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Geophysics and Seismology Commons™

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2014

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Articles 61 - 90 of 113

Full-Text Articles in Geophysics and Seismology

Session F-4: Modeling An Earthquake In Your Classroom, Brian Grublesky Feb 2014

Session F-4: Modeling An Earthquake In Your Classroom, Brian Grublesky

Professional Learning Day

Teachers will model earthquakes using both technology and hands-on inquiry activities. Teachers will have a chance to engineer an “earthquake proof” building and use the engineering process to test and redesign their buildings before being tested on a shake table. We will also discuss how these activities connect not only to the Next Generation Science Standards, but the Common Core State Standards as well.


Slides: Thoughts On Regulatory Mechanisms For Natural Resource Development: Alternatives To Command And Control, Including A Look At Open Source Approaches, Stanley Dempsey Feb 2014

Slides: Thoughts On Regulatory Mechanisms For Natural Resource Development: Alternatives To Command And Control, Including A Look At Open Source Approaches, Stanley Dempsey

Natural Resource Industries and the Sustainability Challenge (Martz Winter Symposium, February 27-28)

Presenter: Stanley Dempsey, Chairman, Royal Gold

17 slides


Analyst A: Alternatives In Analysis Of The Utexas1 Surface Wave Dataset, Paul Michaels Feb 2014

Analyst A: Alternatives In Analysis Of The Utexas1 Surface Wave Dataset, Paul Michaels

Geosciences Faculty Publications and Presentations

In February of 2011 an earthquake event caused significant damage and loss of life in Christchurch, New Zealand. Such an event serves as motivation for improved foundation design and characterization of the shallow subsurface. In January of 2013, University of Texas engineers acquired surface wave data which has been made available to the ASCE GeoInstitute Geophysical Engineering Committee for a benchmark project. Participants were invited to process and interpret the common data set. This paper reports the results designated as those of "Analyst A". The active vibroseis and sledgehammer data were combined to produce a composite Rayleigh wave dispersion curve. …


Seismic And Geodetic Evidence For Grounding-Line Control Of Whillans Ice Stream Stick-Slip Events, Martin J. Pratt, J. Paul Winberry, Douglas A. Wiens, Sridhar Anandakrishnan, Richard B. Alley Feb 2014

Seismic And Geodetic Evidence For Grounding-Line Control Of Whillans Ice Stream Stick-Slip Events, Martin J. Pratt, J. Paul Winberry, Douglas A. Wiens, Sridhar Anandakrishnan, Richard B. Alley

All Faculty Scholarship for the College of the Sciences

The tidally modulated, stick‐slip events of Whillans Ice Stream in West Antarctica produce seismic energy from three locations near the grounding line. Using ice velocity records obtained by combining time series from colocated broadband seismometers and GPS receivers installed on the ice stream during the 2010–2011 and 2011–2012 austral summers, along with far‐field seismic recordings of elastic waves, we locate regions of high rupture velocity and stress drop. These regions, which are analogous to “asperities” in traditional seismic fault studies, are areas of elevated friction at the base of the ice stream. Slip events consistently initiate at one of two …


Climate- And Eustasy-Driven Cyclicity In Pennsylvanian Fusulinid Assemblages, Donets Basin (Ukraine), Rimma R. Khodjanyazova, Vladimir I. Davydov, Isabel P. Montañez, Mark D. Schmitz Feb 2014

Climate- And Eustasy-Driven Cyclicity In Pennsylvanian Fusulinid Assemblages, Donets Basin (Ukraine), Rimma R. Khodjanyazova, Vladimir I. Davydov, Isabel P. Montañez, Mark D. Schmitz

Geosciences Faculty Publications and Presentations

A model of cyclic recurrence (~ 0.6–1.2 myr) of three fusulinid assemblages in the Middle Pennsylvanian siliciclastic–carbonate succession of the Donets Basin is proposed. Each cycle records progressive turnover of assemblages in shallow marine environments in response to sea-level and regional climate change. A Hemifusulina-assemblage (A), adapted to cooler and reduced salinity seawater records the onset of sea level rise accompanied by humid climatic conditions. Sea level high stand is captured by the Beedeina–Neostaffella–Ozawainella–Taitzehoella (or Beedeina-dominated) assemblage (B), characteristic of relatively deeper-water environments. The B assemblage is successively replaced by the most …


