Three-dimensional S-wave velocity structure of the upper crust in the Guangdong-Hong Kong-Macao Greater Bay Area:insights into the basins structure and genesis of hot springs

As one of the four largest bay areas with strong economic activities in the world,the Guangdong-Hong Kong-Macao Greater Bay Area(GHMGBA)is located in the zone of interaction between the South China Block(SCB)and the South China Sea(SCS).Under the influence of complex geologic evolution,basin-range structures,fault systems and hot springs are well developed here.However,the characteristics of geological structures and the genetic mechanism of these geological phenomena are still unclear.Therefore,we performed ambient noise tomography to obtain 3-D upper crust(0-7.5 km)S-wave velocity structures of the GHMGBA by using 40-day continuous waveform data from 130 seismic stations in the GHMGBA.Our results show that sedimentary basins in the GHMGBA are mainly characterized by low-velocity anomalies.S-wave velocities of sediment formation in basins are about 2.8-3.1 km/s.Rapid changes in velocity appear at the edges of the basins,which correspond to the NE-,NEE-,and NW-trending faults,indicating prominent basin-controlling effects of the faults.The Sanshui Basin(SSB),the largest in the GHMGBA,has a developmental depth of about 4 km,and there is a significant difference in velocity gradient between the east and west sides of the basin,indicating that SSB has experienced east-west asymmetric expansion.Moreover,there are prominent low-velocity anomalies at a depth of about 4.5 km beneath the hot springs at the west of the Zhujiang(Pearl)River estuary(ZRE).We infer that the low-velocity anomalies are fluid reservoirs of the hot springs,which lead to the development of the hot springs on the surface.In addition,the distribution of main cities in the GHMGBA shows a spatial correlation with low-velocity areas at shallow depths(<3 km).The population development trend in the GHMGBA in the past 20 years is also mainly concentrated in the structural province of relatively low-velocity.In combination with the GHMGBA basin structures and drainage distribution characteristics,we suggest that the basic geological environment to some extent affects the habitability of the human settlement and thus determines the distribution and development trend of the main urban context.We believe that the 3-D S-wave velocity structure of the upper crust of the GHMGBA obtained in this study,as well as the deep structural characteristics of the basins and hot springs,will provide support to urban construction planning and geological hazards research of the GHMGBA.

Influence of the Chuxiong Yao'an Earthquake on the Mineralization of Hot Springs in the Tengchong Geothermal Area,Southwestern China

The Tengchong geothermal area,an active tectonic region with frequent earthquakes,is located in Yunnan Province of southwestern China.This area contains abundant active hot springs, which often display high metal concentrations and obvious mineralization phenomena.At 19：19 on 9 July 2009,an earthquake occurred in Yao＇an,Chuxiong,Yunnan Province,which is 300 km to the northeast of the Tengchong geothermal area.We sampled water in the hot springs in the Tengchong area from 4 July to 9 July 2009 and from 10 July to 15 July 2009 to study the changes of elemental concentrations before and after the earthquake and discuss the influence of the earthquake on the mineralization of the hot springs.The concentrations of most trace elements increased slightly,but the concentration of REE（rare earth elements） decreased by 50%after the earthquake in the hot springs around a NS-trending fault.The elemental concentrations remained unchanged in Longtan and Suanshuigou,which are related to an inactive crater.The elemental concentrations in other springs controlled by superficial and small-scale faults decreased after the earthquake.The earthquake can stimulate the activity of deep faults and magma chambers,as is responsible for the increase of metal concentrations in the hot springs along the NS-trending deep fault;whereas it can decrease the porosity of permeable rocks,resulting in the decline of the flux of ore-bearing fluids and the corresponding mineralization in the hot springs related to superficial faults.

