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Full-Text Articles in Physical Sciences and Mathematics

Spectral Analysis Of Ground Penetrating Radar Response To Thin Sedimentary Layers, Swagata Guha, Sarah E. Kruse, E. E. Wright, U. E. Kruse Dec 2005

Spectral Analysis Of Ground Penetrating Radar Response To Thin Sedimentary Layers, Swagata Guha, Sarah E. Kruse, E. E. Wright, U. E. Kruse

Geology Faculty Publications

Ground penetrating radar (GPR) systems utilized in studies of sedimentary deposits generate wavelengths (tens of centimeters) that are commonly much longer than the thickness of bedding (often millimeters to centimeters) within the target strata. Where this is the case, radar profiles represent interference patterns. Simple models of radar response to sequences of thin beds such as those found in coastal deposits show potentially detectable spectral shifts toward higher frequencies in radar returns. Spectral analysis of radar data over barrier beach deposits at Waites Island, South Carolina, shows that returns from packages with heavy mineral laminations are shifted toward higher frequencies …


Modeling Tephra Sedimentation From A Ruapehu Weak Plume Eruption, Costanza Bonadonna, J. C. Phillips, B. F. Houghton Aug 2005

Modeling Tephra Sedimentation From A Ruapehu Weak Plume Eruption, Costanza Bonadonna, J. C. Phillips, B. F. Houghton

Geology Faculty Publications

We present a two-dimensional model for sedimentation of well-mixed weak plumes, accounting for lateral spreading of the cloud, downwind advection, increase of volumetric flux in the rising stage, and particle transport during fallout. The 17 June 1996 subplinian eruption of Ruapehu produced a bent-over plume that rose to a height of 8.5 km in a wind field with an average velocity of 24 m s−1 and generated a narrow deposit on land extending up to 200 km from vent. The sedimentation from the Ruapehu plume was dominated by coarse ash, with all the blocks and most of the lapilli …


Geochemistry Of Serpentinized Peridotites From The Mariana Forearc Conical Seamount, Odp Leg 125: Implications For The Elemental Recycling At Subduction Zones, Ivan P. Savov, Jeffrey G. Ryan, Massimo D'Antonio, Katherine Kelley, Patrick Mattie Apr 2005

Geochemistry Of Serpentinized Peridotites From The Mariana Forearc Conical Seamount, Odp Leg 125: Implications For The Elemental Recycling At Subduction Zones, Ivan P. Savov, Jeffrey G. Ryan, Massimo D'Antonio, Katherine Kelley, Patrick Mattie

Geology Faculty Publications

Recent examinations of the chemical fluxes through convergent plate margins suggest the existence of significant mass imbalances for many key species: only 20–30% of the to-the-trench inventory of large-ion lithophile elements (LILE) can be accounted for by the magmatic outputs of volcanic arcs. Active serpentinite mud volcanism in the shallow forearc region of the Mariana convergent margin presents a unique opportunity to study a new outflux: the products of shallow-level exchanges between the upper mantle and slab-derived fluids. ODP Leg 125 recovered serpentinized harzburgites and dunites from three sites on the crests and flanks of the active Conical Seamount. These …


Probabilistic Modeling Of Tephra Dispersal: Hazard Assessment Of A Multiphase Rhyolitic Eruption At Tarawera, New Zealand, Costanza Bonadonna, Charles B. Connor, B. F. Houghton, Laura Connor, Marc A. Byrne, A. Laing, T. K. Hincks Mar 2005

Probabilistic Modeling Of Tephra Dispersal: Hazard Assessment Of A Multiphase Rhyolitic Eruption At Tarawera, New Zealand, Costanza Bonadonna, Charles B. Connor, B. F. Houghton, Laura Connor, Marc A. Byrne, A. Laing, T. K. Hincks

Geology Faculty Publications

The Tarawera Volcanic Complex comprises 11 rhyolite domes formed during five major eruptions between 17,000 B.C. and A.D. 1886, the first four of which were predominantly rhyolitic. The only historical event erupted about 2 km3 of basaltic tephra fall (A.D. 1886). The youngest rhyolitic event erupted a tephra fall volume more than 2 times larger and covered a wider area northwest and southeast of the volcano (∼A.D. 1315 Kaharoa eruption). We have used the Kaharoa scenario to assess the tephra fall hazard from a future rhyolitic eruption at Tarawera of a similar scale. The Plinian phase of this eruption …