Application Of A Hillslope-Scale Soil Moisture Data Assimilation System To Military Trafficability Assessment, Alejandro N. Flores, Dara Entekhabi, Rafael L. Bras Feb 2014

Application Of A Hillslope-Scale Soil Moisture Data Assimilation System To Military Trafficability Assessment, Alejandro N. Flores, Dara Entekhabi, Rafael L. Bras

Geosciences Faculty Publications and Presentations

Soil moisture is an important environmental variable that impacts military operations and weapons systems. Accurate and timely forecasts of soil moisture at appropriate spatial scales, therefore, are important for mission planning. We present an application of a soil moisture data assimilation system to military trafficability assessment. The data assimilation system combines hillslope-scale (e.g., 10s to 100s of m) estimates of soil moisture from a hydrologic model with synthetic L-band microwave radar observations broadly consistent with the planned NASA Soil Moisture Active–Passive (SMAP) mission. Soil moisture outputs from the data assimilation system are input to a simple index-based model for vehicle …


Assessing Ability To Forecast Geomorphic System Responses To Climate And Land-Use Changes, Jon D. Pelletier, A. Brad Murray, Jennifer L. Pierce Jan 2014

Assessing Ability To Forecast Geomorphic System Responses To Climate And Land-Use Changes, Jon D. Pelletier, A. Brad Murray, Jennifer L. Pierce

Geosciences Faculty Publications and Presentations

As the global community faces the effects of ongoing and future climate and land-use changes (C&LUC), geoscientists are called to action to assess the risks associated with such changes, assist with forecasts of future Earth states, quantify hazards to life, and suggest reasonable adaptation strategies. Earth surface scientists have developed conceptual and mathematical models for how geomorphic systems, including those associated with natural hazards that put trillions of dollars in infrastructure and tens of millions of lives at risk, will respond to and give feedback on C&LUC.


Comparison Of Non-Heating Paleointensity Techniques Using Basalts From Lemptégy Volcano, France And Synthetic Magnetite-Bearing Samples, Geoffrey A. Lerner Jan 2014

Comparison Of Non-Heating Paleointensity Techniques Using Basalts From Lemptégy Volcano, France And Synthetic Magnetite-Bearing Samples, Geoffrey A. Lerner

Dissertations, Master's Theses and Master's Reports - Open

Data of the strength of Earth’s magnetic field (paleointensity) in the geological past are crucial for understanding the geodynamo. Conventional paleointensity determination methods require heating a sample to a high temperature in one or more steps. Consequently, many rocks are unsuitable for these methods due to a heating-induced experimental alteration. Alternative non-heating paleointensity methods are investigated to assess their effectiveness and reliability using both natural samples from Lemptégy Volcano, France, and synthetic samples. Paleointensity was measured from the natural and synthetic samples using the Pseudo-Thellier, ARM, REM, REMc, REM’, and Preisach methods.

For the natural samples, only the Pseudo-Thellier method …


A Surface Displacement Analysis For Volcan Pacaya From October 2001 Through March 2013 By Means Of 3-D Modeling Of Precise Position Gps Data, Brianna R. Hetland Jan 2014

A Surface Displacement Analysis For Volcan Pacaya From October 2001 Through March 2013 By Means Of 3-D Modeling Of Precise Position Gps Data, Brianna R. Hetland

Dissertations, Master's Theses and Master's Reports - Open

Volcán Pacaya is one of three currently active volcanoes in Guatemala. Volcanic activity originates from the local tectonic subduction of the Cocos plate beneath the Caribbean plate along the Pacific Guatemalan coast. Pacaya is characterized by generally strombolian type activity with occasional larger vulcanian type eruptions approximately every ten years. One particularly large eruption occurred on May 27, 2010. Using GPS data collected for approximately 8 years before this eruption and data from an additional three years of collection afterwards, surface movement covering the period of the eruption can be measured and used as a tool to help understand activity …


U-Pb Zircon Age Of The Krásné Loučky Tuffite: The Dating Of Visean Flysch In The Moravo-Silesian Paleozoic Basin (Rhenohercynian Zone, Czech Republic), Jakub Jirásek, Jiří Wlosok, Martin Sivek, Dalibor Matýsek, Mark Schmitz, Ivana Sýkorová, Zdeněk Vašíček Jan 2014

