismic stations in the area, a number of key issues associated with mantle structure and dynamics remain enigmatic. These can possibly be constrained by investigating seismic azimuthal anisotropy in the upper mantle. Here we employ the shear wave splitting technique on three P-to-S converted phases from the core-mantle boundary (PKS, SKKS, and SKS) recorded by 11 stations to systematically explore the spatial variation of azimuthal anisotropy …

Snow Avalanche Detection And Source Constraints Made Using A Networked Array Of Infrasound Sensors, J. B. Johnson, J. F. Anderson, H. P. Marshall, S. Havens, L. M. Watson

Geosciences Faculty Publications and Presentations

We studied a triggered snow avalanche (∼60 s in duration and with ∼1,100 m run-out) using a network of infrasound arrays and time-synced video, with the objective of understanding the relationship between infrasound generation and flow dynamics. Using standard array processing techniques, we compared the infrasound source back azimuths with the avalanche flow path identified by frame-differenced, geo-referenced video. Results show that infrasound records begin with direct arrivals followed by echoes from the avalanche-triggering explosions and these decay within 35 s of the detonations. Subsequent infrasound, which lasts 20–30 s, could then be attributed exclusively to the avalanche. These infrasound …

The 31 March 2020 MW 6.5 Stanley, Idaho, Earthquake: Seismotectonics And Preliminary Aftershock Analysis, Lee M. Liberty, Zachary M. Lifton, T. Dylan Mikesell

Geosciences Faculty Publications and Presentations

We report on the tectonic framework, seismicity, and aftershock monitoring efforts related to the 31 March 2020 M_w 6.5 Stanley, Idaho, earthquake. The earthquake sequence has produced both strike-slip and dip-slip motion, with minimal surface displacement or damage. The earthquake occurred at the northern limits of the Sawtooth normal fault. This fault separates the Centennial tectonic belt, a zone of active seismicity within the Basin and Range Province, from the Idaho batholith to the west and Challis volcanic belt to the north and east. We show evidence for a potential kinematic link between the northeast-dipping Sawtooth fault and the …

Geology Study – Drilling Down At Red Trail Energy, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about a 2019–2020 geophysical survey near Richardton, North Dakota. The survey investigated the area’s feasibility as a CO₂ storage site, as part of the Red Trail Energy carbon capture and storage (CCS) research effort. Summarizes survey process and results. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]

Snow Ensemble Uncertainty Project (Seup): Quantification Of Snow Water Equivalent Uncertainty Across North America Via Ensemble Land Surface Modeling, Hans-Peter Marshall

Geosciences Faculty Publications and Presentations

The Snow Ensemble Uncertainty Project (SEUP) is an effort to establish a baseline characterization of snow water equivalent (SWE) uncertainty across North America with the goal of informing global snow observational needs. An ensemble-based modeling approach, encompassing a suite of current operational models is used to assess the uncertainty in SWE and total snow storage (SWS) estimation over North America during the 2009–2017 period. The highest modeled SWE uncertainty is observed in mountainous regions, likely due to the relatively deep snow, forcing uncertainties, and variability between the different models in resolving the snow processes over complex terrain. This highlights a …

From Hector Mine M7.1 To Ridgecrest M7.1 Earthquake. A Look From A 20-Year Perspective, Sergey Pulinets, Marina Tsidilina, Dimitar Ouzounov, Dmitry Davidenko

Mathematics, Physics, and Computer Science Faculty Articles and Research

The paper provides a comparative analysis of precursory phenomena in the ionosphere and atmosphere for two strong earthquakes of the same magnitude M7.1 that happened in the same region (North-East from Los Angeles) within a time span of 20 years, the Hector Mine and Ridgecrest earthquakes. Regardless of the similarity of their location (South-Eastern California, near 160 km one from another), there was one essential difference: the Hector Mine earthquake happened during geomagnetically disturbed conditions (essential in the sense of ionospheric precursors identification). In contrast, the quiet geomagnetic conditions characterized the period around the time of the Ridgecrest earthquake. The …

T112, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

Pf5, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘PS’ and ‘PF’ spreadsheets are the data of the prediction and calibration tests. (The data in this series are overall stress and strain information).

