Temperature Of Hot Spring Research Articles

Applicability of Na/K geothermometer to the metapelitic non-volcanic geothermal fields in the Taiwan orogenic belt

Taiwan is situated at one of the world's most active orogenic belts with arc-continent collision. This event resulted in the burial and uplift of mudstones along the continental margin, transforming them into metapelitic mountains. These mountains intercept rainfall and serve as the driving force for deep water circulation, enabling meteoric fluids to carry residual heat to the surface, thus giving rise to hot springs. The Taiwan orogenic belt is home to over 100 hot springs, and some of the hot spring reservoir temperatures such as Chingshui, Tuchang-Jentse, Lushan, Chihpon, and Chinlun exceeds 160 °C. Geothermal development in Taiwan has been carried out in such hot spring areas without any volcanic activities.In order to assess reservoir temperatures and confirm the applicability of the Na/K geothermometer to such high temperature hot spring system, the concentrations of Na+, K+, and SiO2 were analyzed from geothermal wells. Considering the mineral composition of metapelitic host rock, a new Na/K geothermometer is proposed based on equilibrium between albite and illite:T>180∘C,T(∘C)=2474log(NaK)+3.73−273.15This formula is only applicable in a reducing fluid and does not involve the formation of clay minerals except illite. It also requires several years to reach equilibrium. When using this formula to estimate reservoir temperatures, careful consideration of various conditions is necessary. It is advisable to incorporate both quartz geothermometer and down-hole temperature measurements for a more accurate assessment. Combining the Na/K geothermometer with the quartz geothermometer, along with other geochemical data such as Cl−concentrations and δD and δ18O of fluid, helps to understand whether hydrothermal fluids have undergone evaporation, dilution, and/or mixing processes.

Sustainable wastewater recovery system employing geothermal energy – Performance and feasibility study

In this study, a sustainable wastewater recovery system employing geothermal energy has been proposed. The efficiency of the suggested sustainable system has been simulated using heat transfer. Then, component-wise validation has been carried out with the existing data available in the literature wherever applicable and estimated an error of ± 8 %. The proposed sustainable system’s parametric and performance analyses have employed the developed vapor. From the parametric study, it is observed that hot spring temperatures have a significant influence on sustainable systems. Further, through performance investigation, it is understood that low dam/river/sea water temperatures and enhancing the water condenser effectiveness and flow rate ratio simultaneously improve the system performance. For different climatic regions of India, explored the feasible geothermal hotspots near dams/rivers/seawater and analyzed that among the hot and dry, hot and humid, composite and cold regions, the proposed sustainable system is best suitable at a composite region with a maximum possible water extraction/freshwater generation rate of 0.78 L/h for the given specifications and operating range. Moreover, it is assessed that hot spring temperature is the deciding factor for sustainable system performance in different climatic regions. Further, the current study can be used as a reference for understanding the phenomenon of potential geothermal hotspots for wastewater recovery in various climatic areas

PENGGUNAAN SINAR INFRA MERAH UNTUK DETEKSI PANAS BUMI DAERAH SANGKANHURIP, KUNINGAN, JAWA BARAT

Geothermal resources can be explored with aerial photographs followed by surveys and analysis of geological, geochemical and geophysical data as well as shallow drilling. This research was conducted to determine the potential of geothermal resources using a camera capable of capturing infrared rays from objects and photo targets.Geothermal exploration is generally carried out with an initial survey using remote imagery and aerial photography techniques. Taking photos using a tool equipped with a Thermal Infrared Sensor (TIRS), namely a camera equipped with Forward Looking InfraRed (FLIR).The initial survey in this study was conducted at five locations of geothermal springs in the Sangkanhurip area, Kuningan, West Java. From these five locations using FLIR cameras detected geothermal resources with hot spring temperatures between 30 to 40 degrees Celsius.To find out the types of rocks that exist, a geological survey was carried out to make a geological map. The data and information obtained are then analyzed to obtain a map that displays geology with surface temperature data in the study area.This map can be utilized by companies interested in exploring and producing geothermal energy for use as a source of energy for Geothermal Power Generation (PLTP). Further analysis can be carried out with the Geochemical Method for predicting subsurface temperature. This discovery fulfills the research objective of detecting geothermal resources using infrared rays.