U-Pb Zircon Age Of The Krásné Loučky Tuffite: The Dating Of Visean Flysch In The Moravo-Silesian Paleozoic Basin (Rhenohercynian Zone, Czech Republic), Jakub Jirásek, Jiří Wlosok, Martin Sivek, Dalibor Matýsek, Mark Schmitz, Ivana Sýkorová, Zdeněk Vašíček

Geosciences Faculty Publications and Presentations

The only previous U-Pb zircon date for the the Early Carboniferous flysch sequence of the Moravian-Silesian Paleozoic Basin was published in 1987 from tuffogenic material from Kobylí Quarry at Krásné Loučky near the town of Krnov (Silesia, Czech Republic). The measured age of 319 Ma did not agree with its stratigraphic position, and was used as the basis for a hypothesized block of Late Carboniferous paralic molasse incorporated during a later tectonic event. During a survey of the still-active quarry in 2010, volcaniclastic horizons were identified and sampled. Direct correspondence of the tuff units to those sampled in 1987 cannot …


The 17 May 2012 M4.8 Earthquake Near Timpson, East Texas: An Event Possibly Triggered By Fluid Injection, Cliff Frohlich, William Ellsworth, Wesley A. Brown, Michael Brunt, Jim Luetgert, Tim Macdonald, Steve Walter Jan 2014

The 17 May 2012 M4.8 Earthquake Near Timpson, East Texas: An Event Possibly Triggered By Fluid Injection, Cliff Frohlich, William Ellsworth, Wesley A. Brown, Michael Brunt, Jim Luetgert, Tim Macdonald, Steve Walter

Faculty Publications

This study summarizes our investigation of the 17 May 2012 MW‐RMT4.8 earthquake near Timpson, Texas, the largest earthquake recorded historically in eastern Texas. To identify preshocks and aftershocks of the 17 May event we examined the arrivals recorded at Nacogdoches (NATX) 30 km from the 17 May epicenter, at nearby USArray Transportable Array stations, and at eight temporary stations deployed between 26 May 2012 and mid‐2013. At NATX we identified seven preshocks, the earliest occurring in April 2008. Reliably located aftershocks recorded by the temporary stations lie along a 6 km long NW‐SE linear trend corresponding to a …


Depth To Curie Temperature Across The Central Red Sea From Magnetic Data Using The De-Fractal Method, Ahmed Salem, Chris Green, Dhananjay Ravat, Kumar Hemant Singh, Paul East, J. Derek Fairhead, Saad Mogren, Ed Biegert Jan 2014

Depth To Curie Temperature Across The Central Red Sea From Magnetic Data Using The De-Fractal Method, Ahmed Salem, Chris Green, Dhananjay Ravat, Kumar Hemant Singh, Paul East, J. Derek Fairhead, Saad Mogren, Ed Biegert

Earth and Environmental Sciences Faculty Publications

The central Red Sea rift is considered to be an embryonic ocean. It is characterised by high heat flow, with more than 90% of the heat flow measurements exceeding the world mean and high values extending to the coasts — providing good prospects for geothermal energy resources. In this study, we aim to map the depth to the Curie isotherm (580 °C) in the central Red Sea based on magnetic data. A modified spectral analysis technique, the “de-fractal spec- tral depth method” is developed and used to estimate the top and bottom boundaries of the magnetised layer. We use a …


Precambrian Evolution Of The Salalah Crystalline Basement From Structural Analysis And 40Ar/39Ar Geochronology, Hanadi Abulateef Al-Doukhi Jan 2014

Precambrian Evolution Of The Salalah Crystalline Basement From Structural Analysis And 40Ar/39Ar Geochronology, Hanadi Abulateef Al-Doukhi

Doctoral Dissertations

"The Salalah Crystalline Basement (SCB) is the largest Precambrian exposure in Oman located on the southern margin of the Arabian Plate at the Arabian Sea shore. This work used remote sensing, detailed structural analysis and the analysis of ten samples using 40Ar/39Ar age dating to establish the Precambrian evolution of the SCB by focusing on its central and southwestern parts. This work found that the SCB evolved through four deformational events that shaped its final architecture: (1) Folding and thrusting event that resulted in the emplacement of the Sadh complex atop the Juffa complex. This event resulted …


