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1.
运用热流、地温梯度及温泉等资料,划分了黄河上游地区的地热异常区,讨论了地热与构造及地震的关系。认为断裂构造及深部热源是地热异常的主要成因;在空间上,强震分布与热异常区的分布呈相关关系。 相似文献
2.
川西高温水热活动区是地热学研究的典型地区之一,该区温泉、热泉点分布广泛,这些温泉大多沿北西-南东向的金沙江断裂、德格-乡城断裂、甘孜-理塘断裂、鲜水河三条主断裂呈条带状分布.对此高温水热活动区开展地热学分析,是研究青藏高原"东构造结"深部地球动力学过程、开发利用川西高原地热资源的重要基础,具有重要的科学研究意义和实际应用价值.本文针对实测氦同位素所发现的壳幔热结构比,依据重力、航空磁法、地震资料,采用反演莫霍面、居里面深度等方法,对川西高温水热活动区的深部热结构进行了分析.同时对中高温热泉密集出露的巴塘、理塘以及康定水热活动区的典型壳幔热流构与深部背景场进行了对比研究.结果表明,地表氦同位素热流估算的深部热流结构与地球物理异常结果保持较好的对应关系.川西地区热流结构中地壳、地幔的热贡献比较接近：巴塘地区平均Qc/Q=51.38%、理塘地区平均Qc/Q=54.39%、康定地区平均Qc/Q=42.42%.川西地区表现出了"温壳温幔"型的深部热结构,但温地壳背景下形成较高地表热流的原因有待进一步研究. 相似文献
3.
4.
丽江7.0级地震地表破裂与形变特征 总被引：11，自引：3，他引：11
丽江７．０级地震序列发生在该地区属次级构造的断裂上，而且这次地震的烈度分布，地表破坏分布和强余震分布都表现了异常不均匀性。根据大震震害损失评估调查和大震现场地面破坏调查取得的资料，对上述异常现象的原因进行了初步分析，认为主震发震构造为玉龙山山前近南北向断裂，但其破裂过程可能存在“跳跃”和偏转。 相似文献
5.
山西断陷带地热分布的某些特征 总被引：1，自引：0，他引：1
利用山西断陷带的大地热流、地温梯度和温泉分布的资料，研究了地热分布与重力场、地壳深部构造和地震分布的关系。认为，区域性重力负异常多反映的是沉积盆地或凹陷；而在温泉附近，由于地壳深部高密度的熔融物质沿断裂上涌而形成重力正异常；在同一深度上，地壳和岩石圈薄的断陷盆地内部，其热流和温度都为高值；指出山西断陷带内的构造活动性、壳幔突变带、重磁力等值线密集带、大地热流和地温梯度高值区以及温泉密集分布带与地震活动之间都有着内在的联系。 相似文献
6.
《地球物理学报》2020,(9)
滇西北宾川盆地是发育于红河断裂和程海断裂交汇处的晚新生代张扭断陷盆地,该区活动断裂发育且历史地震比较活跃.对宾川盆地及邻区进行高精度浅层和上地壳精细结构研究,有助于深入认识该区主要发震构造的深浅部特征.基于2017年在宾川盆地及其附近开展的为期2个月的密集台阵观测数据,我们对该区96个小震共拾取了117221条初至P波和5475条初至S波震相,并利用simul2000开展了地震重定位和体波层析成像研究.结果表明:(1)小震活动主要集中在宾川盆地东缘断裂的弧形转折部位,并在洱海南侧呈现沿北东向断裂的条带状分布现象,反映了区域上近南北向至北东向断裂是主要控震构造,其次是北西向断裂带.(2)0 km的速度分布与区域地形有很好的对应关系.山地呈现高速异常,宾川盆地呈现低速异常.从3 km至9 km,高低速分界与断层有很好的对应,并且越往深部,近南北向至北北东向的宾川盆地东缘断裂在上地壳构造的控制作用越明显.(3)上地壳层析成像结果同时揭示了宾川盆地东缘断裂的三维形态变化在空间上呈现出南北部倾角大、中部倾角缓的变化特征,可能与区域地块的旋转变形过程有关.(4)综合高精度浅层速度结构和地震重定位结果可知,区域上的近南北向至北北东向断裂正逐步取代北西向构造,成为主要的区域分界断裂和控震构造.新的研究结果为深入理解该区的主要控震构造及其深部结构特征提供了重要依据. 相似文献
7.