Subaerial hot springs and near-surface hydrothermal mineral systems past and present,and possible extraterrestrial analogues

The principal features,geotectonic settings and association with near-surface hydrothermal mineral systems of ancient and present subaerial hot springs,fumaroles and geysers are herein reviewed.Fumaroles and geysers usually occur in volcanic craters and are in most cases,part and parcel of hot spring environments.Subaerial hot springs are characterised by siliceous-and carbonate-rich chemical sediments,such as sinters and travertines,respectively.Sinters are commonly enriched in various metalliferous elements.Hot springs surface discharges are also characterised by pools,which exhibit bright colours due to the presence of microorganisms.Present-day examples discussed in this paper,include the fumaroles and hot springs of the White Island volcano(New Zealand),the world-renowned Yellowstone caldera(USA)and the Afar region of the East African Rift System.The Afar triangle,in the northern part of East African Rift System,provides a good example of hot springs associated with evaporative deposits.The Tuli-Sabi-Lebombo triple junction rifts were formed during the^180 Ma Karoo igneous event in southern Africa,of which the Tuli arm is the failed rift(aulacogen),as is the Afar region.The Tuli rift is effectively an unusual,if not unique,tectono-thermal setting,because it comprises Karoo-age hot springs systems and associated vein stockworks and breccias,which includes the Messina Cu deposit as well as currently active hot springs with sinter deposits probably due to post-Karoo uplift.Fumarolic pipes in ignimbrites of the Erongo Volcano-Plutonic Complex in Namibia are discussed.This is followed by an example of banded chert rocks in the Killara Formation of the Palaeoproterozoic Capricorn Orogen(Western Australia),interpreted as hot spring chemical sediments,which also show evidence of"fossil"microbial filaments.The paper ends with a brief overview of possible analogues of hot springs on planet Mars.

A culture-dependent survey of thermophilic bacteria from hot springs in Xiamen area in China

Microbes are believed to play important roles in ecosystem function in many environments.The hot springs of Xiamen Island are close to the Xiamen Sea,and may have some characteristics different from those of inland hot springs.Microbes living in the hot springs of Xiamen may have new characteristics.However,little is known about microbial communities of hot springs close to the Xiamen Sea.A culture-dependent survey of microbial population in the Xiamen hot springs was performed by using an approach combining total cellular protein profile identification and 16S rRNA gene sequencing.A total of 328 isolates of bacteria were obtained from liquid and sediment samples from the Xiamen hot springs,including neutrophilic thermophilic bacteria and moderately thermophilic acidophiles.Neutrophilic thermophilic bacteria,which grow at a temperature range of 55-90℃ including Rhodothermus marinus（Strain 1）,Thermus thermophilus（Strain 2）,Thermus thiopara（Strain 3）,Geobacillus stearothermophilus（Strain 4）,Geobacillus thermoleovorans（Strain 5）,and Pseudomonas pseudoalcaligenes（Strain 6）,were recovered by 2216E plates.Moderately thermophilic acidophiles,which can grow at temperatures above 50℃ and a pH range of 1.8-3.5 such as Alicyclobacillus acidoterrestris（Strain 8）,Sulfobacillus acidophilus（Strain 9）,and Sulfobacillus thermosulfidooxidans（Strain 10）,were isolated on selective solid medium containing sulfur and Fe2＋.Among these strains,Rhodothermus marinus,Thermus thermophilus and Geobacillus stearothermophilus are not only thermophiles,but also halophiles.One bacterium strain（Strain 6） shared 99% nucleotide sequence homology with Pseudomonas pseudoalcaligenes on the 16S rRNA gene sequence,but was quite different from Pseudomonas pseudoalcaligenes in biological characteristics,suggesting that it may represent a novel thermophilic species.Results indicated that various species of neutrophilic thermophiles and moderately thermophilic acidophiles were widely distributed in the Xiamen hot springs and that Rhodothermus marinus and Thermus thermophilus dominated the cultivable microbial community.

