Earth Sciences Commons^™

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.

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 …

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.

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 …

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.

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 …

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 …

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.

Locating A Radioactive Waste Repository In The Ring Of Fire, Mick Apted, Kelvin Berryman, Neil Chapman, Mark Cloos, Charles B. Connor, Kazumi Kitayama, Steve Sparks, Hiroyuki Tsuchi

School of Geosciences Faculty and Staff Publications

The scientific, technical, and sociopolitical challenges of finding a secure site for a geological repository for radioactive wastes have created a long and stony path for many countries. Japan carried out many years of research and development before taking its first steps in site selection.

The Nuclear Waste Management Organization of Japan (NUMO) began looking for a high-level waste repository site (HLW, vitrified residue from reprocessing power reactor fuel) 2 years ago. Over the next 10–20 years, NUMO hopes to find a site to dispose of ∼20,000 tons of HLW in a robustly engineered repository constructed at a depth of …

Geodetic And Sconstraints On Some Seismogenic Zone Processes In Costa Rica, Edmundo Norabuena, Timothy H. Dixon, Susan Schwartz, Heather Deshon, Andrew Newman, Marino Protti, Victor Gonzalez, Leroy Dorman, Ernst R. Flueh, Paul Lundgren, Fred Pollitz, Dan Sampson

School of Geosciences Faculty and Staff Publications

New seismic and geodetic data from Costa Rica provide insight into seismogenic zone processes in Central America, where the Cocos and Caribbean plates converge. Seismic data are from combined land and ocean bottom deployments in the Nicoya peninsula in northern Costa Rica and near the Osa peninsula in southern Costa Rica. In Nicoya, inversion of GPS data suggests two locked patches centered at 14 ± 2 and 39 ± 6 km depth. Interplate microseismicity is concentrated in the more freely slipping intermediate zone, suggesting that small interseismic earthquakes may not accurately outline the updip limit of the seismogenic zone, the …

Modeling Long-Term Volcanic Hazards Through Bayesian Inference: An Example From The Tohoku Volcanic Arc, Japan, Andrew J. Martin, Koji Umeda, Charles B. Connor, Jennifer N. Weller, Dapeng Zhao, Masaki Takahashi

Geology Faculty Publications

The need to quantitatively estimate future locations of volcanoes in the long-term is of increasing importance, partly as a result of the requirement of constructing certain types of installations in regions of low geologic risk. The complex geological factors and natural processes controlling the locations of volcanoes make it problematic to estimate future patterns deterministically. Instead, the probabilistic approach can be developed with quite high levels of confidence; however, for regions with few or no volcanoes, there is a need to include additional geological and geophysical data that may indicate the likelihood of future volcanism. We achieve this using Bayesian …

Lithium Abundance And Isotope Systematics Of Forearc Serpentinites, Conical Seamount, Mariana Forearc: Insights Into The Mechanics Of Slab-Mantle Exchange During Subduction, Laurie D. Benton, Jeffrey G. Ryan, Ivan P. Savov

Geology Faculty Publications

[1] Variable lithium contents and contrasting Li isotopic signatures are evident in the serpentininite muds and clasts extruded at Conical Seamount in the Mariana forearc. The muds have high Li contents compared to mantle values (3–7 ppm) and a mean δ7Li value of ∼+6‰. The clasts are generally lower in Li, and δ7Li varies from −6‰ to +10‰, with higher δ7Li correlating broadly to higher lithium contents. The diverse δ7Li in the serpentinite clasts suggests Li exchanges between mantle rocks and evolving slab‐derived fluids from different depths, producing a subarc mantle that is zoned in terms of Li abundances and …

Space-Based Measurements Of Sheet Flow Characteristics In The Everglades, Wetland, Florida, Shimon Wdowinski, Falk Amelung, Fernando Miralles-Wilhelm, Timothy H. Dixon, Richard Carande

School of Geosciences Faculty and Staff Publications

New space-based observations of South Florida with interferometric SAR (InSAR) reveal spatially detailed, quantitative images of water levels in the Everglades. The new data capture dynamic water level topography, providing the first detailed picture of wetland sheet flow. We observe localized radial sheet flow in addition to well-known southward unidirectional sheet flow, modelled as a linear diffusive flow. We obtain quantitative estimates of flow diffusivity (23–91 m²/s), the first space-based estimates of such hydrologic parameter for the Everglades. Space-based hydrologic observations can provide critical information for monitoring, understanding and managing wetland sheet flow, and contribute to wetland restoration.

