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Articles 661 - 690 of 1881

Full-Text Articles in Earth Sciences

Short- And Long-Term Trends In Ecological Interactions: From Predator-Prey Interactions To Phanerozoic Diversification, Subhronil Mondal Nov 2014

Short- And Long-Term Trends In Ecological Interactions: From Predator-Prey Interactions To Phanerozoic Diversification, Subhronil Mondal

USF Tampa Graduate Theses and Dissertations

During the last two decades, a broad spectrum of short- and long-term studies on different taxonomic groups has enriched our understanding about how dynamics of taxonomic and ecological diversification have changed through geologic time. There are two major issues that have impacted these studies: the quality and quantity of data used are often insufficient in various ways and the methods used may produce results that are more equivocal than supposed. To investigate these issues more fully, this dissertation focuses on studies on two major aspects: 1) short-term studies examining the nature of successful and unsuccessful predatory attacks on Plio-Pleistocene bivalves; …


Verification And Comparison Of Two Commonly Used Numerical Modeling Systems In Hydrodynamic Simulation At A Dual-Inlet System, West-Central Florida, Ming Xie Nov 2014

Verification And Comparison Of Two Commonly Used Numerical Modeling Systems In Hydrodynamic Simulation At A Dual-Inlet System, West-Central Florida, Ming Xie

USF Tampa Graduate Theses and Dissertations

Numerical modeling systems are very important tools to study tidal inlets. In order to test its capability and accuracy of solving multi-inlet system problems, this study selected two widely used numerical modeling systems: Coastal Modeling System (CMS) and Delft3D Modeling Package. The hydrodynamics modules of the two modeling systems were tested at John's Pass and Blind Pass, Florida, a dual-inlets system, based on a similar modeling scheme. Detailed bathymetric surveys and hydraulic measurements were conducted to collect water depths, tide conditions, wave and current velocities as the input data as well as verification data for the models.

A comparison study …


Redox Chemistry In The Phosphorus Biogeochemical Cycle, Matthew A. Pasek, Jacqueline M. Sampson, Zachary Atlas Oct 2014

Redox Chemistry In The Phosphorus Biogeochemical Cycle, Matthew A. Pasek, Jacqueline M. Sampson, Zachary Atlas

School of Geosciences Faculty and Staff Publications

The element phosphorus (P) controls growth in many ecosystems as the limiting nutrient, where it is broadly considered to reside as pentavalent P in phosphate minerals and organic esters. Exceptions to pentavalent P include phosphine—PH3—a trace atmospheric gas, and phosphite and hypophosphite, P anions that have been detected recently in lightning strikes, eutrophic lakes, geothermal springs, and termite hindguts. Reduced oxidation state P compounds include the phosphonates, characterized by C−P bonds, which bear up to 25% of total organic dissolved phosphorus. Reduced P compounds have been considered to be rare; however, the microbial ability to use reduced P …


Groundwater Controls On Physical And Chemical Processes In Streamside Wetlands And Headwater Streams In The Kenai Peninsula, Alaska, Michael Kroh Callahan Oct 2014

Groundwater Controls On Physical And Chemical Processes In Streamside Wetlands And Headwater Streams In The Kenai Peninsula, Alaska, Michael Kroh Callahan

USF Tampa Graduate Theses and Dissertations

For this dissertation I studied groundwater and surface water interactions in the Kenai Lowlands, Alaska. In particular, I examine two important aspects of groundwater and surface water interactions: 1) Groundwater's influence on surface-water temperature; and 2) Groundwater's role in forming hydrologic flow paths that can connect uplands to streamside wetlands and streams. Chapter 2 investigates the controls on stream temperature in salmon-bearing headwater streams in two common hydrogeologic settings: 1) drainage-ways, which are low-gradient streams that flow through broad valleys; and 2) discharge-slopes, which are high gradient streams that flow through narrow valleys. The results from chapter 2 showed significant …


The Biogeochemical Cycling Of Zinc And Zinc Isotopes In The North Atlantic Ocean, Tim M. Conway, Seth G. John Oct 2014

The Biogeochemical Cycling Of Zinc And Zinc Isotopes In The North Atlantic Ocean, Tim M. Conway, Seth G. John