Microbial Mediated Mineralizationin Kamchatka Hot Springs

Materials deposited in low-temperature environments are characterized by their small particle size.The activity of microorganisms in aqueous sedimentary environments may have effective impacts on the geochemical

Microbial Mats in Tibetan Hot Springs and their Contributions to the Cesium-bearing Geyserite Ore Formation

Microbial mats, mainly dominated by filamentous algae Calothrix and Oscillatoria, are well developed in Tibetan hot springs. A great number of fossil microorganisms, which existed as algae lamination in thermal depositional cesium-bearing geyserite in this area, are identified as Calothrix and Oscillatoria through microexamination and culture experiments. These microbial mats show the ability to accumulate cesium from spring water to the extent of cesium concentration of 0.46-1.03% cell dry weight, 900 times higher than that in water, and capture large numbers of cesium-bearing opal grain. Silicon dioxide colloid in spring water replaces and fills with the organism and deposits on it to form algae laminated geyserite after dehydration and congelation. Cesium in the microbial mats and opal grain is then reserved in the geyserite. Eventually, cesium-bearing algae laminated geyserite is formed. Study on cesium distribution in geyserite also shows that cesium content in algae lamination, especially in heavily compacted algae lamination, is higher than in the opal layer. For geyserite with no algae lamination or other organism structure, which is generally formed in spring water with low silicon content, cesium accumulation and cesium-bearing opal grain assembled by the microbial mats are also indispensable. After the microbial mats accumulating cesium from spring water, silicon dioxide colloid poorly replaces and fills with the organism to form opal grain-bearing tremellose microbial mats. The shape and structure of the organisms are then destroyed, resulting in cesium-bearing geyserite with no algae lamination structure after dehydration and congelation. It is then concluded that microbial mats in the spring area contribute to the enrichment of cesium in the formation of cesium-bearing geyserite, and a biological genesis of the geyserite, besides of the physical and chemical genesis, is likely.

Biomediated Precipitation of Calcium Carbonate in a Slightly Acidic Hot Spring,Yunnan Province

A slightly acidic hot spring named ＂Female Tower＂（t=73.5°C, pH=6.64） is located in the Jifei Geothermal Field, Yunnan Province, southwestern China. The precipitates in the hot spring are composed of large amounts of calcite, aragonite and sulfur. Scanning electron microscopy（SEM） analyses reveal that the microbial mats were formed from various coccoid or rod-shaped filamentous microbes. Transmission electron microscopy（TEM） shows that the intracellular sulfur granules are commonly associated with these microbes. A culture-independent molecular phylogenetic analysis demonstrates that the majority of the bacteria in the spring are sulfur-oxidizing bacteria. In the spring water, H2S concentration is up to 60 ppm, while SO4-（2-） concentration is only about 10 ppm. We speculate that H2S might derive from sulfur-oxidizing bacteria in this hot spring water, leading to the intracellular formation of sulfur granules. Meanwhile, this reaction increased the p H in the micronscale microdomains, which fosters the precipitation of calcium carbonate in the microbial mats. The results of this study indicate that the sulfur-oxidizing bacteria might play an important role in calcium carbonate precipitation in slightly acidic hot spring environments.

A discussion of up-flow springs

Based on their genesis, springs are commonly classified as depression spring, contact spring, overflow spring and fault spring, etc. In addition, a kind of springs, i.e., up-flow spring, can be found in the field. An aquifer is overlain by poorly-permeable unconsolidated sediments or relatively impervious formations. If the hydraulic head of the aquifer is higher than the land surface, groundwater may flow up to the ground surface through the local portion of the overlying aquicludes where the permeability is relatively good, and emerges as an up-flow spring. The common characteristics of an up-flow spring are discussed and summarized in this paper, and some examples of the up-flow springs are also given. Up-flow springs can flow up through local permeable zones in the overlying aquicludes rather than permeable faults. Although they cannot be found as frequently as depression springs, contact springs, overflow springs and fault springs etc., yet up-flow springs may occur in the form of normal-temperature springs, hot springs and salt springs.