Crustal Thickness And Vp/Vs Beneath The Western United States: Constraints From Stacking Of Receiver Functions, Uranbaigal Purevsuren Jan 2014

Crustal Thickness And Vp/Vs Beneath The Western United States: Constraints From Stacking Of Receiver Functions, Uranbaigal Purevsuren

Doctoral Dissertations

"This study investigates crustal characteristics beneath the western United States. Crustal parameters, including crustal thickness (H), mean Vp/Vs, and the sharpness of the Moho as quantified by the amplitude of the P-to-S converted phases from the Moho, are measured at a total of 1000 permanent and portable broadband seismic stations using over 150,000 receiver functions recorded between 1988 and 2012. The study area is composed of a diverse set of tectonic provinces formed by a series of tectonic events, and is thus ideal for investigating crustal formation and modification by different tectonic processes. The resulting crustal thickness varies from …


Geothermal Systems Of Northern Thailand And Their Association With Faults Active During The Quaternary, Spencer H. Wood, Fongsaward Suvagondha Singharajwarapan Jan 2014

Geothermal Systems Of Northern Thailand And Their Association With Faults Active During The Quaternary, Spencer H. Wood, Fongsaward Suvagondha Singharajwarapan

Geosciences Faculty Publications and Presentations

Many of northern Thailand hot springs systems are associated with regions of active faulting. An arcuate pattern of wells with high-fluoride water occurs in the Chiang Mai basin. The pattern is parallel to the Mae Tha fault which cuts Paleozoic and Mesozoic rocks 10 km east of the basin. The San Kamphaeng geothermal system is within parallel faults in Paleozoic rocks. The Mae Tha fault is believed to be active in the Quaternary. A conceptual diagram shows deep groundwater circulation driven by ~300 to 800 meters of relief in the hills east of the basin. The Mae Chan geothermal system …


Continuous Snowpack Monitoring Using Upward-Looking Ground-Penetrating Radar Technology, Lino Schmid, Achim Heilig, Christoph Mitterer, Jürg Schweizer, Hansruedi Maurer, Robert Okorn, Olaf Eisen Jan 2014

Continuous Snowpack Monitoring Using Upward-Looking Ground-Penetrating Radar Technology, Lino Schmid, Achim Heilig, Christoph Mitterer, Jürg Schweizer, Hansruedi Maurer, Robert Okorn, Olaf Eisen

Geosciences Faculty Publications and Presentations

Snow stratigraphy and water percolation are key contributing factors to avalanche formation. So far, only destructive methods can provide this kind of information. Radar technology allows continuous, non-destructive scanning of the snowpack so that the temporal evolution of internal properties can be followed. We installed an upward-looking ground-penetrating radar system (upGPR) at the Weissfluhjoch study site (Davos, Switzerland). During two winter seasons (2010/11 and 2011/12) we recorded data with the aim of quantitatively determining snowpack properties and their temporal evolution. We automatically derived the snow height with an accuracy of about ±5 cm, tracked the settlement of internal layers (±7 …


Science And Public Policy Of Earthquake Hazard Mitigation In The New Madrid Seismic Zone, Alice M. Orton Jan 2014

Science And Public Policy Of Earthquake Hazard Mitigation In The New Madrid Seismic Zone, Alice M. Orton

Theses and Dissertations--Earth and Environmental Sciences

In the central United States, undefined earthquake sources, long earthquake recurrence intervals and uncertain ground motion attenuation models have contributed to an overstatement of regional seismic hazard for the New Madrid Seismic Zone on the National Seismic Hazard Maps. This study examined concerns regarding scientific uncertainties, overly stringent seismic mitigation policies and depressed local economy in western Kentucky through a series of informal interviews with local businessmen, public officials, and other professionals in occupations associated with seismic mitigation. Scientific and relative economic analyses were then performed using scenario earthquake models developed with FEMA’s Hazus-MH software. Effects of the 2008 Wenchuan …


Why Ricker Wavelets Are Successful In Processing Seismic Data: Towards A Theoretical Explanation, Afshin Gholamy Salehabady Jan 2014

Why Ricker Wavelets Are Successful In Processing Seismic Data: Towards A Theoretical Explanation, Afshin Gholamy Salehabady

Open Access Theses & Dissertations

In many engineering applications ranging from engineering seismology to petroleum engineering and civil engineering, processing seismic data plays a key role. In processing seismic data, it turns out to be very efficient to describe the signal's spectrum as a linear combination of Ricker wavelet spectra.