华南地区温泉地震和活动性断裂关系的研究 总被引：1，自引：0，他引：1
我们在编制“湖南省主要活动性断裂构造图”(1/100万)的过程中看到了一个很有趣的现象,即:①温泉大体上沿活动性断裂呈串珠状分布,并基本上分布于断裂的上盘,或分布于主干断裂派生的羽状断裂上;②出露于坚硬基岩地区的温泉,温度往往偏 相似文献
8.
小江断裂带属现今仍在活动的断裂,同时也是一条破坏性地震多发带。为探究特定地区的地球化学场与地震的耦合关系,寻找特定的前兆观测组分,笔者选取并计算了小江断裂带及邻近地区的95处温泉的热储温度。利用温泉的水化学数据(K+、Na+、Ca2+、Mg2+、SO2-4、Cl-、HCO-3),结合该区域的构造特征及地震活动规律,对温泉的水化学、水温、热储温度、稳定同位素(δ13C,3He/4He)等地球化学特征进行了研究。结果表明温泉中主要离子含量、TDS含量、水温及热储温度的高值区域在空间上主要沿小江断裂带展布,且呈北高南低的分布特征。水温和热储温度高值区内中强地震(M≥4.7)分布少;相反,低值区内中强震活动频繁,且强度相对较大。碳、氦同位素特征显示,CO2气体的碳同位素(δ13C)组成具有明显的生物成因特征;幔源氦(百分含量)同素所占比例相对较低,表明小江断裂带中南段壳幔连通程度低,脱气作用几乎都发生在地壳范围。 相似文献
9.
滇西北宾川盆地是发育于红河断裂和程海断裂交汇处的晚新生代张扭断陷盆地,该区活动断裂发育且历史地震比较活跃.对宾川盆地及邻区进行高精度浅层和上地壳精细结构研究,有助于深入认识该区主要发震构造的深浅部特征.基于2017年在宾川盆地及其附近开展的为期2个月的密集台阵观测数据,我们对该区96个小震共拾取了117221条初至P波和5475条初至S波震相,并利用simul2000开展了地震重定位和体波层析成像研究.结果表明：（1）小震活动主要集中在宾川盆地东缘断裂的弧形转折部位,并在洱海南侧呈现沿北东向断裂的条带状分布现象,反映了区域上近南北向至北东向断裂是主要控震构造,其次是北西向断裂带.（2）0 km的速度分布与区域地形有很好的对应关系.山地呈现高速异常,宾川盆地呈现低速异常.从3 km至9 km,高低速分界与断层有很好的对应,并且越往深部,近南北向至北北东向的宾川盆地东缘断裂在上地壳构造的控制作用越明显.（3）上地壳层析成像结果同时揭示了宾川盆地东缘断裂的三维形态变化在空间上呈现出南北部倾角大、中部倾角缓的变化特征,可能与区域地块的旋转变形过程有关.（4）综合高精度浅层速度结构和地震重定位结果可知,区域上的近南北向至北北东向断裂正逐步取代北西向构造,成为主要的区域分界断裂和控震构造.新的研究结果为深入理解该区的主要控震构造及其深部结构特征提供了重要依据. 相似文献
10.
利用SiO2地热温标的混合模式, 计算了红河断裂带北段14个温泉的热储温度, 并根据温泉热储温度和温泉密度的特征, 把红河断裂带北段进一步划分为4个亚段。从水对断裂弱化作用的角度, 讨论了水的弱化作用对地震活动的影响, 认为各亚段水对断裂弱化作用的强度的不同, 是引起各亚段地震活动差异的重要原因。热储温高、温泉密集的洱源亚段相当于滑移区;而热储温度较低。温泉较少的剑川亚段和弥渡亚段及温泉稀少的大理亚段则相当于闭锁区,认为大理亚段是孕育强震的最危险地区, 洱源亚段孕育强震的可能性很小。 相似文献
11.
A geochemical study of thermal and cold springs, stream waters and gas emissions has been carried out in the Mt. Amiata geothermal region.The cold springs and stream waters do not seem to have received significant contribution from hot deep fluids. On the contrary, the thermal springs present complex and not clearly quantifiable interactions with the hot fluids of the main geothermal reservoir.The liquid-dominated systems in the Mt. Amiata area, like most of the high-enthalpy geothermal fields in the world, are characterized by saline, NaCl fluids. The nature of the reservoir rock (carbonatic and anhydritic), and its widespread occurrence in central Italy, favor a regional circulation of “Ca-sulfate” thermal waters, which discharge from its outcrop areas. Waters of this kind, which have been considered recharge waters of the known geothermal fields, dilute, disperse and react with the deep geothermal fluids in the Mt. Amiata area, preventing the use of the main chemical geothermometers for prospecting purposes. The temperatures obtained from the chemical geothermometers vary widely and are generally cooler than temperatures measured in producing wells.Other thermal anomalies in central Italy, apart from those already known, might be masked by the above-mentioned circulation. A better knowledge of deep-fluid chemistry could contribute to the calibration of specific geothermometers for waters from reservoirs in carbonatic rocks. 相似文献
12.