Characterization of a Novel MDH1 Bacterium from a Virgin Hot Spring Applicable for Gold Nanoparticle (GNPs) Synthesis

Background: Use of novel microorganisms for beneficial purposes is still remaining a challenging job. This study was designed to isolate, characterize and use of a novel hot spring bacterial strain from a virgin hot spring of Metaldanga, Birbhum, West Bengal, India. Methods: A pure bacterial strain (MDH1) was identified by growing the enrichment culture isolated from Metaldanga hot spring through serial dilution process in a semi-synthetic medium at pH 8.0 and 42&deg;C temperature. The novelty of the strain was characterized by 16S-rRNA gene sequence analysis. The bacterium acted as template to synthesize spherical gold nanoparticles (GNPs). GNPs were characterized by using UV-Vis spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS) and Fourier transform infra-red spectroscopy (FTIR). Results: The phylogenetic analysis suggested that MDH1 strain (GenBank accession number: KT600031) was affiliated to the family “Pseudomonadaceae” with 99% homologous to Pseudomonas putida H8234. The coccoid shaped bacterium was gram-negative and facultative-anaerobic which acted as a template to synthesize spherical GNPs with an average size of 12 ± 3 nm when examined under transmission electron microscopy (TEM). FT-IR studies revealed the presence of bioactive functional groups which acted as capping and stabilizing agents of the GNPs. XRD pattern confirmed the amorphous nature of GNPs. The Zeta potential (ζ) concluded the adequate stability of GNPs in an aqueous environment. Conclusions: The present investigation explores the microbial diversity of a virgin hot spring of Metaldanga for its beneficial applications in industry, particularly in the synthesis of the gold nanoparticles.

Ultrastructural Evidence for a Novel Accumulation of Ca in a Microbial Mat from a Slight Acidic Hot Spring

Microbial mats are ecosystems that can control or induce the precipitation of calcium（Ca） carbonate on Earth through geological time.In the present study,we report on a novel accumulation of Ca,together with iron（Fe）,in a microbial mat collected from a slight acidic hot spring（pH=5.9） in south China.Combining an array of approaches,including environmental scanning electron microscopy,X-ray microanalysis,transmission electron microscopy,and selected area electron diffraction,we provide ultrastructral evidence for amorphous acicular aggregates containing Ca and Fe associated with cyanobacteria precipitating in the microbial mats.Cyanobacterial photosynthesis and exopolymeric organic matrixes are considered to be responsible for the precipitation of Ca.These amorphous acicular aggregates might imply the early stage of calcification occurring in microbial mats.Ca and Fe coprecipitation indicates another potential important way of inorganic element precipitation in hot spring microbial mats.Our results provide insight into the possible mechanism of cyanobacterial calcification and microfossil preservation in slight acidic hot spring environments.

Mathematical Model of the Geothermal Water Resources in the South Hot Spring System in Chongqing

The geothermal waters of south hot spring, small hot spring and Qiaokouba in Chongqing, are all part of the south hot spring geothermal water system. Exploitation has caused a decline in the water levels of the south and small hot springs, which have not flowed naturally for 15 years. Now, bores pump geothermal water to the springs. If the water level drops below the elevation of the rivers, river-water will replenish the geothermal water, destroying this resource. It is therefore an urgent task to model the geothermal water system, to enable sustainable development and continued use of the geothermal water in Qiaokouba. A numerical simulation of the geothermal water system was adopted and a quantitative study on the planning scheme was carried out. A mathematical model was set up to simulate the whole geothermal water system, based on data from the research sites. The model determined the maximum sustainable water yield in Qiaokouba and the two hot springs, and the south hot spring and small hot spring sustainable yields are 1 100 m^3/d and 700 m^3/d from 2006 to 2010, 1 300 m^3/d and 1 000 m^3/d from 2011 to 2015, and 1 500 m^3/d and 1 200 m^3/d from 2016 to 2036. The maximum exploitable yield is 3 300 m^3/d from 2006 to 2036 in Qiaokouba. The model supplies a basis to adequately exploit and effectively protect the geothermal water resources, and to continue to develop the geothermal water as a tourist attraction in Chongqing.