“Coupling” Semantics And Science In Earthquake Research, Kelin Wang, Timothy H. Dixon

School of Geosciences Faculty and Staff Publications

Coupling is a convenient word that describes a wide variety of interactions or feedback processes, including those that we do not fully understand. Examples in Earth science include ocean-atmosphere coupling, climate-tectonics coupling, and core-mantle coupling. The word is also very popular in discussions of plate boundary earthquake processes.

As a vague expression, fault coupling is a perfectly adequate term, describing some kind of mechanical interaction between rocks of each side of a fault. For those of us who try to infer fault processes from geodetic measurements, coupling usually indicates a state of no or low current slip. If a fault …

Simulated Changes In Shallow Groundwater And Vegetation Distributions Under Different Reservoir Operations Scenarios, Mark Cable Rains, Jeffery F. Mount, Eric W. Larsen

Geology Faculty Publications

The objectives of this study were to develop and use a linked groundwater and vegetation model to simulate groundwater and vegetation distributions in a riverine and reservoir-fringe system under different reservoir operations scenarios. This study was conducted where Little Stony Creek flows into East Park Reservoir on the east front of the Coast Range, northern California. A numerical groundwater model was used to model mean depth to groundwater during the growing season for water years 1980–1999 for each of five community types identified on the study site. Multiple vegetation models were developed, each of which described the probability that a …

Activators Of Luminescence In Speleothems As Source Of Major Mistakes In Interpretation Of Luminescent Paleoclimatic Records, Y. Y. Shopov

International Journal of Speleology

This work summarizes the main results of the operation of the International Program “Luminescence of Cave Minerals” of the commission on Physical Chemistry and Hydrogeology of Karst of UIS of UNESCO in the field of activators of speleothem luminescence. It discusses Activators of Luminescence in Speleothems as a source of major mistakes in the interpretation of luminescent paleoclimatic records. It demonstrates the existence of 6 types of luminescence of speleothems and cave minerals in dependence of the type of the luminescence center and its incorporation in the mineral. 24 different activators of photoluminescence of speleothem calcite and 11 of aragonite …

Trace Elements In Speleothems. A Short Review Of The State Of The Art, Sophie Verheyden

International Journal of Speleology

A state of the art of the research on trace elements of speleothems is given. First studies focussed on problems such as the colour of speleothems and the aragonite problem. Insitu studies and studies oriented towards a better understanding of vadose hydrology brought new insights in the controls on trace elemental composition of speleothems. Recent studies deal with microscale analyses and annual and intra-annual chemistry changes. Further in-situ studies should be performed to further differentiate influences, such as climate, soil/weathering and local hydrology in order to better constrain possible transfer functions between the surface and a speleothem.

Influence Of Solar Luminosity Over Geomagnetic And Climatic Cycles As Derived From Speleothems, Y. Shopov, D. Stoykova, L. Tsankov, M. Sanabria, D. Georgieva, D. Ford, L. Georgiev

International Journal of Speleology

We observed cycles presented in a luminescent solar insolation proxy record from a speleothem from Jewel Cave, South Dakota, US. We found cycles of orbital precession with periods of 23 and 19 ka and of obliquity of 41 ka and many others from non-orbital origin in this sample. We determined the Solar origin of the cycles with durations of 11500, 4400, 3950, 2770, 2500, 2090, 1960, 1670, 1460, 1280, 1195, 1145, 1034, 935, 835, 750 and 610 years. It was done by their detection both in proxy records of speleothem luminescence, Δ¹⁴C and the intensity of the geomagnetic …

Surface Cover Infiltration Index: A Suggested Method To Assess Infiltration Capacity For Intrinsic Vulnerability In Karstic Areas In Absence Of Quantitative Data, Levent Tezcan, Mehmet Ekmekci