Effects of hydrogeochemistry on the microbial ecology of terrestrial hot springs.

Temperature, pH, and hydrochemistry of terrestrial hot springs play a critical role in shaping thermal microbial communities. However, the interactions of biotic and abiotic factors at this terrestrial-aquatic interface are still not well understood on a global scale, and the question of how underground events influence microbial communities remains open. To answer this, 11 new samples obtained from the El Tatio geothermal field were analyzed by 16S rRNA amplicon sequencing (V4 region), along with 191 samples from previous publications obtained from the Taupo Volcanic Zone, the Yellowstone Plateau Volcanic Field, and the Eastern Tibetan Plateau, with their temperature, pH, and major ion concentration. Microbial alpha diversity was lower in acid-sulfate waters, and no significant correlations were found with temperature. However, moderate correlations were observed between chemical parameters such as pH (mostly constrained to temperatures below 70°C), SO4 2- and abundances of members of the phyla Armatimonadota, Deinococcota, Chloroflexota, Campilobacterota, and Thermoplasmatota. pH and SO4 2- gradients were explained by phase separation of sulfur-rich hydrothermal fluids and oxidation of reduced sulfur in the steam phase, which were identified as key processes shaping these communities. Ordination and permutational analysis of variance showed that temperature, pH, and major element hydrochemistry explain only 24% of the microbial community structure. Therefore, most of the variance remained unexplained, suggesting that other environmental or biotic factors are also involved and highlighting the environmental complexity of the ecosystem and its great potential to test niche theory ecological associated questions. IMPORTANCE This is the first approach to investigate whether geothermal processes could have an influence on the ecology of thermal microbial communities on a global scale. In addition to temperature and pH, microbial communities are structured by sulfate concentrations, which depends on the tectono-magmatic settings (such as the depth of magmatic chambers) and the local settings (such as the availability of a confining layer separating NaCl waters from steam after phase separation) and the possibility of mixing with more diluted fluids. Comparison of microbial communities from different geothermal areas by homogeneous sequence processing showed that no significant geographic distance decay was detected on the microbial communities according to Bray-Curtis, Jaccard, unweighted, and weighted Unifrac similarity/dissimilarity indices. Instead, an ancient potential divergence in the same taxonomic groups is suggested between globally distant thermal zones.

Hydrochemical Characteristics and Formation Causes of Ground Karst Water Systems in Gudui Spring Catchment