School of Geosciences Faculty and Staff Publications

Zinc (Zn) is a marine micronutrient, with an overall oceanic distribution mirroring the major macronutrients, especially silicate. Seawater Zn isotope ratios (δ66Zn) are a relatively new oceanographic parameter which may offer insights into the biogeochemical cycling of Zn. To date, the handful of published studies of seawater δ66Zn show the global deep ocean to be both remarkably homogeneous (approximately +0.5‰) and isotopically heavier than the marine sources of Zn (+0.1 to +0.3‰). Here we present the first high‐resolution oceanic section of δ66Zn, from the U.S. GEOTRACES GA03 North Atlantic Transect, from Lisbon to …


Speleothem And Biofilm Formation In A Granite/Dolerite Cave, Northern Sweden, Therese Sallstedt, Magnus Ivarsson, Johannes Lundberg, Rabbe Sjöberg, Juan Ramón Vidal Romaní Sep 2014

Speleothem And Biofilm Formation In A Granite/Dolerite Cave, Northern Sweden, Therese Sallstedt, Magnus Ivarsson, Johannes Lundberg, Rabbe Sjöberg, Juan Ramón Vidal Romaní

International Journal of Speleology

Tjuv-Antes grotta (Tjuv-Ante's Cave) located in northern Sweden is a round-abraded sea cave ('tunnel cave'), about 30 m in length, formed by rock-water abrasion in a dolerite dyke in granite gneiss. Abundant speleothems are restricted to the inner, mafic parts of the cave and absent on granite parts. The speleothems are of two types: cylindrical (coralloid, popcorn-like), and flowstone (thin crusts). Coralloids correspond to terrestrial stromatolite speleothems in which layers of light calcite alternate with dark, silica-rich laminae. The dark laminae are also enriched in carbon and contain incorporated remains of microorganisms. Two types of microbial communities can be distinguished …


Caves In Caves: Evolution Of Post-Depositional Macroholes In Stalagmites, Nurit Shtober-Zisu, Henry P. Schwarcz, Tom Chow, Christopher R. Omelon, Gordon Southam Sep 2014

Caves In Caves: Evolution Of Post-Depositional Macroholes In Stalagmites, Nurit Shtober-Zisu, Henry P. Schwarcz, Tom Chow, Christopher R. Omelon, Gordon Southam

International Journal of Speleology

In a previous paper (Shtober-Zisu et al., 2012) we described millimeter to centime-sized fluid-free holes within the interiors of stalagmites of widely varying origin. We present here further observations of this phenomenon, using X-ray tomography, macroscopic and microscopic observation of sections of twenty-six stalagmites from various sites in North America and the Caribbean region. We can distinguish three types of cavities in speleothems: primary µm-sized fluid inclusions; mm to cm sized holes, aligned along the stalagmite growth axis which are clearly syngenetic; and µm to cm-sized holes away from the growth axis (“off-axis holes or OAHs”) deeply buried inside their …


Time, Money, And Melting Ice: Proposal For A Coopertive Study Of The World’S Cave Ice In A Race Against Climate Change, George Veni, Lewis Land, Aurel Perşoiu Aug 2014

Time, Money, And Melting Ice: Proposal For A Coopertive Study Of The World’S Cave Ice In A Race Against Climate Change, George Veni, Lewis Land, Aurel Perşoiu

The International Workshop on Ice Caves

Climate change is a global phenomenon that is melting and threatening to melt ice deposits in many of the world’s ice caves. The National Cave and Karst Research Institute of the USA is concerned that major and important paleoclimate and paleoenvironmental records stored in cave ice will soon be lost, and is proposing an international collaborative effort to overcome funding and logistical challenges to sample and analyze at least a representative collection of ice from several regions before further melting occurs.


Some New Potential Subterranean Glaciation Research Sites From Velebit Mt. (Croatia), Neven Bočić, Nenad Buzjak, Zoltan Kern Aug 2014

Some New Potential Subterranean Glaciation Research Sites From Velebit Mt. (Croatia), Neven Bočić, Nenad Buzjak, Zoltan Kern

The International Workshop on Ice Caves

Despite the frequent reports about their shrinkage detailed survey of the major subterranean ice deposits is still lacking in Croatia. Here we present cave maps and detailed description of cave ice accumulation from five caves of the Velebit Mt. Morphological constraints allowed ice volume estimation for four of them. Ice volumes were estimated as ~1500 m3 at the Gavranova Pit in 1999, 100 m3 at Štirovača ice cave in 1987, 150 m3 at Japagina 3 in 2000, 1500 m3 at Kugina ice cave in 2004. These new records provide reference data for future studies to evaluate …


Climate Study In An Abandoned Auto Tunnel In Alaska, Usa, Andreas Pflitsch, David Holmgren Aug 2014