Evaluation of Pencil Lead Based Electrodes for Electrocardiogram Monitoring in Hot Spring

Electrocardiogram(ECG)electrodes are conductive pads applied to the skin to measure cardiac activity.Ag/AgCl electrodes are the commercial product which widely used to obtain ECGs.When monitoring the ECG in a hot spring,Ag/AgCl electrodes must be waterproofed;however,this is time-consuming,and the adhesive may tear the skin on removal.For solving the problem,we developed the carbon pencil lead(CPL)electrodes for use in hot springs.Both CPL and Ag/AgCl electrodes were connected to ECG100C’s cables.The Performance was evaluated in three conditions as following:hot spring water with and without bubble,and in cold water.In each environment,the procedure was followed by three different protocols that are recording from the dry condition,hot spring water immersion with and without movement,post hot spring water condition.Under dry and wet conditions,both electrodes can obtain the waveform of the ECG signal in which all PQRST waves were identifiable.Nevertheless,the signal quality of both types of electrodes was different in water immersion with and without movement.The overall morphology obtained by Ag/AgCl electrodes was unstable higher than that of CPL electrodes in immersion without movement condition.The CPL electrodes provided better ECG waveform quality compared to Ag/AgCl electrodes in which the ECG signal had high waveforms distortion in water immersion with movement condition.

Fault－weakening effect of reservoir temperature of hot spring and its influence on seismic activities

In this paper, the reservoir temperatures of 14 hot spring samples collected from the northern segment of theRed River Fault are calculated by using the mixing-model of SiO2-geothermometer. Based on the features ofreservoir temperatures and densities of hot springs, the northern segment of the Red River Fault is furtherdivided into 4 sub-segments. The influence of weakening effect of water on seismic activities is discussed fromthe view point of fault-weakening effect of water. It is suggested that the difference in seismic activity between various sub-segments is principally caused by the difference in intensity of the fault-weakening effect ofwater of these sub-segments. The Eryuan sub-segment where the reservoir temperatures are high and the hotsprings are dense corresponds to a slipped region, however, the Jianchuan and Midu sub-segments where thereservoir temperatures are lower and the hot springs are fewer as well as the Dan sub-segment where the hotspring are very few all correspond to locked regions. It is suggested that Dan sub-segment is the riskiest region for strong earthquake preparation, while the possibility for strong earthquake preparation is very little inthe Eryuan sub-segment.

Phylogenetic Characterization of BKH3 Bacterium Isolated from a Hot Spring Consortium of Bakreshwar (India) and Its Application

Background: The silica leaching attribute of some of the mystifying bacteria present in the cluster of hot springs (temperatures range 35°C - 80°C) at Bakreshwar (West Bengal, India, 23°52'48"N;87°22'40") has provided some significant advancements in construction technology when incorporated to the concrete/mortar specimens. The present investigation was designed to isolate other novel bacterial strains from 65°C hot spring that could have similar or better performance in construction technology. Methods: Soil sample collected from the 65°C hot spring was inoculated to the culture vials (incubated at 65°C) containing a specific synthetic growth medium (pH 8.0) to grow the bacterial population anaerobically by degassing the medium with CO2 gas. Subsequent serial dilution techniques were employed to isolate pure culture of a specific bacterial strain. 16S rRNA gene sequence and phylogenetic analysis was carried out to identify the novelty of the isolated bacterial strain. The isolated bacteria were incorporated to the cement sand mixture at various cell concentrations to evaluate the efficacy of the strain in construction technology. Results: The work revealed the presence of a novel bacterial strain (BKH3;GenBank Accession No.: KP 890928) within the same hot spring consortium whose 16S rRNA gene sequence data showed 96% identity with Citrobacter freundii bacterial species. The newly isolated bacteria when incorporated at different cell concentration to the cement/cement-sand mixture were found to possess the similar compressive strength increment property, the cracks repairing ability and the water ingression resistivity. It also reduced the permeability of sulphate ions to the cementitious matrix reflecting the increment of durability of the incorporated material. Conclusions: The enhancement of compressive strength and durability of the as prepared bio-concrete material by using the isolated bacterial strain (BKH3) was due to the silica leaching activity of the bioremediase like protein secreted by the bacterium. This may open up another vista of utilization of hot spring bacterium for beneficial purposes in construction technology.

