Physical Sciences and Mathematics Commons^™

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 …

Nutrient Enrichment Studies Of Natural Phytoplankton Populations In The Lower Hillsborough River Conducted On October 10 - 13, 2005, The City Of Tampa Wastewater Department

Reports

The Bay Study Group (BSG) conducted nutrient enrichment studies (bioassays) on natural phytoplankton population samples collected at four locations in the Lower Hillsborough River on October 10, 2005. Test site HR1 was located approximately 320m upriver of the Rowlett Park Blvd. bridge (Lat: 28o 01.368’N; Lon: 82o 25.914’W), test site HR2 was located approximately 200m upriver of the Nebraska Ave. bridge (Lat: 28o 01.174’N; Lon: 82o 26.960’W), test site HR3 was located approximately 280m downriver of the Florida Ave. bridge (Lat: 28o 01.257’N; Lon: 82o 27.740’W), and test site HR4 was located approximately 20m upriver of the Sligh Ave. bridge …

Systematic Revision Of The Genus Eupleura H. And A. Adams, 1853 (Gastropoda: Muricidae) In The Neogene To Recent Of Tropical America, Gregory S. Herbert

School of Geosciences Faculty and Staff Publications

The systematics of the Neogene to Recent genus Eupleura of tropical America are revised, with descriptions of four new species: Eupleura engerrabunda, from the Late Miocene of Mexico (Atlantic); Eupleura gravidentata, from the Plio-Pleistocene of Colombia (Atlantic); Eupleura paroudia, from the Early or middle Pliocene of Mexico (Atlantic); and Eupleura vokesorum, from the Pliocene of Costa Rica (Pacific) and Ecuador and the Recent tropical eastern Pacific. Two recent taxa, Eupleura plicata and Eupleura limata, are also resurrected, increasing the standing diversity of Eupleura in the eastern Pacific to seven species. Eupleura limata, however, may …

Geodetic Gps Measurements In South Iceland: Strain Accumulation And Partitioning In A Propagating Ridge System, P. C. Lafemina, Timothy H. Dixon, R. Malservisi, T. Arnadottir, E. Sturkell, F. Sigmundsson, P. Einarsson

School of Geosciences Faculty and Staff Publications

GPS observations in south Iceland between 1994 and 2003 are compared with two-dimensional elastic half-space and viscoelastic coupling models for two parallel rift zones, representing the Western and Eastern volcanic zones (WVZ, EVZ). GPS data from the Hreppar block, between the WVZ and EVZ, fit a rigid block model within uncertainties. Spreading rates across the WVZ increase from 2.6 ± 0.9 mm/yr in the northeast to 7.0 ± 0.4 mm/yr in the southwest. Conversely, spreading rates in the EVZ decrease from 19.0 ± 2.0 mm/yr in the northeast to 11.0 ± 0.8 mm/yr in the southwest, the direction of ridge …

Data Summary From The Tampa Bay Interagency Seagrass Monitoring Program Through Year 2004, Walt Avery, Roger Johansson

Reports

Results regarding seagrass species abundance, distribution, and zonation over time are presented for the 1997-2004 period in Hillsborough Bay (HB, Figures 16-27) and the 1998-2004 period for Old Tampa Bay (OTB, Figures 3-14), Middle Tampa Bay (MTB, Figures 29-41), Lower Tampa Bay, including Terra Ceia Bay (LTB, Figures 43-57), and Boca Ciega Bay (BCB, Figures 59-69). For each transect, results are presented in a graphic format illustrating annual species composition, abundance, and distribution. Seagrass abundance is presented as percent coverage within a square meter using the Braun Blanquet coverage class system.