Behrooz Oskooi Mahmoud Mirzaei Behnam Mohammadi Mohammad Mohammadzadeh-Moghaddam Feridon Ghadimi 《Studia Geophysica et Geodaetica》2016,60(1):141-161
Magnetotelluric (MT) and ground magnetic surveys were conducted on the Mahallat geothermal field situated in Markazi province, central Iran, as a primary part of the explorations and developments of a geothermal energy investigation program in the region. Mahallat region has the greatest geothermal fields in Iran. MT survey was performed in November 2011 on an 8 km profile crossing the hot springs with a total of 17 stations. The 2D inversion of the determinant MT data was performed using a 2D inversion routine based on the Occam approach. The 2D resistivity model obtained from the determinant data shows a low resistivity zone at 800-2000 m depth and a higher resistivity zone above the low resistivity zone, interpreted as geothermal reservoir and cap rock, respectively. It also revealed two major concealed faults which are acting as preferential paths for the circulation of hydrothermal fluids. To obtain more geophysical evidence, a ground magnetic survey with 5000 stations was also performed over an area of 200 km2 around the MT profile. Magnetic measurements show a main positive anomaly of about +1000 nT over the study area, which could be interpreted as an intrusive body with the high magnetic susceptibility (i.e. mafic and ultramafic rocks) into the sedimentary host rocks. We interpret the body as the heat source of the geothermal system. Structural index and depth estimation of the anomaly indicate that the intrusive body is similar to a cylinder extending from about one kilometer depth down to greater depths. The results of MT and magnetic investigations indicate a geothermal reservoir which proves the preliminary geological observations to a great extent. 相似文献
13.
Grant Heiken Napoleon Ramos Wendell Duffield John Musgrave Kenneth Wohletz Sue Priest James Aldrich Wilmer Flores Alexander Ritchie Fraser Goff Dean Eppler Carlos Escobar 《Journal of Volcanology and Geothermal Research》1991,45(1-2)
The Platanares geothermal area, Departamento de Copán, Honduras, is located within a graben that is complexly faulted. The graben is bounded on the north by a highland composed of Paleozoic (?) metamorphic rocks in contact with Cretaceous - Tertiary redbeds of unknown thickness. These are unconformably overlain by Tertiary andesitic lavas, rhyolitic ignimbrites, and associated sedimentary rocks. The volcanic rocks are mostly older than 14 Ma, and thus are too old to represent the surface expression of an active crustal magma body. Thermal fluids that discharge in the area are heated during deep circulation of meteoric water along faults in a region of somewhat elevated heat flow. Geothermometry based upon the chemical composition of thermal fluids from hot springs and from geothermal gradient coreholes suggests that the reservoir equilibrated at temperatures as high as 225 to 240°C, within the Cretaceous redbed sequence. Three continuously cored geothermal gradient holes have been drilled; fluids of about 165°C have been produced from two drilled along a NW-trending fault zone, from depths of 250 to 680 m. A conductive thermal gradient of 139°C/km, at a depth of 400 m, was determined from the third well, drilled 0.6 km west of that fault zone. These data indicate that the Platanares geothermal area holds considerable promise for electrical generation by moderate- to hightemperature geothermal fluids. 相似文献
14.
During two expeditions in the Danakil depression (Ethiopia), water samples were collected from: (a) hot springs in Dallol, Salt Plain, in the north of the depression; (b) cold and hot springs around Lake Giulietti; and c) Lake Giulietti.The isotopic results indicate: the water from Dallol hot springs is enriched in18O by isotopic exchange with the rocks as has been observed in many other geothermal areas of the world; b) the isotopic composition of the Lake Giulietti water changes with depth, probably as a consequence of a seasonal stratification; c) the springs in the Lake Giulietti region contain waters which result from the mixing of local meteoric water with a brine, or with lake waters. 相似文献
15.