Climate Study In An Abandoned Auto Tunnel In Alaska, Usa, Andreas Pflitsch, David Holmgren

The International Workshop on Ice Caves

An abandoned auto tunnel in south central Alaska in an elevation of 118 m above sea level seemed to be a perfect laboratory for studying the evolution of ice speleothems in a yearly cycle. More than 1,500 ice forms like stalagmites, stalactites, columns in various shape and arrangements, developed in just 2 month to a high up to 6 meters and lasted for another 5 to 6 month. In October just the remains of the melted ice in rings and rectangular patterns of a white powder could be found. Unfortunately the mostly sealed tunnel was opened in January 2014 by …


The Monica (Monitoring Of Ice Within Caves) Project: A Multidisciplinary Approach For The Geophysical And Paleoclimatic Characterization Of Permanent Ice Deposits In The Southeastern Alps, Renato R. Colucci, Emanuele Forte, Barbara Stenni, Marco Basso Bondini, Mauro Colle Fontana, Costanza Del Gobbo, Daniele Fontana, Doriana Belligoi, Valter Maggi, Marco Filipazzi Aug 2014

The Monica (Monitoring Of Ice Within Caves) Project: A Multidisciplinary Approach For The Geophysical And Paleoclimatic Characterization Of Permanent Ice Deposits In The Southeastern Alps, Renato R. Colucci, Emanuele Forte, Barbara Stenni, Marco Basso Bondini, Mauro Colle Fontana, Costanza Del Gobbo, Daniele Fontana, Doriana Belligoi, Valter Maggi, Marco Filipazzi

The International Workshop on Ice Caves

On days 30 September and 1-2 October 2013, a 7.8 m long ice core has been extracted from a permanent ice cave deposit in the Southeastern Alps (Vasto’s cave, Mt.Canin - Julian Alps). Each 20 to 100 cm long section of the ice core have been immediately stored in plastic bags and preserved thanks to dry ice. The ice samples, thanks to the helicopter, has been subsequently brought on valley and promptly stored in a refrigerated van, made available by BoFrost. Thus the ice cores has been transported intact to the EUROCOLD laboratory in Milan. These operations have been carried …


Ice Caves On Extraterrestrial Bodies: What Are The Prospects For Speleogenesis And Detection?, Penelope J. Boston Aug 2014

Ice Caves On Extraterrestrial Bodies: What Are The Prospects For Speleogenesis And Detection?, Penelope J. Boston

The International Workshop on Ice Caves

Potential mechanisms for creating cavities in icy extraterrestrial bodies have been tentatively explored by several authors. On one hand we have examples of mechanisms that create caves in water ice here on Earth. In addition, there may be unique mechanisms on other Solar System objects that do not occur on Earth but might produce cavities, e.g. sublimation of comets upon perihelion passage. The methods of detecting such cavities depend upon the nature of the icy body in question, the potential for orbital or landed missions to visit those bodies in the future, and remote or landed methods for detecting the …


Internal Drainage Of Glaciers And Its Origin, Bulat R. Mavlyudov Aug 2014

Internal Drainage Of Glaciers And Its Origin, Bulat R. Mavlyudov

The International Workshop on Ice Caves

Ways of occurrence of elements of an internal drainage of glaciers and also origin of internal drainage systems as a whole are considered. It is shown that elements of an internal drainage can be formed either on the base of fissures and crevasses or by incision of water streams into ice from glacier surface. The basic way of glacier drainage is formed on the base of sliding plane which is formed closely to glacier bed and smooth all roughnesses of the bed. Spreading of water on the surface of this plane during spring time forms not effective drainage system however …


Full Proceedings Of The 6th International Workshop On Ice Caves, National Cave And Karst Research Institute Aug 2014

Full Proceedings Of The 6th International Workshop On Ice Caves, National Cave And Karst Research Institute

The International Workshop on Ice Caves

Welcome to the Sixth International Workshop on Ice Caves (IWIC VI) in Idaho Falls, Idaho, USA. The National Cave and Karst Research Institute is pleased to host the first IWIC to meet outside of Europe, which will include speakers from over half a dozen countries in Europe, Asia, and North America. The conference setting in this mountainous region of the northwestern United States will provide conference participants with multiple opportunities to visit ice caves, including two trips to Craters of the Moon National Monument. This is also the first IWIC to examine ice in lava tube caves.