As one of the famous karst springs in Shanxi Province, the Gudui spring is the only medium-low temperature hot spring, with a long history of development and a rich cultural accumulation. The karst groundwater in the Gudui spring catchment was taken as the research object. Through systematic sample collection and isotope analysis, hydrochemistry (Durov map, ion ratio, Gibbs map, and hydrogen and oxygen isotope) methods were comprehensively used to analyze groundwater hydrochemistry and groundwater system runoff characteristics. The87Sr/86Sr value of karst groundwater in the Gudui spring catchment was 0.709 to 0.717, and the Mg/(Mg+Ca) value was 0.27 to 0.74. By analyzing the Sr isotope composition and Mg/(Mg+Ca) and 1/Sr variation characteristics, it was concluded that the karst groundwater in the Gudui spring catchment was a mixture of deep hot water and shallow cold water. The karst water subsystem of Nanliang spring presented the characteristics of carbonate stratum runoff. The karst water subsystem of Fuling Mountain Gaoxian Haitou spring and the deep circulation subsystem of Houma Basin exhibited the runoff characteristics of carbonate rock and igneous rock strata. The karst water subsystem of Taiershan Jiuyuanshan Gudui spring presented the runoff characteristics of carbonate rock and ancient silicoaluminate strata. The δ18O value in karst groundwater of Guodui spring area ranged from -11.46‰ to -7.81‰, and the average value was -10.08‰. The range of the δD value was -83.7‰ to -60.8‰, and the average value was -73.6‰. This showed that karst groundwater in the spring area was the result of mixing of various types of water. Through comparative analysis of hydrogen and oxygen isotopes of 2014 and 2021 sampling points at the same location, it was concluded that the change in water samples at the Guduiquan resulted from the gradual accumulation of water supplied by Sanquan Reservoir. The change in Sanquan Reservoir was due to the influence of Yellow River diversion. The karst groundwater in the spring area were characterized by large calcium ion, magnesium ion, and sodium ion values; a small potassium ion value; a large sulfate value; and a small chloride value. The hydrochemical types of karst groundwater in Gudui spring catchment could be divided into SO4-Na, SO4-Ca, HCO3-Na, HCO3-Mg, HCO3-Ca, and Cl-Na. The hydrochemical types of karst groundwater showed evident hydrochemical composition zoning from HCO3-Ca·Mg→HCO3·SO4-Ca·Mg→SO4·HCO3-Na·Ca→SO4·Cl-Na·Ca. According to the comprehensive analysis of hydrochemical isotope and hydrogeological conditions, the karst water subsystem of Nanliang spring was primarily recharged by rainfall infiltration in the exposed limestone area and river infiltration, and its karst groundwater was recharged by runoff from south to north to the karst water subsystem of Fuling Mountain Gaoxian Haitou spring and the deep circulation subsystem of Houma Basin. The karst water subsystem of Taier Jiuyuan Mountain Gudui spring received rainfall infiltration supplement and upstream runoff supplement from the exposed limestone area. Its karst groundwater flowed from north to south and received the supply of Sanquan Reservoir from Yellow River water in the natural discharge area of Gudui spring.

Tectonic settings influence the geochemical and microbial diversity of Peru hot springs

Tectonic processes control hot spring temperature and geochemistry, yet how this in turn shapes microbial community composition is poorly understood. Here, we present geochemical and 16 S rRNA gene sequencing data from 14 hot springs from contrasting styles of subduction along a convergent margin in the Peruvian Andes. We find that tectonic influence on hot spring temperature and geochemistry shapes microbial community composition. Hot springs in the flat-slab and back-arc regions of the subduction system had similar pH but differed in geochemistry and microbiology, with significant relationships between microbial community composition, geochemistry, and geologic setting. Flat-slab hot springs were chemically heterogeneous, had modest surface temperatures (up to 45 °C), and were dominated by members of the metabolically diverse phylum Proteobacteria. Whereas, back-arc hot springs were geochemically more homogenous, exhibited high concentrations of dissolved metals and gases, had higher surface temperatures (up to 81 °C), and host thermophilic archaeal and bacterial lineages.

Structural controls of the northern Red River Fault Zone on the intensity of hydrothermal activity and distribution of hot springs in the Yunnan-Tibet geothermal belt

Deep, large faults are well-developed in the Red River Fault Zone in Yunnan in southwest China. This study uses a classification approach and macro-scale analysis of faults and hot springs with data from the literatures and field work. By examining 68 hot springs, 6 faults, and 12 Quaternary basins in this area, controls of the northern Red River Fault Zone on the intensity of hydrothermal activity (temperature and flow rates) and distribution of hot springs are summarized. The results show that topography-related hydraulic gradients can cause geothermal water to rise after circulation. The hot springs are easy to occur along the active faults (76%), especially at fault intersections (37%). The circulation depth and elevated temperature of hot springs in the study area are positively correlated. The highest temperature hot springs correspond to low flow rates, and hot springs with the highest flow rate have low temperatures. The results are of practical significance for the search for thermal groundwater and for understanding geothermal resources potential in this area and similar areas.

