闽南漳州沙建温泉区的微震观测   总被引：1，自引：0，他引：1       下载免费PDF全文

周立功  褚志贤 《地球物理学报》1989,32(2):178-190

1982年9-12月,在漳州温泉区布设了台网进行微震观测。结果表明,在漳州及其以北的沙建温泉区一带均有微震与小震群活动,震级为M_s=-1～1级,震源为3-14km。用震源的分布、震源机制解和微震综合断层面解的结果,研究了地质断裂的现今活动性及其与温泉的关系。认为区内东西向与北东向断裂是控制温泉分布的主要构造,而北西向断裂则是温泉的涌水构造。经探明,在有浅层热储的漳州市以及地质断裂发育的沙建地区,地震波速与介质泊松系数均低于正常值。此外,台网尚观测记录到一些异常的振动现象。根据地震的综合信息,探讨了研究区微震活动与水热活动的关系。  相似文献   

1988年澜沧—耿马地震的预报速报与对策     

姜葵  刘祖荫 《地震研究》1989,12(4):285-299

1988年11月6日,在云南省澜沧、耿马相继发生了7.6级、7.2级地震。这次地震前曾经作过准确的中长期预报。在1985年完成1986年出版的南北地震带未来十年地震危险性研究报告和预测图中,澜沧、耿马地区就是两个圈定的7级危险区中的一个。1986年该报告正式上报云南省人民政府。1987年起该区域为我省的地震危险性监视区。1988年除加强监视外,我们还加强了一系列大震对策措施的准备工作。1988年8月该区地震活动增强,我局派出的现场考察组向当地政府作了汇报,并指出该区仍存在着严重的地震危险性。与此同时,省局科技人员对该区作出了一系列不同程度的短期预报,并向当地打了招呼,当地政府采取了一定的措施。遗憾未能作出临震预报。大震发生后,我局昆明遥测台网仅7分钟定了位置和震级,并报告了国家地震局和省政府,及时为抗震救灾提供可靠的科学依据。震后2.5小时,现场监测队伍就出发了。在大震现场仅三天内就作出了地震趋势判断,也较好地作出了强余震的预报,有力地组织了地震考察及地震知识宣传。这一系列的大震对策工作极大地推动了现场的抗震救灾工作,减轻了震灾的继续发生及其带来的巨大的心理和社会影响。整个澜沧—耿马地震的预报、速报及大震对策工作在国内外都是一次较高水平的科学实践,得到了中央慰问团及  相似文献   

模糊数学方法在分析日本东海地区地震前兆中的应用     

冯德益  市川政治 《地震研究》1989,12(4):360-369

本文把模糊模式识别的直接方法用于检测日本东海地区地震活动性、体积应变、地下水位、地下水氡含量、地倾斜和潮位中的前兆变化。此方法可消除诸如降雨和气温变化等干扰,使我们能更清晰地识别出地震前兆。此外,还把模糊相似方法和模糊聚类方法应用于识别地震空区及检验地震活动随时间变化的相似性。上述方法在日本其他地区同样有效,即将编入日本气象研究所板内地震预报计划中的计算机系统内。  相似文献   

Correlation of foreshocks and aftershocks and asperities     

Vindell Hsu  Charles E. Helsley  Eduard Berg  David A. Novelo-Casanova 《Pure and Applied Geophysics》1984,122(6):878-893

A close correlation in spatial distribution of local seismic activity and energy release patterns before and after the 1979 Petatlan, Mexico earthquake suggests heterogeneity within the fault plane of this major low-angle thrust event associated with subduction along the Middle America Trench. A simple two-asperity model is proposed to account for the complexity. Foreshocks and aftershocks of the neighboring 1981 Playa Azul earthquake showed a similar pattern. As both events occurred at the junction of the Orozco Fracture Zone and the Middle America Trench, we speculate that the observed complex fault plane is caused by subduction of the rugged ocean floor of the Orozco Fracture Zone. Short-term precursory seismicity prior to the Petatlan earthquake can be explained by using the asperity model and migration of a slip front from the south-east to the north-west across the main shock source region.  相似文献   

Anomalous hydrogen emissions from the San Andreas fault observed at the Cienega Winery,central California     

Motoaki Sato  A. J. Sutton  K. A. McGee 《Pure and Applied Geophysics》1984,122(2-4):376-391

