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地震活动性参数分类及其相关性初步研究 总被引:9,自引:0,他引:9
从各地震活动性参数的原始定义及其计算过程所反映出的物理本质出发,并为研究不同参数间相关性方便,将已有的30多种地震活动性参数分为五类:频度类、能量类、分布类、综合类和非线性类。在过去工作的基础上,进一步研究了同一类别中各参数间的相关性,取得了一些初步看法。 相似文献
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Though the forecast and prediction of earthquakes is a commonly accepted difficult problem in science, the step towards the exploration and knowledge of the generation and occurrence of earthquakes has never stopped. It has strong scientific exploration nature and great social efficacy in disaster reduction. For this reason, it has always been the object and motivation pursued assiduously by earthquake researchers. It is beyond doubt that the study of seismicity is still one of the important information sources that have historical records of the longest time and most abundant earthquake cases that can be testified. For many years, with the progress of study in this aspect and the unceasing increase of study methods, there have been not less than tens of methods that can be used to describe theseismicity characteristics from different angles. It is of great importance to determine from the numerous methods those ones that are relatively independent and to understand how many dimensions are there to restrict the complexsystem of earthquake generation and occurrence. Taking these as a referential basis, we would be able to identify the quantities that restrict the study of the seismogenic system, to raise the scientific value and rigorousness of prediction and forecast, and to get rid of the trouble of repeated information superposition. 相似文献
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Mathematicalmodellingofnonlinearbehaviourofseismicity杨立明,石特临,郭大庆Li-MingYANG;Te-LinSHIandDa-QingGUO(EarthquakeResearchInstitut... 相似文献
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Assessing current faulting behaviors and seismic risk of the Anninghe-Zemuhe fault zone from seismicity parameters 总被引:6,自引:0,他引:6
Introduction Strong and large earthquakes are prepared and generated on specific segments of active fault zones, especially on the asperity parts of the zones (Aki, 1984; Wiemer, Wyss, 1997; Wyss, et al, 2000). Therefore, both the faulting-behavior identification and the rupture segmentation mainly based on the method of active tectonics are always important aspects in active fault research (DING, et al, 1993). The purposes of the two aspects of research focus on determining fault units tha… 相似文献
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TheapplicationofseismicdatawithdifferentprecisioninthedeterminationofseismicityparametersXue-ShenJIN(金学申);Ying-HuaDAI(戴英华);Ju... 相似文献
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东北地震活动性短期预报方法研究 总被引:1,自引:1,他引:1
研究了1970年以来东北地区发生的MS≥5·0浅源地震孕育过程中地震活动性参数和地震活动图像的变化特征,并对地震活动性参数进行了比较系统地综合预报效能评价,结果显示:东北9次(组)浅震地震前,所研究的5项地震活动性参数中,88·9%出现了持续3个月以上的短期异常变化,且5项参数R值评分结果都满足97·5%的置信水平;88·9%地震前震源区附近出现了孕震空区,有87·5%孕震空区在空区边缘或空区内部出现了ML≥4·0逼近地震,逼近地震以单个或成对的形式出现。66·7%的地震在震源区附近出现了地震条带异常。最后给出东北地区中强震的短期预报方法,这对未来东北地区的地震预报工作将起着一定的参考意义。 相似文献
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In the paper, we have discovered the abnormal area distribution features of maximum variation values of ground motion parameter uncertainty with different probabilities of exceedance in 50 years within the range of 100°~120°E,29°~42°N for the purpose to solve the problem that abnormal areas of maximum variation values of ground motion parameter uncertainties emerge in a certain cities and towns caused by seismicity parameter uncertainty in a seismic statistical region in an inhomogeneous distribution model that considers tempo-spatial nonuniformity of seismic activity. And we have also approached the interrelation between the risk estimation uncertainty of a site caused by seismicity parameter uncertainty in a seismic statistical region and the delimitation of potential sources, as well as the reasons for forming abnormal areas. The results from the research indicate that the seismicity parameter uncertainty has unequal influence on the uncertainty of risk estimation at each site in a statistical region in the inhomogeneous distribution model, which relates to the scheme for delimiting potential sources. Abnormal areas of maximum variation values of ground motion parameter uncertainty often emerge in the potential sources of Mu≥8 (Mu is upper limit of a potential source) and their vicinity. However, this kind of influence is equal in the homogeneous distribution model. The uncertainty of risk estimation of each site depends on its seat. Generally speaking, the sites located in the middle part of a statistical region are only related to the seismicity parameter uncertainty of the region, while the sites situated in or near the juncture of two or three statistical regions might be subject to the synthetic influences of seismicity parameter uncertainties of several statistical regions. 相似文献