Geochemistry characteristics of the hungayono geothermal area for the development of clean energy in gorontalo province

Geothermal energy has great potential to provide clean energy so that the Sustainable Development Goals (SDGs) can be achieved. The purpose of this study was to identify the geochemical characteristics of the geothermal fluid in the Hungayono area. Geothermal fluid sampling is performed at two points of manifestation which have the highest temperature. The cation and anion testing of geothermal fluid using Atomic Absorption Spectrophotometer (AAS) and isotope testing using the Picarro Water Isotope Analyzer. Data analysis using Giggenbach diagrams. Hot spring temperatures are 54 - 60°C. The deposits at the point of manifestation are iron oxide with neutral fluid pH. Based on the results of the analysis of cations, anions, and isotopes, the Hungayono geothermal fluid is a type of chloride fluid that has been mixed with meteoric water. Based on the geothermometer calculation, reservoir temperature is 232-234°C. Hungayono Geothermal is a type of system with moderate to high concentration.

Understanding heat transfer along extensional faults: The case of the Ambilobe and Ambanja geothermal systems of Madagascar

Understanding the role of faults where forced convective heat transfer is the dominant mechanism giving rise to hot springs is critical in geothermal exploration in extensional environments. This study uses two-dimensional models of coupled fluid flow and heat transfer along cross-sections perpendicular to faults and the regional topography to identify favorable fault conditions for geothermal system development in northern Madagascar. Structural data collected at surface were used to define fault scenarios and simulate the ascension of hot fluids to reproduce hot spring temperatures in the Ambilobe normal fault zone area and the Ambanja graben structure. Fault dips facing topography‐driven groundwater flow was shown to be favorable, and hot spring temperatures could be reproduced when the fault permeability was > 10−14 m2. Faults located in a discharge zone near a river were the most favorable for fluid ascension, regardless of their dip. Constraining the model with a basal heat flow between 90 and 148 mWm−2 at a depth of 10 km allowed the reservoir temperature to reach 150–200 °C at depths of 2 km or shallower along favorable faults.

Geothermal Fluid Characterisics based on Geochemical Analysis of Hot Water in The Wawolesea Area, North Konawe Regency Southeast Sulawesi Province

North Konawe Regency is an area with interesting geothermal potential to be studied. The observed geothermal potential manifestation is located in the Wawolesea area through the collection and analysis of three hot spring samples. This study aims to determine the characteristics of geothermal fluids, namely the type and origin of the fluid by conducting geochemical analysis on samples of hot springs in the study area which further shows the content of elements and chemical compounds and their respective concentrations. The analysis in this research is Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) to obtain B and Li concentrations, conductivity meter to obtain Cl concentration, visible spectroscopy method for SO4 concentration and HCO3 concentration measured by acid-base titration. The results showed that the type of hot springs in the study area was included in the Chloride type with a percentage of 81.8156%-83.3976% with a pH value of 6.7-7.4 and a hot spring temperature of 50-54°C then plotted into trilinear diagram. The Cl-Li-B Ternanry diagram shows that the source of the fluid is in a reservoir that has the same rock structure and comes from the old hydrothermal system. Based on the results of the analysis of fluid characteristics obtained from the research, it can be concluded that the hot springs of the Wawolesea Region are an indicator of the presence of geothermal sources and further research is needed on the magnitude of the geothermal potential.

Geothermal potential and genetic mechanisms of the geothermal system in the mountainous area on the northern margin of north china

