Open Access. Powered by Scholars. Published by Universities.®

Geophysics and Seismology Commons

Open Access. Powered by Scholars. Published by Universities.®

1,647 Full-Text Articles 2,318 Authors 261,699 Downloads 83 Institutions

All Articles in Geophysics and Seismology

Faceted Search

1,647 full-text articles. Page 1 of 43.

Seismic Imaging Of The Main Frontal Thrust In Nepal Reveals A Shallow Décollement And Blind Thrusting, Rafael V. Almeida, Judith Hubbard, Lee Liberty, Anna Foster, Soma Nath Sapkota 2018 Nanyang Technological University

Seismic Imaging Of The Main Frontal Thrust In Nepal Reveals A Shallow Décollement And Blind Thrusting, Rafael V. Almeida, Judith Hubbard, Lee Liberty, Anna Foster, Soma Nath Sapkota

CGISS Publications and Presentations

Because great earthquakes in the Himalaya have an average recurrence interval exceeding 500 yr, most of what we know about past earthquakes comes from paleoseismology and tectonic geomorphology studies of the youngest fault system there, the Main Frontal Thrust (MFT). However, these data are sparse relative to fault segmentation and length, and interpretations are often hard to validate in the absence of information about fault geometry. Here, we image the upper two km of strata in the vicinity of the fault tip of the MFT in central Nepal (around the town of Bardibas) applying a pre-stack migration approach to two ...


Joint Geodetic And Seismic Analysis Of Englacial And Subglacial Hydraulic Effects On Surface Crevassing Near A Seasonal, Glacier-Dammed Lake On Gornergletscher, Switzerland, Louis Stephen Garcia 2018 Louisiana State University and Agricultural and Mechanical College

Joint Geodetic And Seismic Analysis Of Englacial And Subglacial Hydraulic Effects On Surface Crevassing Near A Seasonal, Glacier-Dammed Lake On Gornergletscher, Switzerland, Louis Stephen Garcia

LSU Master's Theses

Glacial outburst floods are difficult to predict and threaten human life. These events are characterized by rapid draining of glacier-dammed lakes via the sub/englacial hydraulic network to the proglacial stream. The glacier-dammed lake on Gornergletscher in Switzerland, which fills and drains each summer, provides an opportunity to study this hazard. For three drainages (2004, 2006, and 2007), icequakes (IQ) are tracked as well as on-ice GPS movement. The seasonal seismic networks had 8 – 24 three-component stations and apertures of about 300 – 400 m on the glacier surface. The seasonal GPS arrays contained 4 – 8 GPS antennae on the glacier ...


Characterization Of Ground Deformation Associated With Shallow Groundwater Processes Using Satellite Radar Interferometry, Xie Hu 2018 Southern Methodist University

Characterization Of Ground Deformation Associated With Shallow Groundwater Processes Using Satellite Radar Interferometry, Xie Hu

Earth Sciences Theses and Dissertations

Shallow groundwater processes maylead to ground deformation and even geohazards. With the features of day-and-night accessibility and large-scale coverage, time-series interferometric synthetic aperture radar (InSAR) has proven a useful tool for mapping the deformation over various landscapes at cm to mm level with weekly to monthly updates. However, it has limitations such as, decorrelation,atmospheric artifacts, topographic errors, andunwrapping errors, in particular for the hilly, vegetated, and complicated deformation patterns. In this dissertation, I focus on characterizing the ground deformation over landslides, aquifer systems, and mine tailings impoundment, using the designed advanced time-series InSAR strategy, as well as theinterdisciplinary knowledge ...


Determining Principal Stress Orientations And Magnitudes In The Fort Worth Basin, Texas, Louis Quinones 2018 Southern Methodist University

Determining Principal Stress Orientations And Magnitudes In The Fort Worth Basin, Texas, Louis Quinones

Earth Sciences Theses and Dissertations

Since 2008, the Fort Worth Basin in northern Texas has experienced over 30 M3.0+ earthquakes, including one M4.0. Earthquakes have primarily occurred on Precambrian basement faults and within the overlying Ellenburger limestone unit, which is the primary wastewater disposal formation used in the basin. The most productive earthquake sequences (Azle, Irving- Dallas, and Venus) have been recorded using local seismic networks containing a mix of SMU broadband, IRIS short period, and USGS NetQuakes stations and by regional seismic networks operated under the Advanced National Seismic System and the Texas Seismic Network (TexNet).