George Papantonopoulos Konstantinos Modis 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,20(1-2):23-32
This work develops a model of the geothermal field in the Nea Kessani region (Greece) by means of the Bayesian maximum entropy
(BME) method, which describes the temperature variations across space in the underground geological formations. The geothermal
field is formed by a thermal reservoir consisting of arcosic sandstones. The temperature distribution vs depth was first investigated
by the Greek Institute of Geology and Mineral Exploration (IGME) using measurements in a set of vertical drill holes. These
measurements showed that hot fluids rising from the deep enter the reservoir in a restricted area of the field and flow towards
local thermal springs. The field modelling, which was based on the powerful BME concept, involves the solution of a stochastic
partial differential equation that assimilates important site-specific information. The stochastic three-dimensional steady-state
Laplace equation was considered as general knowledge and the drilling exploration data were used to construct the specificatory
knowledge base in the BME terminology. The produced map is more informative and, in general, it gives higher temperature estimates
compared to previous studies of the same region. This is also in agreement with the quartz geothermometry analysis carried
out by IGME. 相似文献
16.
In this study the geodynamical scenario along with concepts of mantle plume and mobile belts is utilized to show that most of the existing and potential high thermal regions fall along the (mobile arms affected by the outburst and) traces of mantle plumes. Effects of channeling and partitioning of thermomagmatic flux (TMF) due to these mantle plumes along the mobile belts, particularly near the triple junctions, can be seen in the form of high heat flow and presence of hot springs. Triple junctions manifest over the Indian lithosphere are: Kutch-Cambay, Narmada Son-Godavari, Tapi-Mahanadi, Tapi-Damodar, Pondicherry region, Gulf of Mannar and SW corner of the subcontinent (off-shore), etc. Apart from mobile belts, the deltaic regions of Krishna, Godavari, Ganga, Cauvery, Narmada-Tapi and Indus, etc., are also posses higher level of thermal anomalies as these regions seem to have been substantially influenced by outbursts and traces of Reunion, Kerguelen, Marion and Crozet hotspots. This is reflected from the correlation between plume affected mobile belts and high heat flow regions, large number of hot springs, anomalous electrical conductivity and also deformation or seismicity. Such correlation can be seen along Cambay, west coast trend, Narmada-Son lineament zone, Godavari-Damodar grabens and Bengal basin. Himalayan belt being ongoing collision zone, thermal anomalies are identified in the form of hot springs along the Himalayan arc. At some locations, which might be junction of tectonic trends, there exist significantly large thermal outputs. Puga in Himalayan region is one such example, as seen from high heat flow (max. 468 mW m− 2) and geothermal gradient (234 °C/km max.). Similarly, Tatapani in Narmada Son Lineament (NSL) region is another such example. The present study discusses the correlation between thermal reservoirs identified by magnetotelluric (MT) study results and plume activity and suggests the need for systematic and detailed MT investigations along plume activated mobile strips in other regions to search for geodynamical history and geothermal resources. 相似文献
17.
Serkan Üner Gülçin Özürlan Ağaçgözgü Doğa Düşünür Doğan 《Geophysical Prospecting》2019,67(8):2176-2195
Western Anatolia hosts many low-to-moderate and high-temperature geothermal sources in which active faults play a dominant role to control the recharge and the discharge of geothermal fluid. In this study, we used the two-dimensional geoelectric structure of Kütahya Hisarcık geothermal field, and created a conceptual hydrogeophysical model that includes faults, real topographical variations and geological units. The temperature distribution and fluid flow pattern are also investigated. The depth extension of Hisarcık Fault, electrical basement and low resistivity anomalies related to the presence of geothermal fluid are determined by using resistivity studies in the area. Numerical simulations suggest that Hisarcık fault functioning as a fluid conduit primarily enables hot fluid to be transported from depth to the surface. It is shown that the locations of predicted outflow vents coincide with those of hot springs in the area. 相似文献
18.