Geothermal resources as clean and renewable energy can be utilized for agriculture, tourism, and industry. The assessment of geothermal potential and the study of genetic mechanism of the geothermal system is an essential part of geothermal resource development. In this study, 16 steady-state temperature logs are obtained in the mountainous area on the northern margin of North China. Thermal conductivity and heat production rates are tested or collected from more than 200 rock samples of these wells and outcrops around the study area. Based on these data, for the first time, the detailed delineations of temperature distributions, genetic mechanisms of geothermal systems, and resource potential of Hot Dry Rock in the study area are achieved. The heat flow map indicates a low heat flow state with an average value of 53.1 mW/m2 in the study area, which is lower than the average value of 62.5 mW/m2 in mainland China. The distribution of hot springs in the area is mainly controlled by fault systems. Heat flow only exhibits a minor effect on the temperature of hot springs and geothermal wells. On this basis, the deep temperature distribution within 3–10 km depths of the study area is calculated using the one-dimensional steady-state heat conduction equation. With it, the reservoir depths of hot springs are estimated to be 3–5 km with temperatures ranging from 70°C to 110°C. Furthermore, a conceptual model for the geothermal system in the study area is derived. According to the results, Northeastern Chengde and northern Beijing exhibit the highest temperatures at all depths. Similar patterns are observed in the temperature distribution maps and the heat flow map, which suggest that the deep temperature distribution is mainly controlled by regional heat flow. With the depth increases, the temperature shows larger variation at each depth level, which is possibly caused by the heterogeneity of crustal composition. According to our resource assessment by volumetric method, the exploitable potential of Hot Dry Rock within the depth of 7–10 km of the study area is equivalent to about 3.1 × 1011 tons of standard coal, but the barrier is still existing for development under the current technical and economic conditions.

Geothermal energy development roadmap of Taiwan by play fairway analysis

Following the 2015 Paris Agreement dealing with the mitigation of global warming, the government and people of Taiwan have expressed their environmental awareness by accelerating the ongoing effort of substituting fossil-fuel power with green energy forms. With the deadline for promised energy policies approaching, more action is required of the geothermal option despite its high exploration cost and uncertainty issues.The Play Fairway Analysis (PFA) is an excellent low-cost decision-making tool with a quantitative approach and the capability to combine multiple factors from limited data sources and provide stakeholders a probability assessment in the early stage of the geothermal exploration. It can construct a prudent development roadmap combining geological elements alongside socioeconomic data in place.Considering the local aspects of the geological setting in metamorphic rocks and an active orogenic mountain belt uplift environment, the study adapts the PFA methodology using relevant data in geochemistry, geophysics, and geographies to depict the key geothermal factors in heat sources and fractural pathways. Existing elements available for analysis include (1) temperature of hot springs, silica geothermometry, and surface uplift rates for heat sources, and (2) active fault lines, shallow micro-earthquakes, dilatation strain rates, and elevation variation for fractural pathway. For pragmatic consideration, we choose population density and national parks to represent added human factors in this study to cover constrains such as operating cost, supply needs, regulations, and the like.Through normalizing and weighting processes from the ArcGIS platform, the resulting composite map, confirmed with previous research reports, displays the calculated values on each grid cell over the research area in an easy-to-read format. We present three suggested prospects labelled in this realistic map of potential geothermal distribution across Taiwan as candidates for the next phase of geothermal development projects as part of the long push to achieve our nation's green energy goals.

Origin of the low-medium temperature hot springs around Nanjing, China

Abstract The exploration of the origin of hot spring is the basis of its development and utilization. There are many low-medium temperature hot springs in Nanjing and its surrounding karst landform areas, such as the Tangshan, Tangquan, Lunshan, and Xiangquan hot springs. This article discusses the origin characters of the Lunshan hot spring with geological condition analysis, hydrogeochemical data, and isotope data. The results show that the hot water is SO4–Ca type in Lunshan area, and the cation content of SO4 is high, which are related to the deep hydrogeological conditions of the circulation in the limestone. Carbonate and anhydrite dissolutions occur in the groundwater circulation process, and they also dominate the water–rock interaction processes in the geothermal reservoir of Lunshan. The hot water rising channels are deeply affected by the NW and SN faults. Schematic diagrams of the conceptual model of the geothermal water circulation in Lunshan are plotted. The origin of Tangshan, Tangquan, and Xiangquan hot springs are similar to the Lunshan hot spring. In general, the geothermal water in karst landforms around Nanjing mainly runs through the carbonate rock area and is exposed near the core of the anticlinal structure of karst strata, forming SO4–Ca/SO4–Ca–Mg type hot spring with the water temperature less than 60°C. The characters of the hot springs around Nanjing are similar, which are helpful for the further research, development, and management of the geothermal water resources in this region.