Using the data recorded by the ...


A Geophysical Delineation Of A Normal Fault Within The Gulf Coastal Plain, Montgomery County, Texas, Danielle Minteer 2018 Stephen F. Austin State University

A Geophysical Delineation Of A Normal Fault Within The Gulf Coastal Plain, Montgomery County, Texas, Danielle Minteer

Electronic Theses and Dissertations

The Gulf Coast of Texas has been a known hydrocarbon basin for many years with various structural trapping mechanisms such as anticlines, faults and salt domes. While most large salt domes have been extensively studied in the Gulf Coastal Plain, many smaller normal faults have not been studied in detail. This research study employs an integrated geophysical approach to mapping the Big Barn fault in Montgomery County, Texas. This fault is located on the Gulf Coastal Plain and is approximately 20 miles north of Houston, Texas. Most normal faults in the Gulf Coastal Plain formed as a result of the ...


Estimation Of Porosity And Water Saturation In Dual-Porosity Pyroclastic Deposits From Joint Analysis Of Compression, Shear, And Electromagnetic Velocities, Andrew C. Gase, John H. Bradford, Brittany D. Brand 2018 University of Texas at Austin

Estimation Of Porosity And Water Saturation In Dual-Porosity Pyroclastic Deposits From Joint Analysis Of Compression, Shear, And Electromagnetic Velocities, Andrew C. Gase, John H. Bradford, Brittany D. Brand

Geosciences Faculty Publications and Presentations

In situ measurements of porosity and water saturation of pyroclastic deposits have the potential to improve interpretations of geology and hydrology in volcanic regions, and to provide more accurate estimates of dense rock equivalent for volcanic eruptions. However, rock-property models must consider the dual-porosity structure of pyroclastic deposits (i.e., vesicles within pumices and intergranular pores). Vesicularity, intergranular porosity, and water saturation all affect the density, elasticity, and dielectric properties of pyroclastic materials, which control seismic and electromagnetic velocities. The data from active seismic and ground-penetrating radar (GPR) techniques may improve porosity and water saturation estimation if the responses of ...


Multi-Channel Ground-Penetrating Radar For The Continuous Quantification Of Snow And Firn Density, Depth, And Accumulation, Tate Meehan 2018 Boise State University

Multi-Channel Ground-Penetrating Radar For The Continuous Quantification Of Snow And Firn Density, Depth, And Accumulation, Tate Meehan

Boise State University Theses and Dissertations

A priority of ice sheet surface mass balance (SMB) prediction is ascertaining the surface density and annual snow accumulation. These forcing data are inputs for firn density models and can be used to inform remotely sensed ice sheet surface processes and to assess Regional Climate Model (RCM) skill. The Greenland Traverse for Accumulation and Climate Studies (GreenTrACS) retrieved 16 shallow firn cores and dug 42 snow pits along the Western percolation zone of the Greenland Ice Sheet (GrIS) during May and June of 2016 and 2017. I deployed and maintained a multi-channel 500 MHz ground-penetrating radar in a multi-offset configuration ...


Liquefaction-Induced Dragload And/Or Downdrag On Deep Foundations Within The New Madrid Seismic Zone, Ishimwe Elvis 2018 University of Arkansas, Fayetteville

Liquefaction-Induced Dragload And/Or Downdrag On Deep Foundations Within The New Madrid Seismic Zone, Ishimwe Elvis

Theses and Dissertations

Deep foundation elements are typically used to transfer structural loads for multi-story buildings and large-span bridges to a competent soil layer when 1) the soil close to the ground surface has no sufficient bearing capacity, and when 2) liquefiable soils are encountered. The majority of the bridges constructed within seismic zones rely upon the stability of earthen embankments and deep foundation that are installed above or within liquefiable soil deposits. Despite large factor of safety values or different load and resistance factors being used to adequately design deep foundations within seismic areas, soil liquefaction may cause extensive damage to the ...