The 7 May 2001 Induced Seismic Event In The Ekofisk Oil Field, North Sea, L. Ottemöller, H. H. Nielsen, K. Atakan, Jochen Braunmiller, J. Havskov

School of Geosciences Faculty and Staff Publications

A moderate size seismic event on 7 May 2001 was strongly felt on platforms in the Ekofisk oil field, in the southern North Sea, but did not cause damage to platforms or wells. We combined near- and far-field observations to develop a consistent source model and to determine whether the event was induced. Seismic data placed the epicenter inside the Ekofisk field and suggested a shallow source depth based on spectral and moment tensor analysis. GPS data from the Ekofisk platforms displayed permanent vertical and horizontal movement due to the event. A topographic bulge in the sea bottom, revealed by …

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 …

Biomass Shifts In Phytoplankton, Macroalgae And Seagrass With Reduced Nitrogen Loading Rates To Hillsborough Bay, J.O. R. Johansson

Reports

Presentation on Biomass Shifts In Phytoplankton, Macroalgae And Seagrass With Reduced Nitrogen Loading Rates To Hillsborough Bay.

Degassing And Hydrothermal Activity At Mt. Spurr, Alaska During The Summer Of 2004 Inferred From The Complex Frequencies Of Long-Period Events, S. De Angelis, Stephen R. Mcnutt

School of Geosciences Faculty and Staff Publications

Results of analyses of unusual long-period earthquakes, recorded between July and September 2004 at Mt. Spurr, Alaska, are presented. The waveforms of these events are characterized by quasi-sinusoidal signatures of long duration (up to 40 sec) with slowly decaying amplitudes; bandwidths of 0.5–4.0 Hz are typical; amplitude spectra are marked by strong and sharp peaks, reflecting the quasi-monochromatic nature of the signal. The temporal variations of the complex frequencies are investigated by use of the Sompi method; the dominant mode is resolved and its Q factor estimated for each available event. Dominant frequencies are found in the band 0.8–2.2 Hz …

Hydrology Of Vernal Pools At Three Sites, Southern Sacramento Valley, Robert J. Williamson, Graham E. Fogg, Mark C. Rains, Thomas H. Harter

School of Geosciences Faculty and Staff Publications

The subsurface hydrology of vernal pools at three vernal pool complexes was investigated during three wet seasons in 2002-2004. The complexes were at Gridley Ranch, Valensin Ranch, and the Mather Field in northern California. The selected complexes provided variation in soils, landforms and topography. Three vernal pools were chosen in each complex based on variation in pool type, size, and position in the drainage system. The objectives were to describe the subsurface hydrology of vernal pools to refine the conceptual model of vernal pool hydrology and to answer questions about: the size of watershed support for vernal pools, the importance …

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

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

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 …

Summary Of Nutrient Enrichment Studies Of Natural Phytoplankton Populations In The Lower Hillsborough River And The Palm River Conducted On February 1 - 4, 2005, The City Of Tampa Wastewater Department

Reports

The Bay Study Group (BSG) conducted nutrient enrichment studies (bioassays) on natural phytoplankton population samples collected in the lower Hillsborough River and the Palm River on February 1, 2005. The Hillsborough River test site was located approximately 200m upriver of the Nebraska Avenue bridge (Lat: 28o 01.171’N; Lon: 82o 27.025’W) and the Palm River test site was located approximately 300m downstream from the barrier at Structure-160 (Lat: 27o 57.308’N; Lon: 82o 22.200’W).

Summary Of Nutrient Enrichment Studies Of Natural Phytoplankton Populations In The Lower Hillsborough River, The Palm River, And The Alafia River Conducted On October 18 - 22, 2004, The City Of Tampa Wastewater Department

Reports

The Bay Study Group (BSG) conducted nutrient enrichment studies (bioassays) on natural phytoplankton population samples collected in the Lower Hillsborough River, the Palm River, and the Alafia River on October 18, 2004. The Lower Hillsborough River test site was located approximately 200m upriver of the Nebraska Avenue bridge (Lat: 28o 01.171’N; Lon: 82o 27.025’W), the Palm River test site was located approximately 300m downstream from the barrier at Structure-160 (Lat: 27o 57.308’N; Lon: 82o 22.200’W), and the Alafia River test site was located at the Hillsborough County boat ramp at Center Avenue (Lat: 27o 52.842’N; Lon: 82o 18.011’W).

