MWH Global

Enviroscan Ukrainian Institute of Speleology and Karstology

Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 5
Community news

Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

Did you know?

That gradation is the leveling of a surface to a common level [16].?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms

Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 7
What is Karstbase?



Browse Speleogenesis Issues:

KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
See all featured articles from other geoscience journals

Search in KarstBase

Your search for resistivity (Keyword) returned 57 results for the whole karstbase:
Showing 46 to 57 of 57
Determining Geophysical Properties of a Near-Surface Cave through Integrated Microgravity Vertical Gradient and Electrical Resistivity Tomography, 2011,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Gambetta M. , Armadillo E. , Carmisciano C. , Stefanelli P. , Cocchi L. , Caratori Tontini F.

Vertical-gradient microgravity and electrical-resistivity tomography geophysical surveys were performed over a shallow cave in the Italian Armetta Mountain karst area, close to the Liguria-Piedmont watershed. The aim of this study was to test the geophysical response of a known shallow cave. The shallowest portion of the cave exhibits narrow passages and, at about 30 meters below the entrance, a fossil meander linking two large chambers, the target of the geophysical survey. The integrated results of the two surveys show a clear geophysical response to the cave. The surveys exhibited high resistivity values and a negative gravity anomaly over the large cave passages. This work confirms the ability of these geophysical techniques to give the precise location of the voids, even in complex environments. The application of these techniques can be successful for site surveying where the presence of hollows may be expected.

The Dead Sea sinkhole hazard: Geophysical assessment of salt dissolution and collapse, 2011,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Frumkin Amos, Ezersky Michael, Alzoubi Abdallah, Akkawi Emad, Abueladas Abdelrahman

A geophysical approach is presented for analyzing processes of subsurface salt dissolution and associated sinkhole hazard along the Dead Sea. The implemented methods include Seismic Refraction (SRFR), Transient Electromagnetic Method (TEM), Electric Resistivity Tomography (ERT), and Ground Penetration Radar (GPR). The combination of these methods allows the delineation of the salt layer boundaries, estimating its porosity distribution, finding cavities within the salt layer, and identifying deformations in the overlying sediments. This approach is shown to be useful for anticipating the occurrence of specific sinkholes, as demonstrated on both shores of the Dead Sea. These sinkholes are observed mainly along the edge of a salt layer deposited during the latest Pleistocene, when Lake Lisan receded to later become the Dead Sea. This salt layer is dissolved by aggressive water flowing from adjacent and underlying aquifers which drain to the Dead Sea. Sinkhole formation is accelerating today due to the rapid fall of the Dead Sea levels during the last 30 years, caused by anthropogenic use of its water.

Geophysics of Locating Karst and Caves, 2012,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Am Ende, Barbara Anne

Many solution cavities ranging from small voids to full-size caves have no entrances and therefore no access from the surface. Geophysical methods can be used, with varying degrees of reliability, to detect such cavities and can also provide information on the bedrock/regolith interface. These methods include microgravity, electrical resistivity, audio-magnetotelluric soundings, ground-penetrating radar, shallow seismic probes, synthetic aperture radar, and thermal probes. Magnetic induction (cave radio) can provide precise locations of underground passages if they have a surface access.

An electrical resistivity imaging-based strategy to enable site-scale planning over covered palaeokarst features in the Tournaisis area (Belgium), 2012,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Kaufmann O. , Deceuster J. , Quinif Y.