In this Thesis, we provide a possible theoretical explanation for this empirical efficiency. Specifically, signal propagation through several layers is discussed, and it is shown that the Ricker wavelet is the simplest non-trivial solution for the corresponding data processing problem, under the condition that the described properties of the approximation family are satisfied.


Investigating The Anisotropy Of Magnetic Susceptibility And Other Rock Magnetic Properties Of The Beaver River Diabase In Northeastern Minnesota, Samer H. Hariri Jan 2014

Investigating The Anisotropy Of Magnetic Susceptibility And Other Rock Magnetic Properties Of The Beaver River Diabase In Northeastern Minnesota, Samer H. Hariri

Wayne State University Theses

The Beaver River Diabase (BRD) is a series of mafic dikes and sills within the Beaver Bay Complex (BBC) of northern Minnesota, which formed during the development of the ~1.1 Ga Midcontinent Rift (MCR). The BRD is one of the youngest and most extensive intrusive phases of the BBC. The BRD dikes and sills were emplaced into the medial levels of the 6-10 kilometer-thick North Shore Volcanic Group and occur over an arcuate area extending 120 by 20 kilometers. The BRD is composed of fine- to medium-grained ophitic olivine gabbro and does not display obvious foliation or lineation features and …


Using Time-Lapse Three Dimensional Vertical Seismic Profiling To Monitor Injected Fluids During Geologic Carbon Sequestration, John B. Hickman Jan 2014

Using Time-Lapse Three Dimensional Vertical Seismic Profiling To Monitor Injected Fluids During Geologic Carbon Sequestration, John B. Hickman

Report of Investigations--KGS

Two three-dimensional vertical seismic profiles (3D-VSP) were acquired at the KGS Marvin Blan No. 1 CO2 sequestration research well outside of Cloverport in Hancock County, Ky. The initial (preinjection) survey was performed September 15-16, 2010, and was followed by the injection of 361.2 metric tons of supercritical CO2 and then 584 m3 of 2 percent potassium chloride water (to displace the remaining CO2 in the wellbore) on September 22, 2010. After injection, the well was shut in with a downhole pressure of 17.5 MPa at the injected reservoir depth of 1,545.3 m. A second 3D-VSP was …


Brownfield Action: Dissemination Of A Sencer Model Curriculum And The Creation Of A Collaborative Stem Education Network, Peter Bower, Ryan Kelsey, Joseph Liddicoat, Doug M. Thompson, Angelo Lampousis, Bret Bennington, Bess Greenbaum Seewald, Arthur D. Kney, Saugata Datta, Lawrence D. Lemke, Briane Sorice Miccio, Tamara Graham Jan 2014

Brownfield Action: Dissemination Of A Sencer Model Curriculum And The Creation Of A Collaborative Stem Education Network, Peter Bower, Ryan Kelsey, Joseph Liddicoat, Doug M. Thompson, Angelo Lampousis, Bret Bennington, Bess Greenbaum Seewald, Arthur D. Kney, Saugata Datta, Lawrence D. Lemke, Briane Sorice Miccio, Tamara Graham

Publications and Research

Brownfield Action (BA) is a web-based environmental site assessment (ESA) simulation in which students form geotechnical consulting companies and work together to solve problems in environmental forensics. Developed at Barnard College with the Columbia Center for New Media Teaching and Learning, BA has been disseminated to ten colleges, universities, and high schools, resulting in a collaborative network of educators. The experiences of current users are presented describing how they have incorporated the BA curriculum into their courses, as well as how BA affected teaching and learning. The experiences demonstrate that BA can be used in whole or in part, is …


Instrument Correction And Dynamic Site Profile Validation At The Central United States Seismic Observatory, New Madrid Seismic Zone, Clayton M.J. Brengman Jan 2014

Instrument Correction And Dynamic Site Profile Validation At The Central United States Seismic Observatory, New Madrid Seismic Zone, Clayton M.J. Brengman

