Geophysics and Seismology Commons^™

Sequential Fragmentation / Transport Theory, Pyroclast Size-Density Relationships, And The Emplacement Dynamics Of Pyroclastic Density Currents – A Case Study On The Mt. St. Helens (Usa) 1980 Eruption, Chelsea Mackaman-Lofland, Brittany D. Brand, Jacopo Taddeucci, Kenneth Wohletz

Geosciences Faculty Publications and Presentations

Pyroclastic density currents (PDCs) are the most dangerous hazard associated with explosive volcanic eruptions. Despite recent advancements in the general understanding of PDC dynamics, limited direct observation and/or outcrop scarcity often hinder the interpretation of specific transport and depositional processes at many volcanoes. This study explores the potential of sequential fragmentation / transport theory (SFT; cf. Wohletz et al. 1989), a modeling method capable of predicting particle mass distributions based on the physical principles of fragmentation and transport, to retrieve the transport and depositional dynamics of well-characterized PDCs from the size and density distributions of individual components within the deposits. …

On The Amount Of Sediment Deposited In Floodplains From The Mississippi River: A Case Study In Cat Island National Wildlife Refuge, Louisiana, Matthew Smith

Honors Capstones

No abstract provided.

Lunar Cold Spots: Granular Flow Features And Extensive Insulating Materials Surrounding Young Craters, Joshua L. Bandfield, Eugenie Song, Paul O. Hayne, Brittany D. Brand, Rebecca R. Ghent, Ashwin R. Vasavada, David A. Paige

Geosciences Faculty Publications and Presentations

Systematic temperature mapping and high resolution images reveal a previously unrecognized class of small, fresh lunar craters. These craters are distinguished by near-crater deposits with evidence for lateral, ground-hugging transport. More distal, highly insulating surfaces surround these craters and do not show evidence of either significant deposition of new material or erosion of the substrate. The near-crater deposits can be explained by a laterally propagating granular flow created by impact in the lunar vacuum environment. Further from the source crater, at distances of ~10-100 crater radii, the upper few to 10s of centimeters of regolith appear to have been “fluffed-up” …

Detection Of An Ultra Low Velocity Zone Beneath Central Mexico With Pcp Waveform Modeling, David James Buckley

Physics

PcP phases from a Guatemalan earthquake recorded at Nevada stations of the International seismic network (IM) display evidence of anomalous seismic structure at the core-mantle boundary (CMB); in particular, pre- and post-cursor phases to PcP and ScP. The data is examined for evidence of an ultra-low velocity zone (ULVZ) by identifying and modeling precursors to PcP. Precursory arrivals to PcP may be generated by the interaction of PcP with a thin layer above the core-mantle boundary (CMB). One-dimensional modeling demonstrates that standard earth models of the core-mantle boundary, which lack ULVZ structure, cannot produce the observed PcP data. …

Geology – Future Continent, Joy Wulke

The Transdisciplinary STEAM+ Journal

Terra Mirabila, a multi-media presentation illustrating the geological story of Stony Creek Granite back through complex sequence of geological events that spanned some 600 million years of early history.

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

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

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

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

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

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

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

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

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

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

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

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 …

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

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

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 …