Since the beginning of the 20th century, more than 150 sinkhole occurrences, mainly dropout (or covercollapse)sinkholes, have been reported in the Tournaisis area (south-eastern Belgium). Land-use planning in such a context has to take into account hazards linked with sinkhole subsidence and collapse. Management maps, drawn at a regional scale, point out zones where karstic risks have to be taken into account when dealing with infrastructure or building projects. However, karst hazard is highly variable in three dimensions at the local scale. Therefore, for such purposes, an accurate methodology is needed to detect and delineate covered karst features, especially when located in urbanized areas. As geophysical investigations are sensitive to contrasts in physical properties of soils, these methods can be useful to detect such targets. The specific karstic context encountered in the Tournaisis area strongly guides the choice of investigation techniques. Electrical resistivity imaging (ERI) methods were tested on a wellknown site where dropout sinkholes occurred formerly. This site was also studied using static cone penetration tests (CPT) and boreholes. A 3D inverted resistivity model was computed based on the 2D ERI models obtained after inversion. Resistivity profiles were extracted at each CPT location and compared to geotechnical results to determine an empirical and site-specific resistivity law that allows discrimination between weathered zones and sound limestone. Performance tests were conducted to evaluate the potential of the proposed methodology for two typical engineering problems based on two current hypotheses. Borehole data were used as ground truth. Similar performance tests were also computed using the CPT depth to bedrock model. The results of these performance tests are compared and discussed. Finally, an ERI-based investigation strategy is proposed to assess karst hazard in palaeokarstic context, such as encountered in the Tournaisis area, at the scale needed for building and infrastructure purposes. 

2D and 3D imaging of the metamorphic carbonates at Omalos plateau/polje, Crete, Greece by employing independent and joint inversion on resistivity and seismic data, 2012,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Hamdan Hamdan, Economou Nikos, Kritikakis Giorgos, Andronikidis Nikos, Manoutsoglou Emmanuil, Vafidis Antonis, Pangratis Pangratis, Apostolidou Georgina

A geophysical survey carried out at Omalos plateau in Chania, Western Crete, Greece employed seismic as well as electrical tomography methods in order to image karstic structures and the metamorphic carbonates (Tripali unit and Plattenkalk group) which are covered by post-Mesozoic deposits (terra rossa, clays, sands and gravels). The geoelectrical sections image the metamorphic carbonates which exhibit a highly irregular relief. At the central part of the plateau the thickness of post-Mesozoic deposits (terra rossa, clays, sands and gravels) ranges from 40-130 m. A 3D resistivity image was generated by inverting resistivity data collected on a grid to the south west at the Omalos plateau. The 3D resistivity image delineated a karstic structure at a depth of 25 to 55 m. On the same grid the depth to the top of the karstified carbonates ranges from 25-70 m. This is also verified on the resistivity sections and seismic velocity sections along lines 5 and 7 of the above mentioned grid which are derived from the cross-gradients joint inversion.

Geoelectrical Characterization of Sulphate Rocks, 2012,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Guinea Maysounave, Ander