Theses and Dissertations--Earth and Environmental Sciences

The Central United States Seismic Observatory (CUSSO), is a fifteen-element array of three-component accelerometers and seismometers in the New Madrid seismic zone, within the upper Mississippi embayment. Its location within the thick (up to 1 km) sequences of unlithified sediment comprising the embayment, make CUSSO a unique array in its ability to directly measure seismic wave propagation, including ground motion site effect; however, before the observational data can be used for analysis, the orientation and instrument response of the CUSSO array must be defined. This study used cross-correlation and direct comparisons to filter out the instrument response and determine the …


Application Of The Kalman Filter On Full Tensor Gravity Gradiometry Data Around The Vinton Salt Dome, Louisiana, Mahnaz Sepehrmanesh Jan 2014

Application Of The Kalman Filter On Full Tensor Gravity Gradiometry Data Around The Vinton Salt Dome, Louisiana, Mahnaz Sepehrmanesh

Theses and Dissertations--Earth and Environmental Sciences

Full tensor gravity (FTG) data are known for their high resolution but also for higher noise in its components due to the dynamic nature of the platform used for data acquisition. Although a review of the literature suggests steady increase in the success of gravity gradiometry, we still cannot take advantage of the full potential of the method, mostly because of the noise with the same amplitude and wavenumber characteristics as the signal that affects these data. Smoothing from common low pass filters removes small wavelength features and makes it difficult to detect structural features and other density variations of …


Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu Jan 2014

Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu

Department of Earth, Environment and Sustainability Faculty Publications

Reconstruction of the Hirnantian (Late Ordovician) palaeotopography in South China is important for understanding the distribution pattern of the Hirnantian marine depositional environment. In this study, we reconstructed the Hirnantian palaeotopography in the Upper Yangtze region based on the rankings of the palaeo-water depths, which were inferred according to the lithofacies and biofacies characteristics of the sections. Data from 374 Hirnantian sections were collected and standardized through the online Geobiodiversity Database. The Ordinary Kriging interpolation method in the ArcGIS software was applied to create the continuous surface of the palaeo-water depths, i.e. the Hirnantian palaeotopography. Meanwhile, the line transect analysis …


Geodesy- And Geology-Based Slip-Rate Models For The Western United States (Excluding California) National Seismic Hazard Maps, Mark D. Petersen, Yuehua Zeng, Kathleen M. Haller, Robert Mccaffrey, William C. Hammond, Peter Bird, Morgan Moschetti, Zheng-Kang Shen, Jayne Bormann, Wayne R. Thatcher Jan 2014

Geodesy- And Geology-Based Slip-Rate Models For The Western United States (Excluding California) National Seismic Hazard Maps, Mark D. Petersen, Yuehua Zeng, Kathleen M. Haller, Robert Mccaffrey, William C. Hammond, Peter Bird, Morgan Moschetti, Zheng-Kang Shen, Jayne Bormann, Wayne R. Thatcher

Geology Faculty Publications and Presentations

The 2014 National Seismic Hazard Maps for the conterminous United States incorporate additional uncertainty in fault slip-rate parameter that controls the earthquake-activity rates than was applied in previous versions of the hazard maps. This additional uncertainty is accounted for by new geodesy- and geology-based slip-rate models for the Western United States. Models that were considered include an updated geologic model based on expert opinion and four combined inversion models informed by both geologic and geodetic input. The two block models considered indicate significantly higher slip rates than the expert opinion and the two fault-based combined inversion models. For the hazard …


Tidal Pacing, Skipped Slips And The Slowdown Of Whillans Ice Stream, Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley, Douglas A. Wiens, Martin J. Pratt Jan 2014

Tidal Pacing, Skipped Slips And The Slowdown Of Whillans Ice Stream, Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley, Douglas A. Wiens, Martin J. Pratt

All Faculty Scholarship for the College of the Sciences

We summarize new observations of the deceleration and stick–slip motion of Whillans Ice Stream (WIS), Antarctica. We refine the location of the large sticky spots that resist motion between slip events, the locations of which are controlled by the patterns of subglacial water flow. Our examination of the long-term velocity time series for the ice stream reveals that the decadal-scale deceleration is not occurring at a steady rate, but varies at the sub-decadal timescale. This unsteady deceleration modulates the temporal evolution of a broad (~50 km across) surface-elevation bulge forming at the junction between the relatively narrow upstream portion of …