The Sandy Glacier Cave Project: The Study Of Glacial Recession From Within, Eduardo L. Cartaya Aug 2014

The Sandy Glacier Cave Project: The Study Of Glacial Recession From Within, Eduardo L. Cartaya

The International Workshop on Ice Caves

The Sandy Glacier Cave Project is a National Speleological Society (NSS) sponsored study on the unique system of glacier caves located on the Sandy Glacier on the western flank of Mt Hood, Oregon. While the study primarily targets the structure, layout and ice volume change of the ever moving cave system by conducting annual grade 5 surveys, numerous tangential observations and trends have been recorded that are of great interest to the study of glacial recession, watershed hydrology, micro-biology and astro-biology, as well as the study of organic specimens and remains being thawed out of the ice mass by the …


On The Mechanism Of The Naturally Formed Ice Spikes, Hi-Ryong Byun, Chang-Kyun Park Aug 2014

On The Mechanism Of The Naturally Formed Ice Spikes, Hi-Ryong Byun, Chang-Kyun Park

The International Workshop on Ice Caves

The formations of the ice spike, which is the ice bar risen upward from the ice surface in bowl and has been known as a mystery of the Mt. Mai in Jinan, Jeonbuk Korea, are observed and analyzed through the observation records on more than 60,000 bowls of water for 8 years and 7 days and nights' consecutive meteorological observations. Experiments making the ice bar in the refrigerator have also performed. As results, it is verified that the ice spike is not a mystery but a naturally grown ice bar caused by the volume expansion centralized to a certain point …


Introduction For Proceedings Of The 6th International Workshop On Ice Caves, National Cave And Karst Research Institute Aug 2014

Introduction For Proceedings Of The 6th International Workshop On Ice Caves, National Cave And Karst Research Institute

The International Workshop on Ice Caves

No abstract provided.


Characterization Of Two Permanent Ice Cave Deposits In The Southeastern Alps (Italy) By Means Of Ground Penetrating Radar (Gpr), Renato R. Colucci, Daniele Fontana, Emanuele Forte Aug 2014

Characterization Of Two Permanent Ice Cave Deposits In The Southeastern Alps (Italy) By Means Of Ground Penetrating Radar (Gpr), Renato R. Colucci, Daniele Fontana, Emanuele Forte

The International Workshop on Ice Caves

In order to assess the thickness and the inner structure of some permanent ice deposits in two high elevated alpine karstic caves of the Canin massif (Alpi Giulie, Italy), we performed several multi frequency Ground Penetrating Radar (GPR) surveys. The surveys have been conducted within the project MONICA (MOnitoring of Ice within Caves), aimed at the paleoclimatic characterization of the considered cave ice deposits. GPR surveys have proved to be crucial also in finding the most suitable place for carrying out a drilling core. This has been particularly useful in the Vasto’s ice cave (VIC) in which the direct/visual estimation …


New Research In Cave Ledenica In Bukovi Vrh On Velebit Mt In Croatian Dinaric Karst, Mladen Garasic Aug 2014

New Research In Cave Ledenica In Bukovi Vrh On Velebit Mt In Croatian Dinaric Karst, Mladen Garasic

The International Workshop on Ice Caves

No abstract provided.


The Influence Of Karst Topography To Ice Cave Occurrence - Example Of Ledena Jama In Lomska Duliba (Croatia), Nenad Buzjak Aug 2014

The Influence Of Karst Topography To Ice Cave Occurrence - Example Of Ledena Jama In Lomska Duliba (Croatia), Nenad Buzjak

The International Workshop on Ice Caves

The research of cave microclimate in general contributes to a better understanding of physical and chemical processes in complex karst geoecosystems. Special challenges for researchers are ice caves. This preliminary report is a part of the project dedicated to the research of deep caves on Velebit Mt. and pointed to the influence of the large karst depression microclimate to cave microclimate, e.g. ice and snow accumulation. The one year study using T/RH data loggers was conducted in Lomska duliba valley (Velebit Mt.) known for frequent temperature inversion and low air temperature, and in partially ice-snow filled Ledena jama (Ice shaft) …


Study Of Multiyear Ice In Medeo Cave (North Ural), Yuri Ivanovich Stepanov, Alexandr Alexandrovich Tainitskiy, Alexandr Valerievich Kichigin, Olga Ivanovna Kadebskaya, Bulat Rafaelevich Mavlyudov Aug 2014

Study Of Multiyear Ice In Medeo Cave (North Ural), Yuri Ivanovich Stepanov, Alexandr Alexandrovich Tainitskiy, Alexandr Valerievich Kichigin, Olga Ivanovna Kadebskaya, Bulat Rafaelevich Mavlyudov