Evidence For Static Stress Changes Triggering The 1999 Eruption Of Cerro Negro Volcano, Nicaragua And Regional Aftershock Sequences, M. Diez, P. C. La Femina, Charles B. Connor, W. Strauch, Tenorio V. Tenorio Feb 2005

Evidence For Static Stress Changes Triggering The 1999 Eruption Of Cerro Negro Volcano, Nicaragua And Regional Aftershock Sequences, M. Diez, P. C. La Femina, Charles B. Connor, W. Strauch, Tenorio V. Tenorio

Geology Faculty Publications

Remarkable evidence of coupling between tectonic and magmatic events emerges from investigation of three tectonic earthquakes, aftershock sequences and eruption of Cerro Negro volcano, Nicaragua in 1999. Here, we explain this coupling through static stress changes following three Mw 5.2 earthquakes. We use focal mechanism solutions to estimate fault system geometry and magnitude of slip from these events, which are then used to calculate the change in minimum horizontal principal stress (σ3) for the region and the change in Coulomb failure stress on optimally oriented fault planes. Results of these simulations indicate that σ3 was reduced by …


The Reflection Of Karst In The Online Mirror: A Survey Within Scientific Databases, 1960-2005, Lee J. Florea, Beth Fratesi, Todd A. Chavez Jan 2005

The Reflection Of Karst In The Online Mirror: A Survey Within Scientific Databases, 1960-2005, Lee J. Florea, Beth Fratesi, Todd A. Chavez

Academic Resources Faculty and Staff Publications

The field of cave and karst science is served by a literature that is dispersed across far-flung topical journals, government publications, and club newsletters. As part of an inter-institutional project to globalize karst information (KIP, the Karst Information Portal), the USF Library undertook a structured battery of literature searches to map the domain of karst literature. The study used 4,300 individual searches and four literature databases: GeoRef, BIOSIS, Anthropology Plus, and GPO Access. The searches were based on a list of 632 terms including 321 karst-related keywords culled from three leading encyclopedias and glossaries of cave and karst science. An …


The Reflection Of Karst In The Online Mirror: A Survey Within Scientific Databases, 1960-2005, Lee J. Florea, Beth Fratesi, Todd A. Chavez Jan 2005

The Reflection Of Karst In The Online Mirror: A Survey Within Scientific Databases, 1960-2005, Lee J. Florea, Beth Fratesi, Todd A. Chavez

Todd A. Chavez

The field of cave and karst science is served by a literature that is dispersed across far-flung topical journals, government publications, and club newsletters. As part of an inter-institutional project to globalize karst information (KIP, the Karst Information Portal), the USF Library undertook a structured battery of literature searches to map the domain of karst literature. The study used 4,300 individual searches and four literature databases: GeoRef, BIOSIS, Anthropology Plus, and GPO Access. The searches were based on a list of 632 terms including 321 karst-related keywords culled from three leading encyclopedias and glossaries of cave and karst science. An …


Partitions, Compartments And Portals: Cave Development In Internally Impounded Karst Masses, R. Armstrong L. Osborne Jan 2005

Partitions, Compartments And Portals: Cave Development In Internally Impounded Karst Masses, R. Armstrong L. Osborne

International Journal of Speleology

Dykes and other vertical bodies can act as aquicludes within bodies of karst rock. These partitions separate isolated bodies of soluble rock called compartments. Speleogenetically each compartment will behave as a small impounded-karst until the partition becomes breached. Breaches through partitions, portals, allow water, air and biota including humans to pass between sections of caves that were originally isolated.


Conceptualisation Of Speleogenesis In Multi-Storey Artesian Systems: A Model Of Transverse Speleogenesis, Alexander Klimchouk Jan 2005

Conceptualisation Of Speleogenesis In Multi-Storey Artesian Systems: A Model Of Transverse Speleogenesis, Alexander Klimchouk

International Journal of Speleology

Conceptual and respective quantitative models of speleogenesis/karstification developed for unconfined aquifers do not adequately represent speleogenesis in confined settings. A conceptual model for speleogenesis in confined settings is suggested, based on views about hydraulic continuity in artesian basins and close cross-formation communication between aquifers in multi-storey artesian systems. Soluble units sandwiched between insoluble porous/fissured formations (common aquifers) initially serve as low permeability beds separating aquifers in a confined system. Conduits evolve as result of vertical hydraulic communication between aquifers across the soluble bed ("transverse speleogenesis"). Recharge from the adjacent aquifer is dispersed and uniform, and flow paths across the soluble …