International Journal of Speleology

Karst is a hydrogeological environment of importance not only for its water resources potential but also for its scenic and economic potential, thereby increasing the intensity of human impact. The uniqueness of karst in this regard stems from its high sensitivity and vulnerability to imposed pressures and its distinctive response to these pressures. Therefore, a clear definition and formulation of the concept of ‘intrinsic vulnerability’ is essential for the design of vulnerability and/or management criteria of the karstic system as a resource. In this regard, the recharge rate, the amount of water passing through the unsaturated zone into the aquifer, …

Dissaggregation Modelling Of Spring Discharges, Elena Kirilova Bojilova

International Journal of Speleology

Disaggregation models are basically divided into three main groups: temporal, spatial and temporal-spatial. The focus of this paper is the application of temporal disaggregation models to disaggregate the seasonal flow in some large time intervals to sub-seasonal flows in some shorter time intervals. Two basic models are applied: the original model of Mejia and Rousselle and the corrected extended Lin model one-stage disaggregation. The flow totals from some karstic springs are used. Data for five springs in different areas of Bulgaria for the aims of the study are executed. The synthetic data generation for the chosen spring stations for a …

Comparative Estimate Of Resistance To Drought For Selected Karstic Aquifers In Bulgaria, Tatiana Orehova

International Journal of Speleology

Effective management of water resources requires adequate knowledge of groundwater system including the influence of climate variability and climate change. The drought of 1982-1994 in Bulgaria has led to important decrease of springflow and lowering of water levels. Therefore, groundwater demonstrated its vulnerability to drought. The purpose of this paper is to determine relative resistance of selected aquifers in Bulgaria to a prolonged decrease of recharge to groundwater. The drought resistance indicator has been defined for some karstic aquifers based on the method proposed in report of BRGM. The data from National Hydrogeological Network located in the National Institute of …

Paleocollapse Structures As Geological Record For Reconstruction Of Past Karst Processes During The Upper Miocene Of Mallorca Island, P. A. Robledo Ardila, J. J. Durán, L. Pomar

International Journal of Speleology

Paleocollapse structures and collapse breccias are one of the major features for paleokarst analysis and paleoclimate record. These are affecting the Llucmajor and Santanyí carbonate platforms. These platforms, of southern and eastern Mallorca respectively, are a good example of progradation reef platform in the western Mediterranean. The Santanyí platform is constituted of two sedimentary units, both affected by paleocollapse structures: (1) The Reef Complex attributed to the upper Tortonian-lower Messinian; (2) Santanyí Limestone attributed to the Messinian. There are abundant paleocollapse outcropping in the Reef Complex and Santanyí Limestone units. These structures have been produced by roof collapse of caverns …

20 Years Of Speleothem Paleoluminescence Records Of Environmental Changes: An Overview, Yavor Y. Shopov

International Journal of Speleology

This paper discusses advance of the research on Speleothem Paleoluminescence Records of Environmental Changes after it have been first introduced by the author 20 years ago. It is demonstrated that most of the progress in this field was made in result of the operation of the International Program “Luminescence of Cave Minerals” of the commission on Physical Chemistry and Hydrogeology of Karst of UIS of UNESCO. Potential, resolution and limitations of high resolution luminescence speleothem proxy records of Paleotemperature, Solar Insolation, Solar Luminosity, Glaciations, Sea Level advances, Past Precipitation, Plants Populations, Paleosoils, Past Karst Denudation, Chemical Pollution, Geomagnetic field and …

The Distribution Of Radon Concentration In Caves, Arrigo A. Cigna

International Journal of Speleology

Radon concentration in caves is known to vary within an extremely wide range. Here the distribution of the average values of radon concentration is examined and a power law describing is identified, i.e. radon concentration has a fractal dimension D=1.26. This fact means that concentrations are not grouped around a mean value, a characteristic common to many other phenomena.

