Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer in south-central Texas and the Upper Floridan aquifer in western Florida, were investigated to assess factors that control the movement of contaminants to public-supply wells (PSWs). The geoche...

The Nubian Sandstone complex in the western desert is a part of the major regional Nubian aquifer system comprising West Africa. The different rock strata deposited in localities forming the units of the aquifer system. Farafra Oasis lies in the northern part of the Dakhla basin. In its southern region, the Nubian Sandstone (deep aquifer) is overlained by Dakhla shale but in the central and nor...

Aquitards are capable of generating and preserving large amounts of chemicals. The release of the chemicals from the aquitards poses a potential contamination risk to groundwater that may be used as a drinking water source. This work aimed to identify the contribution of hydrogeochemical processes in the aquitards to groundwater hydrochemistry in the underlying confined basal aquifer by studyin...

Mean groundwater levels of a multi-layered coastal leaky aquifer system are considered. The system consists of an unconfined aquifer, a confined aquifer and a semi-permeable layer between them. Both exact asymptotic solutions and approximate perturbation solutions are derived for multi-sinusoidal-component sea tide. At inland places far from the coastline, the perturbation solutions show a good...

As águas subterrâneas desempenham um papel essencial no ciclo hidrológico da região amazônica, constituindo uma reserva significativa de água alta qualidade, utilizável para diversos fins. No entanto, dados hidrogeológicos na são ainda escassos, com estudos concentrados particularmente em centros mais urbanizados. Na Província Petrolífera Urucu, município Coari/AM, onde está instalada a Base Op...

We analyzed seismicity linked to the 2014 phreatic eruption of Mount Ontake, Japan, on 27 September 2014. We first relocated shallow volcano tectonic (VT) earthquakes and long-period (LP) events from August to September 2014. By applying a matched-filter technique to continuous waveforms using these relocated earthquakes, we detected numerous additional micro-earthquakes beneath the craters. Th...

The Pantanal of Nhecolândia, the world's largest and most diversified field of tropical lakes, comprises approximately 10,000 lakes, which cover an area of 24,000 km(2) and vary greatly in salinity, pH, alkalinity, colour, physiography and biological activity. The hyposaline lakes have variable pHs, low alkalinity, macrophytes and low phytoplankton densities. The saline lakes have pHs above 9 o...

BACKGROUND The Soufriere Hills, a stratovolcano on Montserrat, started erupting in July 1995, producing volcanic ash, both from dome collapse pyroclastic flows and phreatic explosions. The eruptions/ash resuspension result in high concentrations of suspended particulate matter in the atmosphere, which includes cristobalite, a mineral implicated in respiratory disorders. AIMS To conduct toxico...

This study presents an approach for obtaining limited sets of realizations of hydraulic conductivity (K) of multiple aquifers using simulated annealing (SA) simulation and spatial correlations among aquifers to simulate realizations of hydraulic heads and quantify their uncertainty in the Pingtung Plain, Taiwan. The proposed approach used the SA algorithm to generate large sets of natural logar...