Gypsum rocks are widely exploited in the world as industrial minerals. The purity of the gypsum rocks (percentage in gypsum mineral –CaSO4•2H2O- in the whole rock) is a critical factor to evaluate the potential exploitability of a gypsum deposit. It is considered than purities higher than 80% in gypsum are required to be economically profitable. Gypsum deposits have been studied with geoelectrical methods; a direct relationship between the electrical resistivity values of the gypsum rocks and its lithological composition has been established, with the presence of lutites being the main controlling factor in the geoelectrical response of the deposit. This phenomenon has been quantified by means of a combination of theoretical calculations, laboratory measurements and field data acquisition. A geoelectrical classification of gypsum rocks defining three types of gypsum rocks has been elaborated. Anhydrite (CaSO4) is frequently found in gypsum quarries and in no-outcropping sulphates. Because of its highest hardness than gypsum it supposes a problem for the extraction of gypsum; the fronts of the quarries in which anhydrite is found are stopped at the moment when it appears. The electrical properties of calcium sulphates have been studied by means of geoelectrical methods. The conductivity of crystals has been tested in laboratory. A direct relationship between the electrical conductivity values of the calcium sulphate rocks and its lithological composition has been established being the lutitic matrix the main controlling factor when it is percolant (connected at long range). When the rock is matrix dominant, the electrical resistivity trend is bond to the Hashin-Shtrikman lower bound for multiphase systems. On the other hand, when the rock is calcium sulphate dominant the trend shows the one of the Hashin-Shtrikman upper bound. A geoelectrical classification for calcium sulphate rocks has been elaborated. With this classification it is possible to differentiate between calcium sulphate rocks with different composition according to their electrical resistivity value. Glauberite (Na2Ca(SO4)2) is nowadays exploited as industrial mineral. Glauberite rocks usually have high lutite content in their composition, together with other evaporictic minerals as gypsum, anhydrite or halite among others. There is no reference to the conductivity of glauberite rocks in the bibliography, but due to their impurity it is expected to observe values as the observed for other sulphates in the matrix domain (less than 55% in purity). Two areas of the Ebro river basin (the Zaragoza and La Rioja sectors) have been studied by means of electrical resistivity tomography profiles, in which glauberite has been found in boreholes. As example of application for the study of sulphate deposits, an electrical resistivity tomography survey has been carried out in the Pira Gypsum member (SE of Catalan margin of the Tertiary Ebro Basin, Spain). Additionally, a continuous coring drill was performed in order to support the study. Electrical imaging has been successfully applied to identify the gypsum deposits interlayered in lutite units. Another resistivity survey has been carried out in an active gypsum quarry in the Gelsa Gypsum unit (Zaragoza, N Spain). During the extraction of the rock, the most important parameters to know are the purity changes in the deposit. Sudden changes in the purity make the processing of the raw material less profitable. The performed profiles have shown different gypsum layers from which the purest layers have been identified. Electrical resistivity tomography lines are useful in prospection of gypsum deposits. However, electrical imaging prospection should be supported by an accurate petrological study of the deposits, in order to properly interpret the resistivity profiles.

Electrical resistivity surveys of anthropogenic karst phenomena, southeastern New Mexico, 2012,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Land L. , Veni G.

A small but significant number of sinkholes and other karst phenomena in southeastern New Mexico are of human origin and are often associated with solution mining of salt beds in the shallow subsurface. In 2008 two brine wells in a sparsely populated area of northern Eddy County, New Mexico, abruptly collapsed as a result of solution mining operations. The well operators had been injecting fresh water into underlying salt beds and pumping out brine for use as oil field drilling fluid. A third brine well within the city limits of Carlsbad, New Mexico, has been shut down to forestall possible sinkhole development in this more densely populated area. Electrical resistivity surveys conducted over the site of the brine well confirm the presence of a large, brine-filled cavity beneath the we0llhead. Laterally extensive zones of low resistivity beneath the well site represent either open cavities and conduits caused by solution mining or highly fractured and/or brecciated, brine-saturated intervals that may have formed by sagging and collapse into underlying cavities. The data also indicate that significant upward stoping has occurred into overlying strata.

Electrical Tomography Applied to the Detection of Subsurface Cavities, 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Martineslpez J. , Rey J. , Dueas J. , Hidalgo C. , Benavente J.

We have analyzed the geoelectric response produced by three cavities cut into different geological substrata of granite, phyllite, and sandstone that had previously been characterized by direct methods. We also examined a mining void excavated in granite. In each case, we applied three different geoelectric arrays (Wenner-Schlumberger, Wenner and dipole-dipole) and several inter-electrode spacings. The survey results suggest that electrical resistivity tomography is a viable geophysical tool for the detection and monitoring of mining voids and other subsurface cavities. The results vary depending on a wide range of factors, such as the depth and diameter of the cavity, the multi-electrode array used, the inter-electrode spacing, the geological model, and the density of the data. The resolution capacity of the Wenner- Schlumberger array for the detection of these cavities was greater than that of the Wenner array and slightly better than the dipole-dipole. There is a direct relationship between inter-electrode spacing and diameter of the cavity. In general, we observed a loss of resolution as the distance between the electrodes increased. The most efficient detection was achieved when the inter-electrodes distance was less than or equal to the diameter of the cavity itself. In addition, cavity detection became increasingly less precise with its depth beneath the surface. Cavities with a radius of about 1.5 m were located by both the Wenner- Schlumberger method and the dipole-dipole at depths of more than 4.6 m, which means that prospecting can be carried out at depths 3 times the radius of the cavity.