The International Workshop on Ice Caves

The uniqueness of cave ice study lies in characteristic and simulation of continental climate and predictability of its changes. In this study carried out GPR studies in a remote cave Medeo. The cave is located in the territory of Srednevisherski area of West Ural folded zone carbon-bearing karst. The aim of the study was to examine the power and homogeneity of perennial ice formations. According to the results for the first time was defined the power of multi-year ice and built a three-dimensional model of sediment. The cave ice is more enriched with mineral ingredient in comparison with aboveground ice …


Numerical Modeling Of Formation Of A Static Ice Cave – Ningwu Ice Cave, Shanxi, China, Yaolin Shi, Shaohua Yang Aug 2014

Numerical Modeling Of Formation Of A Static Ice Cave – Ningwu Ice Cave, Shanxi, China, Yaolin Shi, Shaohua Yang

The International Workshop on Ice Caves

Ningwu Ice Cave in Shanxi province, China, is the largest Ice cave in China. We use Finite Element Method(FEM) to model the process of heat transfer in the ice cave. We not only calculate thermal conduction in spring, summer and fall, but also calculate the convective heat transfer in winter by introducing an equivalent thermal conductivity of cave air. Our computation shows that the ice cave can be formed within a decade, and reach a stable cyclic state in few centuries. Our calculation also shows that if people set a trap door at the ice cave entrance, especially in winter, …


Characterization Of The Depositional Environment Of Phreatic Overgrowths On Speleothems In The Littoral Caves Of Mallorca (Spain): A Physical, Geochemical, And Stable Isotopic Study, Liana Marie Boop Jul 2014

Characterization Of The Depositional Environment Of Phreatic Overgrowths On Speleothems In The Littoral Caves Of Mallorca (Spain): A Physical, Geochemical, And Stable Isotopic Study, Liana Marie Boop

USF Tampa Graduate Theses and Dissertations

Phreatic overgrowths on speleothems (POS) are one of many sea-level proxies available to Quaternary geologists in Mallorca; these carbonate encrustations form at the air-water interface in cave passages flooded with brackish water. POS are ideal for reconstruction of western Mediterranean sea level because they are widespread in Mallorca's caves, can be precisely dated by U-series methods, constrain sea-level stands to sub-meter elevation, and are well preserved and accessible in the subterranean environment.

This research investigates the POS depositional environment, which is relatively understudied compared to the other proxies used for sea-level reconstructions. This disparity has led to assumptions on many …


Interpolating Beach Profile Data Using Linear And Non-Linear Functions, Lance Calloway Croft Jul 2014

Interpolating Beach Profile Data Using Linear And Non-Linear Functions, Lance Calloway Croft

USF Tampa Graduate Theses and Dissertations

ABSTRACT

Beach and nearshore surveys are conducted in a variety of ways, the most commonly used being the level-and-transit method; because it is inexpensive, time conducive and highly accurate. Specifically, beach surveys are conducted to better understand cross-shore, long-shore sediment transport processes, as well as to quantify volume changes, which are used to evaluate beach performance. In this study, a section of the beach on Sand Key, FL was surveyed using rod-and-transit. In addition to the commonly used linear data analysis, a non-linear analysis was conducted using NURBS (Non-Uniform Rational B-Splines).

Survey data was collected within a short time window …


Timing Of Svalbard/Barents Sea Ice Sheet Decay During The Last Glacial Termination, Tasha Snow Jul 2014

Timing Of Svalbard/Barents Sea Ice Sheet Decay During The Last Glacial Termination, Tasha Snow

USF Tampa Graduate Theses and Dissertations

The Arctic and North Atlantic underwent significant climactic changes since the Last Glacial Maximum (25,000 years before present (1950 AD); ka BP), but offsets in the timing of events between the two regions are poorly constrained due to age model uncertainties that arise from changing radiocarbon reservoir ages. Here, we use a relatively high-resolution, multi-proxy stable isotope and sedimentologic dataset from Eastern Fram Strait (ODP Leg 162 Site 986) marine sediments to constrain the timing of Svalbard/Barents Sea Ice Sheet decay and infer deglacial reservoir ages over the last 30 ka. We use magnetic susceptibility, inorganic and organic carbon, foraminiferal …


Use Of System Dynamics Modeling To Explicate The Theory-Of-Change Of A Social Marketing Innovation, Brian J. Biroscak Jul 2014

Use Of System Dynamics Modeling To Explicate The Theory-Of-Change Of A Social Marketing Innovation, Brian J. Biroscak