What Makes a Hot-Spring Habitat “Hot” for the Hot-Spring Snake: Distributional Data and Niche Modelling for the Genus Thermophis (Serpentes, Colubridae)

Knowledge about species’ distributions is central to diverse applications in ecology, biogeography, and conservation science. Hot-spring snakes of the genus Thermophis share a distribution restricted to geothermal sites at the Tibetan Plateau (T. baileyi) and in the Hengduan Mountains (T. zhaoermii, T. shangrila). Although the suture zones of these regions are widely covered with hot springs, Thermophis populations are restricted to only a few of these habitats. Here, we use bioclimatic, topographic, and land cover data to model the potential distribution of the genus. Moreover, using logistic regression on field survey data of T. zhaoermii, we test whether hot-spring water parameters and landscape features correlate with the species’ presence or absence. Hot springs with temperatures between 45 and 100 °C and winter precipitation showed the most predictive power. At small scale, our data support the relevance of the hot-spring temperature on the species’ occurrence and indicate that also the along-valley distance from the hot-spring site to the major river might influence the distribution of Thermophis species. Our findings contribute to better understand factors shaping the current distribution of the genus and will aid in setting priorities in applied conservation biology for the hot-spring snakes.

Guideline for electricity generation from hot springs (natural energy storage systems): A techno-enviro-economic assessment

The scattered hot springs on the globe are natural thermal energy storages that are available for industrial and recreational advantages. A hot spring is a hydrothermal system that can be used for power generation purposes as well as deep-well geothermal plants. Harnessing energy from hot springs is a practical approach for a future with sustainable power supply. Therefore, there is a demand for a comprehensive study for the estimation of power generation capacity of hot springs based on their mass flow rate and temperature. A techno-enviro-economic study is conducted to estimate the power generation capacity of hot springs as a heat source of the organic Rankine cycle. The organic Rankine cycle plant is modeled and simulated for various temperatures and mass flow rates of hot springs in the present study. The impacts of the temperature and mass flow rate of hot springs on the technical and economic aspects of the power generation plants are investigated. For the hot springs with temperature and discharge mass flow rate from 60 to 90 °C and 5 to 50 kg/s, respectively, the power generation capacity alters from 9.3 kW to 303 kW and the levelized energy cost is from 0.02 $/kWh to 0.11 $/kWh. The results indicate that the hot springs with a higher temperature and discharge mass flow rate have a higher thermal efficiency and power generation capacity for the organic Rankine cycle plant while payback period, levelized energy cost, and specific investment cost shrink. The hot springs with higher temperatures and/or larger discharge mass flow rates are financially ideal candidates for initiating the power generation plants.

Genomic adaptations enabling Acidithiobacillus distribution across wide-ranging hot spring temperatures and pHs