Karst Sinkholes Stability Assessment in Cheria Area, NE Algeria, 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Yacine Azizi, Med. Ridha Menani, Med Laid Hemila, Abderahmane Boumezbeur


Karst; Rock Mass Rating (RMR);Sinkhole collapse; Tebessa This research work deals with the problem of karst sinkhole collapse occurring in the last few years in Cheria area (NE Algeria). This newly revealed phenomenon is of a major constrain in land use planning and urbanization, it has become necessary to locate and assess the stability of these underground features before any planning operation. Several exploration methods for the localization of underground cavities have been considered. Geological survey, discontinuity analysis, resistivity survey [ground penetrating radar has not been used as most of the Mio-Plio-Quaternary filling deposit covering Eocene limestone contains clay layers which limits the applicability of the method (Roth et al. in Eng Geol 65:225–232, 2002)] and borehole drilling were undertaken in order to locate underground cavities and assess their depth, geometry, dimensions, etc. Laboratory testing and field work were also undertaken in order to determine both intact rock and rock mass properties. All the rock mechanics testing and measurement were undertaken according to the ISRM recommendations. It has been found that under imposed loading, the stability of the karst cavities depends on the geo-mechanical parameters (RMR, Rock Mass Rating; GSI, Geological Strength Index; E, Young modulus) of the host rock as well as the depth and dimensions of the gallery. It increases with RMR, GSI, E and depth and decreases as the cavity becomes wider. Furthermore, the calculation results show that a ratio (roof thickness to gallery width) of 0.3 and more indicate, a stable conditions. The results obtained in this work allow identifying and assessing the stability of underground karst cavities. The methodology followed in this paper can be taken as a road map in the establishment of a hazard map related to the studied phenomenon. This map will be a useful tool for the future urban extension planning in Cheria area.

Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Hunt B. B. , Smith B. A. , Adams M. T. , Hiers S. E. , Brown N.

Sudden cover-collapse sinkhole (doline) development is uncommon in the karstic Cretaceous-age Edwards limestone of central Texas. This paper presents a case-study of a sinkhole that formed within a stormwater retention pond (SWRP) in southwest Austin. Results presented include hydrogeologic characterizations, fate of stormwater, and mitigation of the sinkhole. On January 24, 2012, a 11 cm (4.5 in) rainfall filled the SWRP with about 3 m (10 ft) of stormwater. Subsequently, a sinkhole formed within the floor of a SWRP measuring about 9 m (30 ft) in diameter and 4 m (12 ft) deep. About 26.5 million liters (7 million gallons) of stormwater drained into the aquifer through this opening. To determine the path, velocity, and destination of stormwater entering the sinkhole a dye trace was conducted. Phloxine B was injected into the sinkhole on February 3, 2012. The dye was detected at one well and arrived at Barton Springs in less than 4 days for a minimum velocity of 2 km/day (1.3 mi/day).Review of pre-development 2-foot topographic contour and geologic maps reveals that the SWRP was built within a broad (5,200 m2; 6 acre), shallow depression bounded by two inferred NE-trending fault zones. Photographs taken during SWRP construction showed steep west-dipping bedrock in the northern SWRP wall. Following collapse of the sinkhole, additional hydrogeologic characterization included excavation to a depth of 6.4 m (21 ft), surface geophysics (resistivity), and rock coring. Geologic materials consisted mostly 89of friable, highly altered, clayey limestone consistent with epikarst in-filled with terra rosa providing a cover of the feature. Dipping beds, and fractured bedrock support proximity to the mapped fault zone. Geophysics and surface observations suggested a lateral pathway for stormwater flow at the junction between the wet pond’s impermeable geomembrane and compacted clay liner for the retention pond. The collapse appears to have been caused by stormwater down-washing poorly consolidated sediments from beneath the SWRP and into a pre-existing karst conduit system.