Interpretation And Fracture Characterization Of Early-Cretaceous Buda Limestone Formation Using Post-Stack 3d Seismic Data In Zavala County, Texas, Andrey Smirnov 2018 University of Arkansas, Fayetteville

Interpretation And Fracture Characterization Of Early-Cretaceous Buda Limestone Formation Using Post-Stack 3d Seismic Data In Zavala County, Texas, Andrey Smirnov

Theses and Dissertations

The Buda Limestone is a naturally fractured Early Cretaceous carbonate formation in south Texas which unconformably underlies the Eagle Ford Shale. Matrix porosity of the Buda is less than 6%, therefore natural fractures improve the potential for commercial hydrocarbon production from this tight limestone formation. This presents a challenge for producers to identify these zones using well log and post stack 3D seismic data typically available to medium or small exploration companies. This project provides a workflow based on well log analysis tied to seismic acoustic impedance (AI) inversion to locate areas of probable natural fractures. Acoustic impedance inversion was ...


Seismology And Volcanology: Exploration Of Volcanoes, Long-Periods, And Machines - Predicting Volcano Eruption Using Signature Seismic Data, Kyle Killion, Rajeev Kumar, Celia J. Taylor, Gabriele Morra 2018 Southern Methodist University

Seismology And Volcanology: Exploration Of Volcanoes, Long-Periods, And Machines - Predicting Volcano Eruption Using Signature Seismic Data, Kyle Killion, Rajeev Kumar, Celia J. Taylor, Gabriele Morra

SMU Data Science Review

Abstract. Seismo-volcanologists manually isolate and verify long-period waves and Strombolian events using seismic and acoustic waves. This is a very detailed and time-consuming process. This project is to employ machine learning algorithms to find models which locate long-period and Strombolian signatures automatically. By comparing the timing of seismic and acoustic waves, clustering techniques effectively isolated big volcanic events and aided in the further refinement of techniques to capture the hundreds of typical daily Strombolian events at Villarrica volcano. Within the research, we utilized the unsupervised machine learning environment to locate a group of signatures for customizing machine learned long-period signature ...


Regional Stress Regime Study Of East Texas Based On Orientation Of Fractures In The Weches Formation, Cory D. Ellison 2018 Stephen F Austin State University

Regional Stress Regime Study Of East Texas Based On Orientation Of Fractures In The Weches Formation, Cory D. Ellison

Electronic Theses and Dissertations

Fractures in the Weches Formation in a roughly 50 mile radius around Nacogdoches, Texas were documented and analyzed using data obtained at various outcrops. This data was used to infer information about the regional stress regime based on the direction of maximum/minimum horizontal stresses (SHmax / SHmin) that formed the fractures. This is based on the principle that systematic, steeply dipping, mode I joints propagate in the direction of SHmax and normal to the direction of SHmin. Joints in the Weches Formation are typically iron filled and are predominantly opening mode, indicated by crack-seal formation, steep dip (700 – 900) and ...


Investigation On Relationships Between Optical Properties And Cell Concentrations Of Microalgae, Zhaoming Zhou 2018 Montana Tech

Investigation On Relationships Between Optical Properties And Cell Concentrations Of Microalgae, Zhaoming Zhou

Graduate Theses & Non-Theses

Biofuel from microalgae is a very promising renewable energy resource. Growth of microalgae depends on ambient temperature, appropriate nutrients in water, and light condition for photosynthesis. As microalgae grow, the depth of light penetration decreases and the growing conditions at depth deteriorate. Monitoring of microalgae concentration during their growing phase is imperative to ensure efficiency in biomass production. Conventionally, cell concentration (number of cells per unit volume) of microalgae solution is estimated by taking images of samples under microscope and then counted and estimated using the Metallized Hemacytometer Hausser Bright-Linewe (MHHBL) method developed by Hausser Scientific. This method of measuring ...