Removal of Lead Contamination through the Formation of Lead-Nanoplates by a Hot Spring Microbial Protein

Lead contamination still remains as serious threat to public health and environment because of its non-biodegradability and toxicity. A clean technique has been developed for removal of lead contamination through the formation of lead-oxide nanoplates using a bacterial protein (Molecular weight ~30 kDa) as biological template. The isolated hot-spring bacterial (the bacterium was named as MDH1) protein when adding to the solution of lead compound (e.g., lead nitrate), nanoplates of lead-oxide are formed as viewed by electron microscope. The as prepared lead-oxide-nanoplates are characterized by Inductively Coupled Plasma analysis, Energy Dispersive X-ray Spectroscopy and X-ray diffraction analyses. The lead-oxide-nanoplates and the filtered supernatant of the reactive solution both were separately used to observe the inhibition of growth of E. coli bacteria on culture plate. Lead-oxide-nanoplates produced clear zone of inhibition on the bacterial growth plate, whereas the filtered supernatant exhibited no such zone on the growth of E. coli bacteria revealing the fact that lead contamination was removed from the filtered supernatant. The prepared lead oxide nanoplates also possess dye degradation activity which is the added advantage of the process. The MDH1 bacterial protein acts as biological template which successfully removes lead contamination from lead-solution. The process is a clean and cost-effective one which can be used not only for removal of lead contamination but also for removal of different dyes from environment due to having dye-degradation attribute of the lead-oxide nanoplates.

Analysis on the Industrial Development Plan of the Tribal Hot Spring Demonstration Area in Taiwan’s Indigenous Areas

Under the impact of modern life, the traditional culture of Taiwan’s indigenous tribes is not only affected, because the traditional life is not easy and employment is difficult, which also causes the outflow of tribal population. Therefore, after the establishment of the Taiwan Council of indigenous people (TCIP), tourism development has been listed as an important policy, and it wants to use tourism development to improve the lives of indigenous people and enhance the ability of tribal economic development. The purpose of this study is to analyze the advantages and disadvantages of TCIP in developing tribal hot spring demonstration areas in indigenous areas. This study adopts the method of case study to investigate by means of document analysis, field interview and observation. The results of SWOT analysis show that: 1) Advantages: the indigenous tribes are rich in natural resources and have unique cultural characteristics. 2) Weakness: when indigenous people invest in hot spring industry, they will face difficulties in obtaining development funds, lack of land use and hot spring management talents. 3) Opportunities: Because of the prevailing leisure culture in Taiwan, coupled with the relevant laws and policies and plans of the indigenous people, it is guaranteed that the indigenous people can participate in the development plan of the hot spring demonstration area. 4) Threats: The development of the existing hot springs in the indigenous villages and towns is mostly invested by the Han people, so it is difficult for the indigenous people to compete with them. Moreover, they lack the management ability and guidance to enter the competitive market of hot spring development.

BATHING IN MANGPU HOT SPRING IN LHATSE

Lhastse County in Shigatse Prefecture is well-known by multiple names such as the "North Entrance of theQ omolangma,""Food Grains Storage,""Hometown of Tibetan Knives,""Hometown of Dorxic (a kind of Tibetan music)" and also "the Way to Pilgrim". "Lhastse", in Tibetan, refers to the "Summit of Manitou". Int he secular world, it is called "Laxog" meaning "the holy place where the sunlight first touches" Naturally, some scholars prefer to dub "Lhastse" as"a place suffering from drought".