Mitigation of the sinkhole included backfill ranging from boulders to gravel, a geomembrane cover, and reinforced concrete cap. Additional improvements to the SWRP included a new compacted clay liner overlain by a geomembrane liner on the side slopes of the retention pond.

Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Gary M. O. , Rucker D. F. , Smith B. D. , Smith D. V. , Befus K.

Electrical and electromagnetic geophysical characterization is a proven tool for delineating obscured subterranean karstic features, such as caves, sinkholes, and solution enlarged fissures. Geophysical characterizations allow a wide range of deployment scales; airborne methods can accommodate a regional view on the order of kilometers, and ground-based methods can follow up with focused data on the order of meters. A helicopter frequency domain electro-magnetic (HFDEM) survey and ground-based direct-current electrical resistivity imaging (DC-ERI) geophysical studies at the Camp Bullis Military Training Site (Camp Bullis) in central Texas have been used to characterize permeability properties of the Edwards and Trinity Aquifers in the area. Results of three separate investigations identified zones of high density karst features and characterized specific karstic voids, including caves. In 2003, the USGS completed an HFDEM survey of Camp Bullis and nearby areas to map and image subsurface features related to the groundwater resources. The survey refined locations of mapped and previously unmapped faults and characterized the heterogeneity of the subsurface electrical signature. Karst mapping at Camp Bullis identified over 1500 features, and high density zones of features correspond with areas of high resistivity from the HEM data. DC-ERI surveys at several locations were used to infer and characterize known and hypothesized karst features. Site 8 suggests an inferred fault and 195dissolution feature. Two other sites were surveyed near major caves that directly recharge the Trinity Aquifer (indirectly to Edwards Aquifer) along Cibolo Creek. Integration of multi-scale geophysical datasets could be used to augment aquifer-wide recharge characterization and quantification.

Hidden sinkholes and karst cavities in the travertine plateau of a highly-populated geothermal seismic territory (Tivoli, central Italy), 2015,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943

Sinkholes and other karst structures in settled carbonate lands can be a significant source of hazard for humans and human works. Acque Albule, the study area of this work, is a Plio-Pleistocene basin near Rome, central Italy, superficially filled by a large and thick deposit of late Pleistocene thermogene travertine. Human activities blanket large portions of the flat territory covering most evidence from geological surface processes and potentially inducing scientists and public officials to underestimate some natural hazards including those connected with sinkholes. To contribute to the proper assessment of these hazards, a geomorphologic study of the basin was performed using digital elevation models (DEMs), recent aerial photographs, and field surveys. Historical material such as old aerial photographs and past geomorphologic studies both pre-dating the most part of quarrying and village building was also used together with memories of the elderly population. This preliminary study pointed out the presence of numerous potentially active sinkholes that are at present largely masked by either quarrying or overbuilding. Where this first study pointed out the apparent absence of sinkholes in areas characterized by high density of buildings, a detailed subsurface study was performed using properly-calibrated electrical resistivity tomography (ERT) and dynamic penetration measurements (DPSH), together with some borehole logs made available from the local municipality. This second study highlighted the presence of sinkholes and caves that are, this time, substantially hidden to the resolution of standard methods and materials such as aerial photographs, DEMs, and field surveys. Active sinkhole subsidence in the Acque Albule Basin may explain, at least in part, the frequent damages that affect numerous buildings in the area. The main conclusion from this study is that the mitigation of sinkhole hazard in highly populated areas has to pass through a thorough search of (hidden) sinkholes that can be masked by the Anthropocenic molding and blanketing of the territory. For these purposes, data from historical (pre-Anthropocene) documents as well as, where possible, subsurface investigations are fundamental.

Results 46 to 57 of 57
You probably didn't submit anything to search for