Agraphorura Calvoi N. Sp. From Venezuelan Caves (Collembola: Onychiuridae), Javier I. Arbea Jan 2005

Agraphorura Calvoi N. Sp. From Venezuelan Caves (Collembola: Onychiuridae), Javier I. Arbea

International Journal of Speleology

A new species of Agraphorura (Collembola: Poduromorpha: Onychiuridae) from caves in the Nort-West of Venezuela is described. A. calvoi n. sp. can be distinguished from its congeners by the following combination of characters: antennal organ III with four papillae, 32/133/33343 dorsal pseudocellar formula, 3/000/0112 ventral pseudocellar, subcoxae each with two pseudocelli, postantennal organ with 7-9 vesicles, unguiculus with a basal lamella, tibiotarsi I-III with 19,19,18 setae (distal whorl of 9 setae). A table with the differential characters, as well as an identifi cation key for all of the known species of Agraphorura are provided.


Cross-Formational Flow, Diffluence And Transfluence Observed In St. Beatus Cave And Sieben Hengste (Switzerland), Philipp Häuselmann Jan 2005

Cross-Formational Flow, Diffluence And Transfluence Observed In St. Beatus Cave And Sieben Hengste (Switzerland), Philipp Häuselmann

International Journal of Speleology

Observations in St. Beatus Cave and neighbouring caves revealed complex water flowpaths that can be used for explaining the behaviour of tracing experiments. The observations prove that even in vadose conditions, cross-formational flow, diffluences and transfluences are a quite common feature. Therefore, also the vadose karst has a very complex organisation.


Radon In Caves, Arrigo A. Cigna Jan 2005

Radon In Caves, Arrigo A. Cigna

International Journal of Speleology

The physical characteristics of radon are reported as well as its sources,the transport in rock and its behaviour in caves. Then, the instruments,both active and passive, used for the measurement of radon concentration are discussed by taking into account their respective advantages and disadvantages for the use in the cave environment. Since in many countries radon is the object of regulations that were adopted for radiation protection purposes, this aspect is examined and the recommendations issued by international organisations and enforced in different countries are reported. Materials, methods and other remarks on the limits implementation are also listed with the …


Cavity-Based Secondary Mineralization In Volcanic Tuffs Of Yucca Mountain, Nevada: A New Type Of The Polymineral Vadose Speleothem, Or A Hydrothermal Deposit?, Yuri V. Dublyansky, Sergey Z. Smirnov Jan 2005

Cavity-Based Secondary Mineralization In Volcanic Tuffs Of Yucca Mountain, Nevada: A New Type Of The Polymineral Vadose Speleothem, Or A Hydrothermal Deposit?, Yuri V. Dublyansky, Sergey Z. Smirnov

International Journal of Speleology

Secondary minerals (calcite, chalcedony, quartz, opal, fl uorite, heulandite, strontianite) residing in open cavities in the Miocene rhyolite tuffs of Yucca Mountain, Nevada have been interpreted by some researchers as "speleothemic" formations, deposited as a result of downward infi ltration of meteoric waters (DOE, 2001, Whelan et al., 2002). The major mineral of the paragenesis, calcite, shows spectacular trend of the textural and crystal morphology change: from anhedral granular occurrences, through (optional) platelet, bladed and scepter varieties, to euhedral blocky morphologies. The trend is consistent with the overall decrease in the supesaturation of the mineral forming solution. Stable isotope properties …


Sedimentological Characteristics And Internal Architecture Of Two Overwash Fans From Hurricanes Ivan And Jeanne, Mark H. Horwitz, Ping Wang Jan 2005

Sedimentological Characteristics And Internal Architecture Of Two Overwash Fans From Hurricanes Ivan And Jeanne, Mark H. Horwitz, Ping Wang

Geology Faculty Publications

Extensive overwash occurred along the Florida coast during the passage of four strong hurricanes in 2004, providing an excellent opportunity to study the spatial patterns and sedimentary architecture of washover deposits. Detailed 3D sedimentological characteristics of two of the overwash fans were studied through coring, trenching, and ground penetration radar surveys. The first washover-fan complex, deposited by hurricanes Frances and Jeanne is located on the Atlantic facing Hutchinson Island in southeastern Florida. The second fan, deposited by hurricane Ivan is located on the Gulf-facing Santa Rosa Island in northwestern Florida. Subsurface imaging using a 250 MHz Ground penetrating radar profiling …