BackgroundTerrestrial hot spring settings span a broad spectrum of physicochemistries. Physicochemical parameters, such as pH and temperature, are key factors influencing differences in microbial composition across diverse geothermal areas. Nonetheless, analysis of hot spring pools from the Taupo Volcanic Zone (TVZ), New Zealand, revealed that some members of the bacterial genus, Acidithiobacillus, are prevalent across wide ranges of hot spring pHs and temperatures. To determine the genomic attributes of Acidithiobacillus that inhabit such diverse conditions, we assembled the genomes of 19 uncultivated hot spring Acidithiobacillus strains from six geothermal areas and compared these to 37 publicly available Acidithiobacillus genomes from various habitats.ResultsAnalysis of 16S rRNA gene amplicons from 138 samples revealed that Acidithiobacillus comprised on average 11.4 ± 16.8% of hot spring prokaryotic communities, with three Acidithiobacillus amplicon sequence variants (ASVs) (TVZ_G1, TVZ_G2, TVZ_G3) accounting for > 90% of Acidithiobacillus in terms of relative abundance, and occurring in 126 out of 138 samples across wide ranges of temperature (17.5–92.9 °C) and pH (1.0–7.5). We recovered 19 environmental genomes belonging to each of these three ASVs, as well as a fourth related group (TVZ_G4). Based on genome average nucleotide identities, the four groups (TVZ_G1-TVZ_G4) constitute distinct species (ANI < 96.5%) of which three are novel Acidithiobacillus species (TVZ_G2-TVZ_G4) and one belongs to Acidithiobacillus caldus (TVZ_G1). All four TVZ Acidithiobacillus groups were found in hot springs with temperatures above the previously known limit for the genus (up to 40 °C higher), likely due to significantly higher proline and GC contents than other Acidithiobacillus species, which are known to increase thermostability. Results also indicate hot spring-associated Acidithiobacillus have undergone genome streamlining, likely due to thermal adaptation. Moreover, our data suggest that Acidithiobacillus prevalence across varied hot spring pHs is supported by distinct strategies, whereby TVZ_G2-TVZ_G4 regulate pH homeostasis mostly through Na+/H+ antiporters and proton-efflux ATPases, whereas TVZ_G1 mainly relies on amino acid decarboxylases.ConclusionsThis study provides insights into the distribution of Acidithiobacillus species across diverse hot spring physichochemistries and determines genomic features and adaptations that potentially enable Acidithiobacillus species to colonize a broad range of temperatures and pHs in geothermal environments.BoTSrZ5f8ypScVzkmXt8zFVideo

Comparison Of Isotope And Hydrochemical Characteristics Of Springs In Sembalun – Rinjani Area, East Lombok, West Nusa Tenggara, Indonesia Before And After The Earthquake Events In 2018

The current 2019 isotope and hydrochemical study of hot and cold springs in Sembalun - Rinjani area is a re-assessment of previous similar study in 2012. The aim of this study is to assess the isotope and hydrochemical characteristics of springs due to the earthquake events in 2018. After the earthquake events in 2018, the stable isotopes δ18O and δ2H composition of Sebau hot spring and most of cold springs is shifted into more depleted values which may indicate water-rock interaction or interaction with cold waters which has more depleted δ18O and δ2H values. Also, Sebau hot spring is still plotted at mixing line of meteoric and andesitic water, but still dominant meteoric water. The hydrochemical data of all cold springs and Orok river show the enrichment of Na, probably from silicates weathering or the cation exhchange. While hydrochemical composition of Sebau hot spring is significantly decreased, except SO4, probably due to dilution with cold waters before the thermal water reach the surface. The Piper diagram showed that cold springs and Orok river are Ca-Mg-HCO3 type before and after the earthquake events. While Sebau hot spring is shifted from Ca-Cl type into mixed Ca-Mg-Cl type after the earthquake events. The temperature of Sebau hot spring slightly decreased from 35.5 °C to 34.8 °C after the earthquake events, while Na/K geothermometer calculation also indicate decreasing of sub-surface temperature, i.e. from 146–165 °C to 130–150 °C.

Improving energy efficiency of the systems for obtaining water from atmospheric air