Evolution Of Golpazari-Huyuk Karst System (Bilecik-Turkey): Indications Of Morpho-Tectonic Controls, Mehmet Ekmekci, Lütfü Nazik

International Journal of Speleology

The Golpazari-Huyuk karst system is located in the Central Sakarya Basin whose geomorphologic evolution is mainly controlled by the Post-Miocene epirogenic continental rise. Drastic change in the drainage pattern and dissection of the carbonate platform were the major consequences of this tectonic movement. Rapid incision of the Sakarya river changed the position of the erosion base which consequently distorted the direction of surface and subsurface flow. The Golpazari and Huyuk plains are two topographically distinct, flat bottomed geomorphic features separated by a carbonate rock relief. The difference in elevation between these 10 km distant plains is 350 m. Morphological, geological …

Cave Temperatures And Global Climatic Change, Giovanni Badino

International Journal of Speleology

The physical processes that establish the cave temperature are briefly discussed, showing that cave temperature is generally strictly connected with the external climate. The Global Climatic changes can then influence also the underground climate. It is shown that the mountain thermal inertia causes a delay between the two climates and then a thermal unbalance between the cave and the atmosphere. As a consequence there is a net energy flux from the atmosphere to the mountain, larger than the geothermal one, which is deposited mainly in the epidermal parts of caves.

The Role Of The Environmental Archaeologist In The Study And Reconstruction Of Cave Palaeoclimate, Maria Gkioni

International Journal of Speleology

Man and environment are engaged in a continuous battle to impose themselves on one another. The results are found in environmental modifications or climatic oscillations and, as far as man is concerned, in the different character of cultural remains. Man responds to environmental changes by migrating or evolving technological innovations, both of which leave important remains that the archaeologist is called on to recognise and interpret during and after an excavation. They both also reflect the sociocultural responses to climatic stress. This paper refers to a specific case study, caves, which housed man and his activities from the very early …

Using Spreadsheets In Geoscience Education: Survey And Annotated Bibliography Of Articles In The Journal Of Geoscience Education Through 2003, Beth Fratesi, H. L. Vacher

School of Geosciences Faculty and Staff Publications

Thirty-eight papers published in the Journal of Geoscience Education ( JGE) from 1989 through 2003 explicitly use or recommend the use of spreadsheets as part of classroom or field exercises, projects, or entire courses. Many of the papers include the spreadsheets, and some include the equations. The papers demonstrate how spreadsheets allow students to explore a subject through problem-oriented, interactive, and quantitative exercises. We provide an annotated bibliography and classify the 38 JGE papers by spreadsheet use, mathematics skill area, and geologic subdiscipline. Our discussion of five selected articles — abundance of elements in the Earth’s crust; directional properties of …

Seismogenic Zone Structure Of The Southern Middle America Trench, Costa Rica, H. R. Deshon, S. Y. Schwartz, S. L. Bilek, L. M. Dorman, V. Gonzalez, J. M. Protti, E. R. Flueh, Timothy H. Dixon

School of Geosciences Faculty and Staff Publications

The shallow seismogenic portion of subduction zones generates damaging large and great earthquakes. This study provides structural constraints on the seismogenic zone of the Middle America Trench offshore central Costa Rica and insights into the physical and mechanical characteristics controlling seismogenesis. We have located ∼300 events that occurred following the M_W 6.9, 20 August 1999, Quepos, Costa Rica, underthrusting earthquake using a three-dimensional velocity model and arrival time data recorded by a temporary local network of land and ocean bottom seismometers. We use aftershock locations to define the geometry and characteristics of the seismogenic zone in this region. These …

Fault Creep And Microseismicity On The Hayward Fault, California: Implications For Asperity Size, Christina R. Gans, Kevin P. Furlong, Rocco Malservisi

School of Geosciences Faculty and Staff Publications

The Hayward fault is documented to undergo significant creep, with some patches accommodating 50% or more of the long‐term fault displacement. In spite of this, the fault has also experienced moderate to large earthquakes. By comparing the patterns of microseismicity observed on the fault with models of fault zone creep, we can investigate the long‐term displacement/deformation history of the fault in terms of the relative roles of aseismic creep, fault slip accommodated through microseismicity, and strain accumulation (slip deficit). We find that microseismicity on the Hayward fault produces a negligible percentage of the seismic moment dissipated on the fault. Combining …