The present paper deals with a field experiments on evaporite rock samples and groundwater investigations in the Quinis test site, a hamlet of the Enemonzo municipality in NE Italy, were sinkholes ...occurred in the past and are still occurring causing severe damage to the existing infrastructures. The area is characterised by a Carnian evaporitic bedrock made of gypsum and anhydrite mantled by alluvial and colluvial deposits. In order to evaluate the loss of weight and volume of the subcropping evaporites as responsible for sinkholes, a field-experiment was carried out. Inside seven piezometers, at different depths, evaporitic rock samples were exposed to the naturally occurring variable climatic conditions such as degree of humidity, different air flow and hydrodynamic. The rock samples were installed at the beginning of April 2017 in the dry sections of piezometric tubes, in the vadose zone and in the phreatic zone. Data related to water level fluctuations were recorded by using data-logger devices and highlight significant changes in the water table. After 13 months of data recording (May 2018), rock samples were removed, reweighted and the volume loss measured. In addition, water from piezometer-experiment, representative of the groundwater circulation, were collected at different depths. The obtained results indicate that rock sample reduction is dependent on the hydrological regime and water chemistry and not on the number of days during which the samples remained submersed. In particular, the water geochemistry highlights the possible role in gypsum/anhydrite dissolution due to NaCl water admixing in a complex scenario. In additional, the geochemical data highlight the occurrence of some potentially toxic elements (As, Fe, Mn) at concentrations of concern in some water. This approach represents a novel contribution in the study of karst hazard in evaporites adding a tile to the knowledge of the fast evolutionary processes which cause sinkhole formation.
In a quickly changing environment where drinking water appears ever more scarce and polluted, it is vitally important to study the quantity and quality of the available resources. With this in mind, ...the Verzegnis mountain group (Western Carnian Prealps, NE Italy) represents an important karst aquifer system upon which to draw water to supply inhabitants and industrial activities. The aim of this study is to highlight the state of the art of the resources present in the hydrostructure, understanding the recharge areas and characterizing the flow dynamics with a view to a sustainable exploitation. To complete this study, classical field surveys were conducted during which the main geochemical characteristics were analyzed. Measurements of water temperature (T), Electrical Conductivity (EC), Total Dissolved Solid (TDS), groundwater discharge (Q) and precipitation amount were performed monthly for a period of two years. The geochemical characteristics were defined using water sample analyses of the major ions and δ
18
O values. The analyses performed and the resulting hydrogeological map allowed for a preliminary characterization of the hydrogeological behavior of the entire hydrostructure where the presence of tectonic structures and different lithological units represent a physical threshold for the waters. In fact, the groundwaters are mainly contained between the tectonic structure Douf—Auda thrust in the E, NE and a permeability threshold on the W created by the presence of the Dolomia di Forni Formation. In the southern side of the massif, a transcurrent fault creates a water divide between Mt. Verzegnis and Mt. Piombada.
Instrumenti, ki zvezno merijo nivo, temperaturo in prevodnost vode so bili postavljeni na 10 točkah. Opazovalna mesta so postavljena na dnu, kjer jama doseže vode Reke (Timave), ki zbira podzemne ...vode klasičnega Krasa. Predhodne analize velikega števila podatkov, ki smo jih zbrali do sedaj, pomagajo bolje določiti način pretakanja vode v globinah. Ugotovili smo tri različne vodne valove, vpliv črpanja na nekaterih delih in mešanje različnih voda na drugih. Some instruments that continuously measure height, temperature and conductivity of waters have been placed in 10 stations. The stations are located on the bottom of the cavities that reach the waters of the Timavo, the underground river that collects the hypogean waters of the Classical Karst. The preliminary analysis of the remarkable amount of data that has been collected up to now helps define the modalities of water circulation in depth better. There are three different types of flood wave, pumping effects in some tracts and mixing of different waters in other tracts.