Assessment Of Ground-Based And Aerial Cloud Seeding Using Trace Chemistry, James M. Fisher, Marion L. Lytle, Shawn G. Benner 2018 Boise State University

Assessment Of Ground-Based And Aerial Cloud Seeding Using Trace Chemistry, James M. Fisher, Marion L. Lytle, Shawn G. Benner

Shawn G. Benner

Targeting seedable clouds with silver iodide in complex terrain adds considerable uncertainty in weather modification studies. This study explores the geographic and temporal distribution of silver iodide associated with an active cloud seeding program in central Idaho snowpack using trace chemistry. Over 4,000 snow samples were analyzed for the presence of a cloud seeding silver iodide (AgI) signature over two winter seasons. The results indicate the following. (1) At sites within 70 km of AgI sources, silver enrichments were detected at 88% of cases involving seeding efforts from ground generators, but none from aircraft seeded cases. (2) Real-time snow ...


Muang Rae Geothermal System: Drilling And Borehole Geophysics, 1000-M Core Hole Into Granitic Rock, Amphoe Pai, Mae Hong Son Province, Northern Thailand, Spencer H. Wood, Kriangsak Pirarai, Aranya Fuangswasdi, Wiboon Kaentao, Albert Waibel, Fongsaward S. Singharajwarapan 2018 Boise State University

Muang Rae Geothermal System: Drilling And Borehole Geophysics, 1000-M Core Hole Into Granitic Rock, Amphoe Pai, Mae Hong Son Province, Northern Thailand, Spencer H. Wood, Kriangsak Pirarai, Aranya Fuangswasdi, Wiboon Kaentao, Albert Waibel, Fongsaward S. Singharajwarapan

Spencer H. Wood

In 2015, a 1-km core hole was drilled into granitic rock at the Muang Rae geothermal area. Previous drilling in 1993 to 200 m was unsuccessful in obtaining flows, but one of the “dry” wells began flowing in August, 2013 at 9.75 L/s of 96.9°C water from a fracture zone 80 m deep. In the sandy bed of the Pai River, 150 m south of that well is a 600-m long line of hot seeps, oriented NE, with highest temperature measured at 94.5°C. Geology is foliated Triassic (?) granitic rock cut by a NE-SW-trending normal ...


Acoustic And Seismic Fields Of Hydraulic Jumps At Varying Froude Numbers, Timothy J. Ronan, Jonathan M. Lees, T. Dylan Mikesell, Jacob F. Anderson, Jeffrey B. Johnson 2018 University of North Carolina at Chapel Hill

Acoustic And Seismic Fields Of Hydraulic Jumps At Varying Froude Numbers, Timothy J. Ronan, Jonathan M. Lees, T. Dylan Mikesell, Jacob F. Anderson, Jeffrey B. Johnson

T. Dylan Mikesell

Mechanisms that produce seismic and acoustic wavefields near rivers are poorly understood because of a lack of observations relating temporally dependent river conditions to the near-river seismoacoustic fields. This controlled study at the Harry W. Morrison Dam (HWMD) on the Boise River, Idaho, explores how temporal variation in fluvial systems affects surrounding acoustic and seismic fields. Adjusting the configuration of the HWMD changed the river bathymetry and therefore the form of the standing wave below the dam. The HWMD was adjusted to generate four distinct wave regimes that were parameterized through their dimensionless Froude numbers (Fr) and observations of ...


Caves As Observatories For Atmospheric Thermal Tides: An Example From Ascunsă Cave, Romania, Virgil Drăgușin, Laura Tîrlă, Nicoleta Cadicheanu, Vasile Ersek, Ionuț Mirea 2018 Emil Racoviță Institute of Speleology

Caves As Observatories For Atmospheric Thermal Tides: An Example From Ascunsă Cave, Romania, Virgil Drăgușin, Laura Tîrlă, Nicoleta Cadicheanu, Vasile Ersek, Ionuț Mirea

International Journal of Speleology

As part of a microclimate study at Ascunsă Cave, Romania, we used Gemini Tinytag Plus 2 data loggers to record cave air temperature variability. At one of the monitoring points we recognized the presence of semidiurnal cycles on the order of a few thousands of a degree Celsius that could be produced under the influence of the semidiurnal tidal components of the Sun (S2) or the Moon (M2). Using a Gemini Tinytag Plus 2 data logger with an external probe we measured core rock temperature and showed that it does not influence the cave air temperature on such ...