We began continuous monitoring of H₂ concentration in soil along the San Andreas and Calaveras faults in central California in December 1980, using small H₂/O₂ fuel-cell sensors. Ten monitoring stations deployed to date have shown that anomalous H₂ emissions take place occasionally in addition to diurnal changes. Among the ten sites, the Cienega Winery site has produced data that are characterized by very small diurnal changes, a stable baseline, and remarkably distinct spike-like H₂ anomalies since its installation in July 1982. A major peak appeared on 1–10 November 1982, and another on 3 April 1983, and a medium peak on 1 November 1983. The occurrences of these peaks coincided with periods of very low seismicity within a radius of 50 km from the site. In order to methodically assess how these peaks are related to earthquakes, three H₂ degassing models were examined. A plausible correlational pattern was obtained by using a model that (1) adopts a hemicircular spreading pattern of H₂ along an incipient fracture plane from the hypocenter of an earthquake, (2) relies on the FeO–H₂O reaction for H₂ generation, and (3) relates the accumulated amount of H₂ to the mass of serpentinization of underlying ophiolitic rocks; the mass was tentatively assumed to be proportional to the seismic energy of the earthquake.  相似文献   

The Chemical Composition of Global Subducting Sediments and Its Geological Significance     

Renjie Zhao  Quanshu Yan  Haitao Zhang  Yili Guan  Zhenmin Ge  Long Yuan  Shishuai Yan 《地球科学进展》1986,35(8):789-803

Subducted sediments play an important role in crust-mantle interaction and deep mantle processes, especially for subduction zone magmatism and mantle geochemistry. The current rate of Global Subducting Sediments (GLOSS) is 0.5~0.7 km³/a. The GLOSS are composed of terrigenous material(76 wt.%), calcium carbonate(7 wt.%), opal(10 wt.%) and mineral-bound H₂O⁺(7 wt.%). The chemical compositions of GLOSS are similar to those of upper continental crust which is mainly controlled by the terrigenous materials, and yet the materials formed by marine processes will dilute the terrigenous materials. The components of subducted sediments are different among trenches. In the accretionary margin, the components of subducted sediments are similar to those of the upper crust, while in the non-accretionary margin the components are terrigenous materials plus those produced by marine processes. During subduction, subducted sediments will released fluids, melt or supercritical fluid to affect island arc/back-arc basin magmatism by means of aqueous fluid or sediment melt. In addition, a part of subducted sediments, together with underlying altered oceanic crust/lithosphere, recycle into the mantle and contribute to the mantle heterogeneity. Geochemical tracers indicate that subducted sediments play variable contributions to the magmatic processes in different tectonic setting. Thus, subducted sediments play an important role in two relatively independent dynamics systems (plate tectonics and mantle plume), as well as related mantle evolution models. As a result, by accurately calculating the compositions of subduction sediments and using various geochemical indicators, we can further limit the input and output fluxes of various elements or isotopes, and then obtain more accurately residual subducted components, which can provide us some important clues for geodynamic process.  相似文献   

诸广花岗岩体放射性水异常的某些特征     

吴敬炳 《华东地质学院学报》1986,(2)

本文以寻找铀矿为目的,在该岩体140Km~2面积上进行水化学普查,发现水异常370个,其特征为:若异常多且成片出现,则预示着有单个矿体规模不大的矿体群存在;条带状展布的水异常预示着存在方向相同的矿化带;阻水阻气构造带近旁之异常预示水源上方存在矿化;水温偏高之水异常与矿化关系密切;与矿化有关的多为铀—氡混合异常;大构造处之水异常并不表示此构造存在矿化,面往往是在其附近次一级构造中成矿.  相似文献   

利用近场地震加速度记录测定近震震级ML的研究     

章文波  彭克中 《地震工程与工程振动》1995,15(3):4-11

本文对如何利用强震加速度记录测定近震震级ＭＬ的问题进行了研究，指出了在我国所使用的原始量规函数存在着系统偏差，并用回归现有观测资料的方法修正了这种系统偏差。用修正后的量规函数，利用近场加速度记录计算的ＭＬ值同微震台网所测定的值符合得较好，说明本文所提出的方法是可行的。  相似文献   

加卸载响应比理论在中强地震（7〉M≥6）预测中的应用   总被引：6，自引：2，他引：6  

陈学忠  尹祥础 《中国地震》1995,11(1):33-37

本文运用加卸载响应比理论对中强地震前的加卸载响应比的变化进行了研究。结果表明，中强地震前加卸载响应比明显上升，表现为三种不同的形态，持续时间为半年到两年。  相似文献   

区域震相强度比—岩石层热状态的有效指示     

高世玉  张廉强 《中国地震》1995,11(3):204-211

本文根据白家疃台６０年代以来的短周期地震记录图，分析了区域震相的强度比。研究表明：Ｓｎ／Ｌｇ波的强度比波传播路径上岩石层热结构、热状态及强地震活动等均有相关性，并就这种相关性对于强地震成因及其预测研究的直接意义进行了讨论。  相似文献