Ob geoloških raziskavah vzdolž reke Karkheh, ki prereže gorsko verigo Zagrosa v zahodnem Iranu, je pritegnila pozornost avtorjev morfologija na evaporitih. V evaporitni formaciji Gachsaran so ločili ...tri tipe krasa, glede na njihovo lego vzdolž sinklinalne osi ali vzdolž krila gube. Vzdolž sinklinalne osi so vrtače, sufozijske vrtače, jame in udorne vrtače ter zmerno se spuščajoči jamski rovi na stiku apnenca in sadre, ki sledijo največjemu vpadu. Evaporite morphologies have attracted our attention during geological surveys on the Karkheh River, a water course that intersect the chain of the Mountains Zagros in the western Iran. We recognised three types of karst in the evaporitic Gachsaran Formation as a function of the localisation along the syncline axis or along a fold side. There are sinkholes and suffosion dolines or caves and collapse dolines along the syncline axis, gently dipping galleries at the contact between limestone and gypsum following maximum dip.
Evaporite karst in Italy: a review De Waele, Jo; Piccini, Leonardo; Columbu, Andrea ...
International journal of speleology,
05/2017, Letnik:
46, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Although outcropping rarely in Italy, evaporite (gypsum and anhydrite) karst has been described in detail since the early 20th century. Gypsum caves are now known from almost all Italian regions, but ...are mainly localised along the northern border of the Apennine chain (Emilia Romagna and Marche), Calabria, and Sicily, where the major outcrops occur. Recently, important caves have also been discovered in the underground gypsum mines in Piedmont. During the late 80s and 90s several multidisciplinary studies were carried out in many gypsum areas, resulting in a comprehensive overview, promoting further research in these special karst regions. More recent and detailed studies focused on the gypsum areas of Emilia-Romagna and Sicily. Sinkholes related to Permian-Triassic gypsum have been studied in Friuli Venezia Giulia. This article reviews the state of the art regarding different aspects of evaporite karst in Italy focusing on the main new results.
The new railway line between Divača and Koper/Capodistria in south-western Slovenia is being built, a part of which crosses the southern outskirts of the Classical Karst plateaux. It will run through ...two tunnels, the northern tunnel T1 (6.7 km long) and the southern T2 (6 km long), which partially cross karst aquifer system. A multi-tracer test with injections of fluorescent dyes uranine and naphthionate, bypassing the karst vadose zone, was carried out to define the directions and dynamics of the underground water flow. The main goals were better understanding of the complex hydrogeological conditions in the area and assessment of possible environmental impacts on the nearby water sources. With tracing of uranine injected into a nearby cave stream, the direction of flow from the northern T1 tunnel mainly towards the Reka-Timavo aquifer system and further towards the Timava/Timavo springs was proved. The peak velocities, as determined from the peaks of the tracer breakthrough curves, range from 29 m/h to 36 m/h. Through the wider and well-connected conduits of the Reka-Timavo system, the peak velocities can reach up to 88 m/h. The recovery of uranine in an intermediate cave, i.e., Jama 1 v Kanjaducah, amounted to approximately 74 %. The northern section of the southern T2 tunnel is a part of a wider bifurcation zone between the Osapska Reka and the Boljunec/Bagnoli springs, where peak flow velocities between 10 and 13 m/h have been determined by tracing of naphthionate injected into a borehole located in the line of the planned tunnel. It has been estimated that about 25 % of the injected naphthionate flew out through the Osapska Reka spring and about 5 % through the Boljunec/ Bagnoli springs. Based on this research, proper monitoring of any potential negative impacts of the new railway line will be made possible. The study presents an approach to better planning of hazard control of traffic routes in complex and highly karstified rock settings.
