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Objective: To investigate radon emanation in geothermal manifestations around Mount Tampomas, West Java, Indonesia, and assess radon concentrations in soil and water samples. Methods: Radon measurements were conducted using the Durridge Rad7 instrument, supplemented with a soil gas probe for in-situ soil radon measurements at a depth of 80 ​cm. In-situ water radon measurements were performed using the Rad Aqua instrument, while radon measurements for hot water samples were conducted separately. Radon measurements for hot water samples were corrected for decay using a radon decay correction factor. Results: The analysis of radon measurements revealed a wide range of concentrations in soil and water samples. Soil radon concentrations ranged from 15 Bq/m³ to 4,660 Bq/m³, with localized hotspots exhibiting exceptionally high concentrations. Water radon measurements showed elevated levels, ranging from 0.2 Bq/L to 13.4 Bq/L in-situ, particularly in hot springs. In collected water samples, radon concentrations ranged from 1 Bq/L to 6 Bq/L. These combined results highlight significant variability in radon levels across different water sources influenced by geothermal activity. Conclusions: These findings indicate active emanation processes influenced by geological factors and underscore the role of subsurface geology and aquifer characteristics in radon transport mechanisms. The presence of localized radon hotspots suggests the need for comprehensive monitoring and proactive management strategies to mitigate environmental and public health risks associated with radon exposure.

Different empirical formulas have been proposed to describe the water retention curve (WRC) and relative permeability ([k.sub.r]) of soils. This paper presents a Bayesian framework that evaluates not only the [...]

Experiments were undertaken to study the soil-water characteristics of compacted sandy soil (SS) and cemented soil (CS) in field and laboratory conditions. The influence of vegetation and material density on the development of negative pore-water pressure (PWP) and degree of saturation ([S.sub.r]) in the studied materials was investigated. The field planting experiments demonstrated a promising survival rate of Schefflera heptaphylla in both types of material, while the (SS) promoted better growth of the seedlings than the cemented one. In the field study, PWP and [S.sub.r] of the compacted SS responded noticeably and promptly to natural drying-wetting cycles. However, the responses in the CS were relatively mild. When subjected to the same dryingwetting cycles, PWP responded more slowly and to a smaller magnitude compared with that of the uncemented counterpart. In addition, [S.sub.r] changed little in CS. An increase in the density of the SS promoted rapid development of negative PWP, while an opposite trend was observed for CS. Attempts have been made to explain the observations from the perspectives of material permeability and change in water content during a drying period in both soil types. Furthermore, in SS, the development of PWP (with a measurement limit of -90 kPa) was minimally affected by the presence of vegetation, while vegetation noticeably helped the development of negative PWP in CS. Bounds of the soil-water characteristic curve (SWCCs) of the studied materials were presented based on estimates from the drying and wetting scanning curves derived from the field monitoring. A corresponding laboratory study was carried out in an environmental chamber with controllable temperature and humidity. Monitoring results from the laboratory agreed qualitatively with those obtained from the field. Key words: evapotranspiration, sandy soil (SS), cemented soil (CS), soil-water characteristics, vegetation. Des experiences ont ete realisees pour etudier les caracteristiques de l'interaction sol-eau dans des sols sableux (SS) compactes et des sols consolides (SC), sur le terrain et en laboratoire. On a analyse l'influence de la vegetation et de la densite des materiaux sur l'augmentation de pression de l'eau interstitielle (PEI) negative et sur le degre de saturation ([S.sub.r]) dans les materiaux etudies. Les experiences de plantation sur le terrain ont mis en evidence un taux de survie prometteur de l'espece vegetale Schefflera heptaphylla dans deux types de materiaux, le sol sableux favorisant davantage la croissance des semis que le sol consolide. Dans l'etude realisee sur le terrain, la PEI et le [S.sub.r] du SS compacte a reagi de facon remarquable et rapidement aux cycles naturels d'humidification-assechement. Cependant, les reponses des SC ont ete relativement faibles. Lorsque ces derniers etaient soumis a des cycles d'humidification-assechement identiques, la PEI a varie plus lentement et avec une amplitude moins elevee que dans le cas des sols non consolides. En outre, [S.sub.r] a varie faiblement dans les SC. Une augmentation de la densite du SS a entraine une augmentation rapide de la PEI negative alors que le phenomene inverse a ete observe dans le SC. On a tente d'expliquer ces observations en se basant sur la permeabilite des materiaux et sur la variation de la teneur en eau durant une periode d'assechement dans le cas des deux types de sols. Par ailleurs, dans le SS, l'augmentation de la PEI (compte tenu d'une limite de mesure, egale -90 kPa) n'a ete affectee que de facon minime par la presence de vegetation. Cependant, cette derniere a beaucoup favorise l'augmentation de la PEI negative dans le SC. Les limites de la courbe caracteristique sol-eau des materiaux etudies ont ete decrites fi l'aide d'estimations issues des courbes de balayage d'assechement et d'humidification tracees fi partir des mesures effectuees regulierement sur le terrain. Une etude equivalente en laboratoire a ete realisee dans une chambre environnementale a temperature et humidite controlees. Les resultats des mesures regulieres effectuees en laboratoire coincidaient qualitativement avec celles obtenues sur le terrain. [Traduit par la Redaction] Mots-cles : evapotranspiration, sol sableux (SS), sol consolide (SC), caracteristique de l'interaction sol-eau, vegetation., Introduction Cemented soil (CS) is defined as a highly compacted mixture of soil, a measured amount of Portland cement, and water (ACI 2013). It is well known for its high [...]