Geologic Framework Of The Fang Hot Springs Area With Emphasis On Structure, Hydrology, And Geothermal Development, Chiang Mai Provence, Northern Thailand, Spencer H. Wood, Pichet Kaewsomwang, Fongsaward Suvagondha Singharajwarapan 2018 Boise State University

Geologic Framework Of The Fang Hot Springs Area With Emphasis On Structure, Hydrology, And Geothermal Development, Chiang Mai Provence, Northern Thailand, Spencer H. Wood, Pichet Kaewsomwang, Fongsaward Suvagondha Singharajwarapan

Geosciences Faculty Publications and Presentations

Geologic mapping, a magnetotelluric survey, well data, and earlier reports are integrated to guide further development of the Fang geothermal system. The Fang Hot Springs originally flowed ~ 20 l s−1 of 90–99 °C water from a 10-hectare area of crystal- line rocks presumed to be of Triassic age. Four wells 92–500 m deep now flow ~ 20 l s−1 of 110–115 °C water and generate 115–250 kWe from the 1989 Ormat binary power plant. Wells are not pumped nor is the spent water re-injected. Temperatures of 130 °C occur in some wells and water chemistry ...


How To Monitor Possible Side Effects Of Enhanced Oil Recovery Process, Jose Manuel Dominguez Esquivel, Solymar Ayala Cortez, Aaron A. Velasco, Vladik Kreinovich 2018 Mexican Petroleum Institute

How To Monitor Possible Side Effects Of Enhanced Oil Recovery Process, Jose Manuel Dominguez Esquivel, Solymar Ayala Cortez, Aaron A. Velasco, Vladik Kreinovich

Departmental Technical Reports (CS)

To extract all the oil from a well, petroleum engineers pump hot reactive chemicals into the well. This enhanced oil recovery process needs to be thoroughly monitored, since the aggressively hot liquid can seep out and, if unchecked, eventually pollute the sources of drinking water. At present, to monitor this process, engineers measure the seismic waves generated when the liquid fractures the minerals. However, the resulting seismic waves are weak in comparison with the background noise. Thus, the accuracy with which we can locate the spreading liquid based on these weak signals is low, and we get only a very ...


One Diamictite And Two Rifts: Stratigraphy And Geochronology Of The Gataga Mountain Of Northern British Columbia, Athena Eyster, Filippo Ferri, Mark D. Schmitz, Francis A. Macdonald 2018 Harvard University

One Diamictite And Two Rifts: Stratigraphy And Geochronology Of The Gataga Mountain Of Northern British Columbia, Athena Eyster, Filippo Ferri, Mark D. Schmitz, Francis A. Macdonald

Geosciences Faculty Publications and Presentations

Neoproterozoic glacial diamictites and rift-related volcanics are preserved throughout the North American Cordillera, yet the nature and timing of both glaciation and rifting are poorly constrained. New geochronological, geochemical, and stratigraphic data from the Cryogenian Gataga volcanics and bounding units at Gataga Mountain, in the Kechika Trough of northern British Columbia, better constrain the age of these rift-related volcanics and suggest that they erupted during glaciation. At Gataga Mountain, three informal sequences are exposed; a basal quartzite, the Gataga volcanics, and an overlying mixed carbonate-siliciclastic succession. The basal quartzite is dominated by cross-bedded sandstone with an intertidal facies assemblage including ...


Evidence Of The 1762 Arakan And Prior Earthquakes In The Northern Sunda Subduction, Dhiman Ranjan Mondal 2018 The Graduate Center, City University of New York

Evidence Of The 1762 Arakan And Prior Earthquakes In The Northern Sunda Subduction, Dhiman Ranjan Mondal

All Dissertations, Theses, and Capstone Projects

The objective of this dissertation is to understand the seismic hazard associated with Arakan segment of the northern Sunda subduction along SE Bangladesh. In order to do that, it is necessary to document geologic evidence for the 1762 Arakan earthquake and prior events, to help estimate the recurrence interval (repeat time) for that earthquake. Historical records described that the 1762 earthquake caused extensive damage along the Arakan segment of the Sunda subduction system. But the geologic evidence for the earthquake farther north is necessary to better understand its associated seismic hazard to the densely populated nation of Bangladesh. This dissertation ...


Digital Commons powered by bepress