Fascinating and fragile environments as are the underground estuaries, need to be studied, understood and protected for present and future generations. Even if wide and abundant bibliography related ...to tides and their behaviour with respect to the external estuaries is available, none dealed with the estuary caves and the related hydrogeology. This paper aims to partially fill this gap presenting a preliminary study done at the Puerto Princesa Underground River (PPUR), in the Palawan Island (Philippines). The data was collected during the last expedition (November 2016) organised by La Venta, in which some of the authors took part. During the survey, the cave has been instrumented with in continuous diver data-logger devices (CTD) recording temperature (T), electrical conductivity (EC) and water level fluctuations. Longitudinal and vertical water hydrogeological profiles of the cave were realised with the aim of understanding the dynamics of the waters during different hydrogeological regimes in combination with salt water intrusion. In addition, a bathymetric profile was done to better identify the point where to realise the vertical logs. A significant rainstorm occurred during the expedition, lasting for approximately 12 hours resulting in 80 mm of rain, and its effects gave the researchers the opportunity to analyse the hydrodynamics of the flowing waters during a flood. In normal flow conditions, the longitudinal logs highlighted the presence of freshwater inlets and the vertical logs testified to a clear stratification of the waters (freshwaters at the surface and brackish waters at the bottom). During floods, the EC and T data showed evidence of a fast substitution of the resident waters. Key words: anchialine caves, sea water intrusion, hydrodynamics, karst springs, PPUR, Philippines. Učinek močnega naliva na hidrodinamiko podzemske reke Puerto princese (Palawan, Filipini) Očarljivo in občutljivo okolje, kot so podzemni estuariji, je treba preučevati, razumeti in zaščititi za sedanje in prihodnje generacije. Četudi imamo na voljo široko in bogato bibliografijo o plimovanju in delovanju plimovanja v zunanjih estuarijih, nobeno delo ne obravnava estuarskih jam in s tem povezane hidrogeologije. Namen tega članka je delno zapolniti to vrzel in predstaviti predhodno študijo na podzemni reki Puerto Princesa (PPUR) na otoku Palawan (Filipini). Podatki so bili zbrani med zadnjo ekspedicijo (novembra 2016), ki jo je organizirala La Venta, v kateri so sodelovali tudi nekateri avtorji. V raziskavi je bila jama opremljena z zveznimi merilci (CTD) temperature (T), električne prevodnosti (EC) in nihanja nivojev vode. Vzdolžni in navpični hidrogeološki vodni profili jame so bili izmerjeni, da bi razumeli dinamiko voda med različnimi hidrogeološkimi nivoji in med vdori morske vode. Poleg tega je bil opravljen tudi batimetrični profil, da bi lažje določili, kje izvesti navpične meritve. Med ekspedicijo se je zgodil močan naliv, ki je trajal približno 12 ur, padlo je 80 mm dežja, njegov učinek pa je raziskovalcem omogočil analizo hidrodinamike tekočih voda med poplavo. V običajnih vodostajih so vzdolžne meritve pokazale na dotoke sveže vode, vertikalne meritve pa so pokazale jasno stratifikacijo lastnosti vode (sveža voda na površini in brakična voda na dnu). Med poplavami so podatki EC in T potrdili hitro zamenjavo vode. Ključne besede: anhialine jame, vdor morske vode, hidrodinamika, kraški izviri, PPUR, Filipini.
In clinical practice, ultrasound standard planes (SPs) selection is experience-dependent and it suffers from inter-observer and intra-observer variability. Automatic recognition of SPs can help ...improve the quality of examinations and make the evaluations more objective. In this paper, we propose a method for the automatic identification of SPs, to be installed onboard a portable ultrasound system with limited computational power. The deep Learning methodology we design is based on the concept of Knowledge Distillation, transferring knowledge from a large and well-performing
teacher
to a smaller
student
architecture. To this purpose, we evaluate a set of different potential teachers and students, as well as alternative knowledge distillation techniques, to balance a trade-off between performances and architectural complexity. We report a thorough analysis of fetal ultrasound data, focusing on a benchmark dataset, to the best of our knowledge the only one available to date.
Graphical abstract
The significance of intra-mountain valleys to infrastructure and human settlements and the need to mitigate the geo-hazard affecting these assets are fundamental to the economy of Italian alpine ...regions. Therefore, there is a real need to recognize and assess possible geo-hazards affecting them. This study proposes the use of GIS-based analyses to construct a sinkhole susceptibility model based on conditioning factors such as land use, geomorphology, thickness of shallow deposits, distance to drainage network and distance to faults. Thirty-two models, applied to a test site (Enemonzo municipality, NE Italy), were produced using a method based on the Likelihood Ratio (λ) function, nine with only one variable and 23 applying different combinations. The sinkhole susceptibility model with the best forecast performance, with an Area Under the Prediction Rate Curve (AUPRC) of 0.88, was that combining the following parameters: Nearest Sinkhole Distance (NSD), land use and thickness of the surficial deposits. The introduction of NSD as a continuous variable in the computation represents an important upgrade in the prediction capability of the model. Additionally, the model was refined using a kernel density estimation that produced a significant improvement in the forecast performance.
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