One of the main concerns of deciphering tsunami sedimentary records along seashore is to link the emplaced layers with marine high energy events. Based on a combination of morphologic features, sedimentary figures, grain size characteristics, fossils content, microfossils assemblages, geochemical elements, heavy minerals presence; it is, in principle, possible to relate the sedimentary record to a tsunami event. However, experience shows that sometimes, in reason of a lack of any visible sedimentary features, it is hard to decide between a storm and a tsunami origin. To solve this issue, the authors have used the Anisotropy of Magnetic Susceptibility (AMS) to evidence the sediment fabric. The validity of the method for reconstructing flow direction has been proved when applied on sediments in the aftermath of a tsunami event, for which the behaviour was well documented (2004 IOT). We present herein an application of this method for a 56 cm thick paleo-deposit dated 4220 BP laying under the soil covered by the 2004 IOT, SE of Banda Aceh, North Sumatra. We analysed this homogenous deposit, lacking of any visible structure, using methods of classic sedimentology to confirm the occurrence of a high energy event. We then applied AMS technique that allowed the reconstruction of flow characteristics during sediment emplacement. We show that all the sequence was emplaced by uprush phases and that the local topography played a role on the re-orientation of a part of the uprush flow, creating strong reverse current. This particular behaviour was reported by eyewitnesses during the 2004 IOT event.

The maximum vertical uproot resistance ( P max ) of a plant can be used to indicate its stability. Attempts were made to predict the P max of a plant empirically from some of its size parameters. In practice, an infinite number of empirical models with different complexities can be formulated. This study presents a Bayesian model class selection method to evaluate the plausibility of each empirical model among a list of model candidates. The models were ranked to identify the most plausible one. A database of vertical uproot resistance of four shrubs and trees native to Hong Kong was first compiled by performing field uproot tests. The plant size parameters including height, basal diameter, canopy size, and above-ground dry weight, were measured before the uprooting. Second, the mathematical formulation of the Bayesian model class selection method was presented. Using this method the most plausible model for each studied species or plant type was identified. The uncertainty of the model coefficients and therefore the credibility of the predictions were quantified. The selected models were used to predict the P max of the studied plants in some additional tests. It was found that the P max of the studied species could be reliably predicted from the established simple empirical formulas containing only the height and/or basal diameter of the plant as the dependent variables. The study paves the way for nondestructive and reliable prediction of plant anchorage. [ABSTRACT FROM AUTHOR]