This paper outlines the prospect of obtaining water from atmospheric air by cooling it to the dew point temperature using refrigeration machines in order to partially reduce water scarcity in the arid regions of our planet. To minimize energy costs in the systems for obtaining water from atmospheric air, it is proposed to utilize solar energy with absorption refrigeration units (ARUs) acting as a source of artificial cold. The characteristic thermodynamic processes have been analyzed in a modernized ARU, capable of working at a lower thermal energy source's temperature than its analogs. The possibility has been studied to reduce the temperature of the heat source by including a solution vaporizer in the ARU scheme. The analysis involved an authentic method based on the balance of specific streams of ARU working body components and actual boundary conditions at characteristic points of the cycle. A limit was shown for the level of a minimum boiling temperature in the ARU generator (from 90 °C) when the systems for obtaining water from atmospheric air are operated under current climatic conditions. The simulation of heat-and-mass exchange processes during contact interaction between a steam-gas mixture and ammonia water solution was carried out. Based on variant calculations, it has been shown that the proposed ARU structure with an adiabatic solution vaporizer could work as part of systems to obtain water from atmospheric air at a hot spring temperature above 100 °C and constructively enough fits into the element base of standard models. It has been proposed to use two types of solar thermal energy sources to operate ARU. In a tropical climate, with vacuum solar collectors or solar energy hubs; in a temperate climate zone, with solar collectors with water as a heat carrier

Application of geothermal physics to support geotourism development in Maluku Province

This investigation aims to determine the hydrophysical gradient and the distribution of shallow surface geothermal manifestations. Geothermal manifestation data acquisition using the hydrophysical method. The manifestation of surface geothermal at the research location is only used by the local community as a place for bathing, and there is no accurate data regarding the potential of geothermal so that it can be used as a development of tourist objects (geotourism). The results showed the distribution of temperature and conductivity of surface hot springs based on hot springs around geothermal energy, consisting of two locations, namely the locations of Tulehu Village, Salahutu Subdistrict, and Nalahia Village, Nusalaut Subdistrict. The Tulehu Village location consists of two loci that are the Hatuasa locus with surface temperature values ranging from (60.1 - 80.9) °C and conductivity values ranging from (0.69 - 0.95) W/m. °C, and Talanghaha locus locations surface temperature values range from (65.5 - 67.5) °C, and conductivity values ranging from (0.68 - 0.78) W/m.°C. Whereas the location of Nalahia Village consists of the Bantang locus which has a surface temperature value of (50.1 - 61.9) °C, and the conductivity value is (0.51 - 0.71) W/m.°C. For this reason, the hydrothermal conditions of geothermal manifestations in the two research sites can be developed into geothermal hot water and maximum therapy to improve the economy of the local community and the development of the geotourism sector in Maluku Province.

Integration of Thermal Infrared and Synthetic Aperture Radar Images to Identify Geothermal Steam Spots Under Thick Vegetation Cover

Identifying physical properties of geothermal features such as surface temperature and roughness is crucial for geothermal assessment, hydrology, and environmental studies. Surface temperature and roughness-related rock properties strongly influence the thermal infrared and back-scattering intensities, respectively, of synthetic aperture radar (SAR) images. This study aimed to identify geothermal steam spots based on the surface temperature and roughness of altered surfaces, mud pools, and hot springs in tropical conditions. The thermal emissivity separation method was adopted to calculate kinetic temperature using the thermal infrared (TIR) of the advanced spaceborne thermal emission and reflection radiometer (ASTER) data as well as ground temperature data. Surface temperatures calculated by the thermal emissivity separation method were corrected using measured ground temperatures to eliminate the effects of atmospheric absorption, thermal inertia of materials, and/or diurnal temperature in the images. In addition, the linear fitting method was applied to obtain the final surface roughness model based on the calculated determination coefficient (R2) between the initial surface roughness model derived by Sentinel-1A SAR and field data. The highest R2 between surface roughness values from Sentinel-1A SAR and field data were selected to calculate spatially the surface roughness of the Wayang Windu Geothermal Field, West Java, Indonesia. The satellite imagery and field measurements showed that surface temperature and roughness features correlate with each other, and high and low thermal features correlate with high and low surface roughness values, respectively. Accordingly, we integrated the TIR and SAR data to propose the thermal resistivity index (TRI) as an indicator of the hydrothermal fluid paths to the surface. Low TRI was encountered at geothermal features and intersections of subsurface faults, which indicated weak zones that radiate heat from the subsurface to the surface.