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 …

Momentum Balance Diagnoses For The West Florida Shelf, Yonggang Liu, Robert H. Weisberg

Yonggang Liu

The momentum balance over the West Florida Shelf is diagnosed using observations of currents, bottom pressures, temperatures, winds, and coastal sea levels, along with hydrographic data from 32 monthly cruises spanning summer 1998 to winter 2001. Over synoptic weather time scales, the depth-averaged across-shelf momentum balance on the inner shelf is essentially geostrophic with smaller contributions from the across-shelf wind stress and other terms. Coherence analyses show that 95% of the acceleration (Coriolis and local) variance may be accounted for by the pressure gradient and friction (surface and bottom) over the synoptic weather band. The balances are more complicated on …

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 …

The 2003 Boumerdes, Algeria Earthquake: Regional Moment Tensor Analysis, Jochen Braunmiller, Fabrizio Bernardi

School of Geosciences Faculty and Staff Publications

We used regional broadband seismograms to determine seismic moment tensors for the destructive May 21, 2003 Boumerdes (Algeria) M_w = 7.0 earthquake and its larger aftershocks. Fully automatic inversions using near-real time data provided solutions for seven M_w ≥ 4.7 events within 90 minutes after event occurrence. After adding off-line data, we manually obtained 30 solutions (M_w ≥ 3.8) from May 2003 to January 2004. All have shallow source depths (6–21 km). The median P-axis orientation (338°) of 24 thrust and four strike-slip events is consistent with Africa-Eurasia plate motion (330°). The main shock hypocenter at 8–10 …

Numerical Simulation Of Double‐Diffusive Finger Convection, Joseph D. Hughes, Ward E. Sanford, H. L. Vacher

School of Geosciences Faculty and Staff Publications

A hybrid finite element, integrated finite difference numerical model is developed for the simulation of double‐diffusive and multicomponent flow in two and three dimensions. The model is based on a multidimensional, density‐dependent, saturated‐unsaturated transport model (SUTRA), which uses one governing equation for fluid flow and another for solute transport. The solute‐transport equation is applied sequentially to each simulated species. Density coupling of the flow and solute‐transport equations is accounted for and handled using a sequential implicit Picard iterative scheme. High‐resolution data from a double‐diffusive Hele‐Shaw experiment, initially in a density‐stable configuration, is used to verify the numerical model. The temporal …

Assembly Focuses On Volcanism And Societal Impacts, Anita Grunder, Stephen R. Mcnutt

School of Geosciences Faculty and Staff Publications

With a theme of “Volcanism and Its Impact on Society,” the November 2004 meeting of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) held in Pucón, Chile, brought together experts to discuss many aspects of volcanology.

The five‐day IAVCEI meeting was the association's largest, attracting 940 participants from 44 countries. U.S. participants constituted one third. The meeting consisted of over 1100 abstracts presented in 12 theme sessions, and reflected a diversity of disciplines and techniques encompassed by volcanic studies.

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 …

A Disturbance Instance For Karst Environments., Philip Van Beynen, Kaya Van Beynen

USF St. Petersburg campus Faculty Publications

Karst environments, unique from other environments, require their own disturbance index. Karst resources are increasingly disturbed by a variety of processes related to social, physical, and economic factors. Recent studies have begun to qualify and quantify these disturbances, yet their focus has been limited to one or two factors such as biotic, geomorphic, or economic impacts. A more holistic approach, addressing economic, scientific, and cultural factors, is needed, to effectively assess the threats to karst areas. Currently, there is no efficient method to measure, compare, and contrast the disturbance of karst environments. We propose a hierarchal and standardized environmental disturbance …

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

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

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

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

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

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 …