Supporting information

Dem, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘DEM’ spreadsheet is the simulation results. The test information of the numerical samples is included in it.

Supporting information

Pf Series, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘PS’ and ‘PF’ spreadsheets are the data of the prediction and calibration tests. (The data in this series are overall stress and strain information).

Supporting information

Pf6, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘PS’ and ‘PF’ spreadsheets are the data of the prediction and calibration tests. (The data in this series are overall stress and strain information).

Supporting information

T113, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

T144, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

T514, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

Strain Field_X, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘Strain field_x’ spreadsheet is the radial strain information of all the nodes. The first two columns of data are location information of the node in pixel coordinates. The third column is the information recorded at the first time, the fourth column is the information recorded at the second time, and so on.

Supporting information

T134, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

T154, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

T314, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

T114, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

T414, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

Strain Field_Y, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘Strain field_y’ spreadsheet is the axial strain information of all the nodes. Data format is the same as ‘Strain field_x’

Supporting information

Pf7, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘PS’ and ‘PF’ spreadsheets are the data of the prediction and calibration tests. (The data in this series are overall stress and strain information).

Supporting information

Ps Series, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘PS’ and ‘PF’ spreadsheets are the data of the prediction and calibration tests. (The data in this series are overall stress and strain information).

Supporting information

T111, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

T124, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

T214, Pingxin Xia, Longtan Shao, Wen Deng

Stress-State Dependency of the Deformation Ratio of Quasi-Elastic Granular Soils under Cyclic Loading -- Raw Data

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information).

Supporting information

High-Precision U-Pb Age Constraints On The Permian Floral Turnovers, Paleoclimate Change, And Tectonics Of The North China Block, Qiong Wu, Jahandar Ramezani, Hua Zhang, Jun Wang, Wan Yang, For Full List Of Authors, See Publisher's Website.

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Permian marine-terrestrial system of the North China block provides an exceptional window into the evolution of northern temperate ecosystems during the critical transition from icehouse to greenhouse following the late Paleozoic ice age (LPIA). Despite many studies on its rich hydrocarbon reserves and climate-sensitive fossil flora, uncertain temporal constraints and correlations have hampered a thorough understanding of the records of geologic, biologic, and climatic change from the North China block. We present a new chronostratigraphy based on high-precision U-Pb chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) geochronology of tuffs from a near-complete latest Carboniferous-Permian succession in North China. The …

Diatoms In Hyporheic Sediments Trace Organic Matter Retention And Processing In The Mcmurdo Dry Valleys, Antarctica, Anna J. Bergstrom

Geosciences Faculty Publications and Presentations

In low‐nutrient streams in cold and arid ecosystems, the spiraling of autochthonous particulate organic matter (POM) may provide important nutrient subsidies downstream. Because of its lability and the spatial heterogeneity of processing in hyporheic sediments, the downstream transport and fate of autochthonous POM can be difficult to trace. In Antarctic McMurdo Dry Valley (MDV) streams, any POM retained in the hyporheic zone is expected to be derived from surface microbial mats that contain diatoms with long‐lasting silica frustules. We tested whether diatom frustules can be used to trace the retention of autochthonous POM in the hyporheic zone and whether certain …

Resonant Frequency Derived From The Rayleigh‐Wave Dispersion Image: The High‐Impedance Boundary Problem, Lee M. Liberty, James St. Clair, T. Dylan Mikesell, William D. Schermerhorn

Geosciences Faculty Publications and Presentations

We present a simple and automated approach to estimate primary site‐response resonance, layer thickness, and shear‐wave velocity directly from a dispersion image for a layer over half‐space problem. We demonstrate this for high‐impedance boundary conditions that lie in the upper tens of meters. Our approach eliminates the need for time‐consuming dispersion curve picking and 1D shear‐wave velocity inversion for large data volumes that can capture velocity structure in profile. We highlight important relationships between dispersion characteristics and resonance parameters through synthetic modeling and field data acquired over Atlantic Coastal Plain sediments. In this environment, shallow soil conditions are critical to …