Geothermal anomalies in the Xianshuihe area: Implications for tunnel construction along the Sichuan-Tibet Railway, China

This study presents a comprehensively analysis of geothermal characteristics in the Xianshuihe geothermal area along the Sichuan-Tibet Railway,using temperature logging,temperature monitoring and thermal conductivity measurement,and regional geothermal geological survey data.The research focuses on the geothermal background,geothermal field,and their potential impact on the surrounding tunnels.The investigation reveals that the average heat flow value in the study area is approximately 73.0 mW/m^(2),significantly higher than the average terrestrial heat flow in China's Mainland(62.5 mW/m^(2)).This high terrestrial heat flow signifies a distinct thermal background in the area.In addition,geothermal anomalies in the area are found to be closely associated with the distribution of hot springs along NW faults,indicating a strong control by the Xianshuihe fault zone.The study concludes that the region's favorable conditions for geothermal resources are attributed to the combination of high terrestrial heatflow background and water-conducting faults.However,these conditions also pose a potential threat of heat damage to the tunnels along the Sichuan-Tibet Railway.To evaluate the risk,the research takes into account the terrestrial heat flow,thermal conductivity of the tunnel surrounding rocks,characteristics of the regional constant temperature layer,as well as the distribution of hot springs and faults.The analysis specifically focuses on the thermal damage risk of Kangding 1# tunnel and 2# tunnel passing through the study area.Based on the findings,it is determined that Kangding 1# tunnel and 2# tunnel have relatively low risk of heat damage,as they have avoided most of the high temperature anomaly areas.However,several sections of the tunnels do traverse zones with low to medium temperatures,where surface rock temperatures can reach up to 45℃.Therefore,these regions should not be neglected during the construction and operation of the tunnel project,and mitigation measures may be necessary to address the potential heat-related challenges in the area.

Improved Preproduction Conceptual-Numerical Model of the Roosevelt Geothermal Field using Geological, Geochemical and Structural Information

The Roosevelt Hot Springs Known Geothermal Resource Area(KGRA) is a Basin and Range-type geothermal resource, which is located in southwestern Utah. The integrated multicomponent geothermometry(IMG) approach is used to estimate the reservoir temperature at the Roosevelt Hot Springs KGRA. Geothermometric modeling results indicate the deep reservoir temperature is approximately 284.6°C. A conceptual model of the Roosevelt Hot Spring KGRA is provided through integrating the various pieces of exploration information, including the geological data, geothermometric results, temperature well log and field evidence. A two-dimensional cross-sectional model was thus built to quantitatively investigate the coupled thermal-hydraulic processes in the Roosevelt geothermal field. By matching the preproduction temperature log data of deep wells, parameters controlling flow and heat transport are identified. The method and model presented here may be useful for other geothermal fields with similar conditions.

Geothermal,Oceanic,Wildfire,Meteorological and Anthropogenic Impacts on PM_(2.5) Concentrations in the Fairbanks Metropolitan Area

The impacts of low and high-frequency variability from teleconnections between large scale atmospheric processes and local weather as well as emissions changes on concentrations of particulate matter of 2.5 μm or less in diameter ([PM2.5]) were examined for the Fairbanks Metropolitan Area (FMA). October to March and May to August mean [PM2.5] were 1.8 and 3.1 μg&#183;m&#45;3 higher for positive than negative annual mean Pacific Decadal Oscillation. Annual mean [PM2.5] were 3.8 μg&#183;m&#45;3 lower for positive than negative Southern Oscillation Index. On 1999-2018 average, [PM2.5] decreased 2.9 μg&#183;m&#45;3&#183;decade&#45;1. On average over October to March, decadal and inter-annual variability caused higher or similar differences in mean observed [PM2.5] and its species than emission-control measures. The 2006 implementation of Tier 2 for new vehicles decreased observed sulfate concentrations the strongest (~4.95 μg&#183;m&#45;3&#183;decade&#45;1) of all occurred emissions changes. On average, observed [PM2.5] showed elevated values at all sites when wind blew from directions of hot springs. The same was found for the sulfate, ammonium and non-metal components of PM2.5. Observations showed that these geothermal waters contain sulfate, ammonia, boric acid and non-metals. Hot springs of such composition are known to emit hydrogen sulfide and ammonia that can serve as precursors for ammonium and sulfate aerosols.