Ground water can facilitate earthquake development and respond physically and chemically to tectonism. Thus, an understanding of ground water circulation in seismically active regions is important for earthquake prediction. To investigate the roles of ground water in the development and prediction of earthquakes, geological and hydrogeological monitoring was conducted in a seismogenic area in the Yanhuai Basin, China. This study used isotopic and hydrogeochemical methods to characterize ground water samples from six hot springs and two cold springs. The hydrochemical data and associated geological and geophysical data were used to identify possible relations between ground water circulation and seismically active structural features. The data for delta18O, deltaD, tritium, and 14C indicate ground water from hot springs is of meteoric origin with subsurface residence times of 50 to 30,320 years. The reservoir temperature and circulation depths of the hot ground water are 57 degrees C to 160 degrees C and 1600 to 5000 m, respectively, as estimated by quartz and chalcedony geothermometers and the geothermal gradient. Various possible origins of noble gases dissolved in the ground water also were evaluated, indicating mantle and deep crust sources consistent with tectonically active segments. A hard intercalated stratum, where small to moderate earthquakes frequently originate, is present between a deep (10 to 20 km), high-electrical conductivity layer and the zone of active ground water circulation. The ground water anomalies are closely related to the structural peculiarity of each monitoring point. These results could have implications for ground water and seismic studies in other seismogenic areas. 相似文献
19.
A geothermal field producing dry steam or high temperature water is a trap for convection currents generated in an aquifer of high permeability and of sufficient thickness by a deep heat source. A basic implication of this concept is, that a geothermal field requires a cap-rock of more or less impermeable rocks above the producing aquifer. In Larderello, Monte Amiata, and Salton Sea geothermal fields, a clearly reconnaissable tight formation overlies the producing zone and limits the upward movements of the convection currents. In other fields,i.e. The Geysers (California), Wairakei and Waiotapu (New Zealand) we do not know a geologically well defined cap-rock formation, presenting a large difference in permeability in comparison with the reservoir formation. The hot water circulating in a hydrothermal system without a cap-rock can produce deposits and rock alteration in proper places along the flow paths. The tracture and pore filling and any other permeability reducing factors increase resistance to the water circulation: those processes can originate an effective cap-rock. By such processes a hydrothermal system can become a self-sealed geothermal field. The silica deposition is probably the main self-sealing process. In fact, 1) silica is very common. 2) it is available with almost no limitation, 3) its deposition is strictly related to temperature changes, and 4) it is likely to produce very effective patterns of deposition. Where an unlimited CO2 supply is available at depth, the calcium carbonate deposition appears to be a noticeable sealing process, which is controlled by pressure, at relatively shallow depth. In other cases CaCO3 precipitation should not be an important factor in the self-sealing of geothermal fields. Argillization appears to be an important shallow process. It is especially effective in the acid environment of many thermal shows, thus determining their migration and/or extinction. According to our analysis and to present evidence those three self-sealing processes are the most important ones. In The Geysers Field, the wells penetrated the same formation, the Franciscan graywackes, from top to bottom. The Franciscan Formation has a very low primary permeability; secondary or fissure permeability is at the contrary very high. It is evident that there is no recognizable cap-rock in the accepted sense of petroleum geology. The wells produce superheated steam; the producing zone begins at 300 m depth or so; the quantity of steam increases with the thickness of the producing zone penetrated by the holes. Beginning in 1964, the wells have been drilled with air as circulating medium. No steam or water has been observed in the top few hundreds meters drilled: we can safely conclude that the graywackes are impervious in the upper section of the holes. Cores and cuttings show frequent fissures filled with silica in different mineral forms and hydrothermally altered rocks are common. In the Geysers area, hot springs, steam vents, carbon dioxide and hydrogen sulphide fumaroles are numerous, and wide zones of rocks, altered by past hydrothermal activity, are prominent features. As usual in many hyperthermal areas, also in The Geysers the manifestations of surface heat change frequently in place, in size, and in fluids discharge. The filling of rock fissures by mineral deposition seems the simplest and most natural explanation of the place changes of the individual springs. The active faults continually generate new fissures, limit the sealing action, and account for the persistent surface thermal activity of the area. The composition of the waters from the hot springs at The Geysers has been re-considered, in comparison with both surface waters and natural steam. The hot springs mainly originate by natural steam condensation, as Allen and Day stated in 1927. This conclusion is now strenghtened and extended: the perched water table producing hot springs at The Geysers is purely condensed steam. Practically all its characteristics can be explained by this condition alone. Separation from other shallow water bodies is extremely sharp. Let us sumarize: the impermeability of the upper section of the holes is demonstrated by the lack of fluids in the Sulphur Bank area, whereas the geochemistry of the hot springs compared with shallow waters indicates that similar conditions occur in the Geysers and Little Geysers areas. Furthermore, silica and other fissure-filling processes occur all over the region, as well as argillization of graywackes. We conclude that:
- a)a cap-rock exists in The Geysers Field; this fact readily explains the production of dry steam; 相似文献