Large-Scale Fluidization Features From Late Holocene Coseismic Paleoliquefaction In The Willamette River Forearc Valley, Central Cascadia Subduction Zone, Oregon, Usa, Curt D. Peterson, Kurt Kristensen, Rick Minor Jan 2014

Large-Scale Fluidization Features From Late Holocene Coseismic Paleoliquefaction In The Willamette River Forearc Valley, Central Cascadia Subduction Zone, Oregon, Usa, Curt D. Peterson, Kurt Kristensen, Rick Minor

Geology Faculty Publications and Presentations

A search of Willamette River cutbanks was conducted for the presence of late Holocene paleoli-quefaction records in the Willamette forearc valley, located 175 ± 25 km landward from the buried trench in the central Cascadia subduction zone. A search of Willamette River cutbanks was conducted for the presence of late Holocene paleoli-quefaction records in the Willamette forearc valley, located 175 ± 25 km landward from the buried trench in the central Cascadia subduction zone. Eight cutbank sites are reported that show evidence of large-scale fluidization features (≥10 cm width) including clastic sand dikes and intruded sand sills in Holocene overbank …


Analyzing Stress Drops Of Earthquakes Near Wellington, New Zealand, Kyle Eugene Barnes Jan 2014

Analyzing Stress Drops Of Earthquakes Near Wellington, New Zealand, Kyle Eugene Barnes

Open Access Theses & Dissertations

Stress drop studies analyze the change of stress across faults before and after an earthquake. The goal of this study was to determine how stress drop varies throughout the Wellington region of the North Island of New Zealand. To the east of the North Island, the Hikurangi Trough obliquely subducts the Pacific Plate beneath the younger Australian Plate. Toward the southern end of the North Island and into Cook Strait the Pacific plate becomes more buoyant and the plate interface displays strong coupling as subduction diminishes into the strike-slip Marlborough fault system. Subduction of the Pacific plate ceases beneath the …


Thermobarometry And Geochronology In The Dulan Region, North Qaidam Ultrahigh-Pressure Terrane: Resolving Spatial Variation Of Ages, Temperatures, And Pressures, Megan Eileen Regel Jan 2014

Thermobarometry And Geochronology In The Dulan Region, North Qaidam Ultrahigh-Pressure Terrane: Resolving Spatial Variation Of Ages, Temperatures, And Pressures, Megan Eileen Regel

All Master's Theses

The Dulan ultrahigh-pressure (UHP) terrane exposes 449-422 Ma eclogites in the east and 449-418 Ma high-pressure granulites to the west, but the relationship between the units is poorly understood. Zirconium-in-rutile temperatures show an east-west 3- 5°C/km gradient in four UHP eclogites: 662-716±10°C; garnet-omphacite-phengite thermobarometry of peak conditions yields 659-730±82°C, 25.3-27.1±3.2 kbars. Zircon U-Pb ages of four eclogites are the same within uncertainty, averaging 434±2.9 Ma. Tiin- zircon thermometry and rare earth element patterns indicate these ages represent eclogite facies metamorphism. One high-pressure/high-temperature (HP/HT) granulite yields a minimum rutile temperature of 773±4°C. Previous thermobarometry of highpressure granulites yields ≥800°C and 14-17 …


Spatial Relationship Between Gps Slip And Seismic Tremor During Cascadia Slow Slip Events, Hillary Lynn Goodner Jan 2014

Spatial Relationship Between Gps Slip And Seismic Tremor During Cascadia Slow Slip Events, Hillary Lynn Goodner

All Master's Theses

We model GPS deformation and timing of seismic tremor associated with transient deformation in Cascadia to test the hypothesis that tremor and slip occur synchronously but are spatially offset. For the period 2010–2013, we use seismic tremor data with a duration-moment relationship to predict GPS time series and compare them to observations. We find that observed GPS displacements are best predicted when tremor locations on the plate interface are shifted 15 km up-dip of their published epicenter. To test whether the spatial offset of tremor and slip is due to systematic mislocation of published epicenters, we attempt to identify individual …