USF Tampa Graduate Theses and Dissertations

Community coalitions are an important part of the public health milieu and thus subject to many of the same external pressures as public health organizations--including changes in required strategic orientation. Many funding agencies have shifted their funding agenda from program development to policy change. Thus, the Florida Prevention Research Center created the Community-Based Prevention Marketing for Policy Development framework to teach community coalitions how to apply social marketing to policy change. The dissertation research reported here was designed to explicate the framework's theory-of-change. The research question was: "What are the linkages and connections between CBPM inputs, activities, immediate outcomes, intermediate …


A Multi-Proxy Approach To Understanding Abrupt Climate Change And Laurentide Ice Sheet Melting History Based On Gulf Of Mexico Sediments, Clare Carlisle Williams Jun 2014

A Multi-Proxy Approach To Understanding Abrupt Climate Change And Laurentide Ice Sheet Melting History Based On Gulf Of Mexico Sediments, Clare Carlisle Williams

USF Tampa Graduate Theses and Dissertations

During the last deglaciation (ca. 24-10 ka thousand years ago (ka)), the North American Laurentide Ice Sheet (LIS) was a major source of meltwater to the Arctic Ocean, North Atlantic Ocean, and the Gulf of Mexico (GOM), and it is hypothesized that meltwater routing played an important role in regulating Late Quaternary millennial-scale climate variability, via its influence on Atlantic Meridional Overturning Circulation (AMOC). For example, the meltwater routing hypothesis predicts that a rerouting of meltwater from the GOM to the North Atlantic and/or Arctic Oceans resulted in a decrease of North Atlantic Deep Water (NADW) formation and subsequent cooling …


Evolution And Equilibration Of Artificial Morphologic Perturbations In The Form Of Nearshore Berm Nourishments Along The Florida Gulf Coast, Katherine Emily Brutsché Jun 2014

Evolution And Equilibration Of Artificial Morphologic Perturbations In The Form Of Nearshore Berm Nourishments Along The Florida Gulf Coast, Katherine Emily Brutsché

USF Tampa Graduate Theses and Dissertations

Inlets and channels are dredged often to maintain navigation safety. It is beneficial to reintroduce the dredged material back into the littoral system, in the form of beach or nearshore nourishments. Nourishment in the nearshore is becoming an increasingly utilized method, particularly for dredged material that contains more fine sediment than the native beach. This research examines the morphologic evolution of two different nearshore nourishments. A nearshore berm was constructed at Fort Myers Beach, Florida using mixed-sized sediment dredged from a nearby channel. The nearshore berm was placed in water depths between 1.2 and 2.4 m with the berm crest …


Volcanism-Induced Karst Landforms And Speleogenesis, In The Ankarana Plateau (Madagascar). Hypothesis And Preliminary Research, Eric Gilli Jun 2014

Volcanism-Induced Karst Landforms And Speleogenesis, In The Ankarana Plateau (Madagascar). Hypothesis And Preliminary Research, Eric Gilli

International Journal of Speleology

The Ankarana is a limestone plateau in the northern part of Madagascar, where a cave system, more than 120 km long, has been explored. The plateau is bordered by volcanoes and is cut across by several canyons. An analysis of surface landforms and caves suggests that the karst genesis was probably initiated by volcanism beneath an impervious cover. Volcanic bulging and magma intrusions may have favored a basalt-limestone assimilation process and metamorphism. The ascent of deep volcanic fluids (CO2 and SO2) from magma degassing and from limestone metamorphism, may explain the speleogenesis. Once denuded, the karst evolved …


A Seasonally Modulated Earthquake Swarm Near Maupin, Oregon, Jochen Braunmiller, John L. Nabelek, Anne M. Trehu Jun 2014

A Seasonally Modulated Earthquake Swarm Near Maupin, Oregon, Jochen Braunmiller, John L. Nabelek, Anne M. Trehu

School of Geosciences Faculty and Staff Publications

From December 2006 to November 2011, the Pacific Northwest Seismic Network (PNSN) reported 467 earthquakes in a swarm 60 km east of Mt Hood near the town of Maupin, Oregon. The swarm included 20 MD ≥ 3.0 events, which account for over 80 per cent of the cumulative seismic moment release of the sequence. Relocation of 45 MD≥ 2.5 earthquakes and moment tensor analysis of nine 3.3 ≤ Mw ≤ 3.9 earthquakes reveals right-lateral strike-slip motion on a north-northwest trending, 70° west dipping, 1 km2 active fault patch at about 17 km depth. The swarm started …