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魏富胜 《地震地磁观测与研究》1993,14(2):42-48
简要回顾了地震活动性定量化研究的进程,概述了各综合定量指标参量的特点,介绍了地震活动度 S 及其在定量描述地震活动性中的某些应用成果,展望了 S 应用于地震监测预报中的可能性。 相似文献
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在系统研究洞庭湖区地震活动与地质构造关系的基础上,讨论了历史地震和近代地震的空间分布、时间序列和活动周期,预测了洞庭湖区近年的地震活动趋势。 相似文献
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Mario Octavio Cotilla Rodriguez 《Journal of Seismology》1998,2(4):323-335
The seismicity of Cuba is briefly presented together with a few fundamental neotectonic elements of the adjacent Caribbean region. The Cuban seismicity catalogue has been extended back to 1528 and it shows that the largest earthquakes occurred in 1766 and 1852 (I = IX MSK). Two types of seismicity (intraplate and interplate) can be distinguished in Cuba. Western and Eastern Seismotectonic Units correspond to intraplate type and the Southeastern Seismotectonic Unit to interplate type. Western Cuba is characterized by a low frequency of earthquake occurrence. Distribution of epicenters is not regular and the most important events mainly concentrate along two regional active fault system (Nortecubana and Surcubana). Due to the lack of seismic stations in this region, the characterization of seismicity is frequently done on the grounds of historical data available from 1693. The main seismogenic source for Cuba is the Bartlett-Cayman fault system, but inland there are other active structures. Some issues about historical and present day Cuban seismological research are also showed. 相似文献
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Pradeep Talwani 《Pure and Applied Geophysics》1995,145(1):167-174
The cause for continuous induced seismicity at Koyna is not well understood. A heuristic model based on various physical parameters observed at Koyna is being proposed to explain the ongoing seismicity. This model contains two essential elements: (i) Intersecting faults near Koyna provide means of stress build-up in response to plate tectonic forces. (ii) The annual reservoir loading cycle and changes in the ground water table perturb this stress build-up by an influx of pore pressure in a fluid infiltrated medium. Hence, the spatial and temporal pattern of the pore prussure distribution and the seismicity will be governed by the location and hydromechanical properties of the faults and fractures. The predictions of the model can be tested by comparing the temporal and spatial pattern of seismicity with the changes in lake level and water table. 相似文献
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根据晋冀蒙交界近33年的区域台网地震资料,运用最大似然法,分别计算并绘制晋冀蒙交界1980年、1990年、2000年以来 b 值空间扫描图像,结果显示,低 b 值异常区主要分布在大同、张北、代县一带。依据区域地质构造条件、b 值空间分布图像、历史强震和现代地震活动特征,将晋冀蒙交界分成张北段、延庆段、大同段和代县段4个段落,采用最佳效果拟合法+最大似然法,对各段落进行 b 值时间扫描,并且利用断裂带分段的多地震活动参数值组合分析方法,分析4个段落的现今活动习性,综合判定处于相对高应力和闭锁状态的断裂段。研究结果表明,张北段处于高应力背景下的相对闭锁状态,但会受到1998年、1999年张北 M 6.2、M 5.6强余震影响。综合分析认为,需注意张北段和延庆段发生中强地震的长期地震危险。 相似文献
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Subduction induced compressional stress, lateral displacement faults probably linked to the NW extension of the Polochic-Motagua fault system, and local magma emplacement create a complex geological setting for the El Chichon volcano.Gravity analysis reveals that the principal structures in the area correspond to synclines and anticlines. Downward continuation of the gravity field suggests the presence of magma emplacement SE of the volcano. This magmatic emplacement appears to be the principal cause of the truncation of the syncline in which the volcano lies.Analyses of earthquakes occurring after eruptions show that the vertical distribution of events is confined to a roughly cylindrical zone which correlates well with the region of magmatic emplacement inferred from the gravity analysis.Even though more than 350 km separate the volcano from the Middle American trench, the compressional stress regime reported for the area may correlate with subduction stress (N30°E). However, the strike direction for the principal faults in the zone, N60°W, permits us to postulate that the NW extension of the Polochic-Motagua fault system is implicated in the local tectonics of the El Chichon area. 相似文献
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Michael E. Wysession Emile A. Okal Kristin L. Miller 《Pure and Applied Geophysics》1991,135(2):261-359
We establish here a comprehensive database of intraplate seismicity in the Pacific Basin. Relocation and analysis of 894 earthquakes yield 403 reliable intraplate earthquakes during 1913–1988. These numbers do not include earthquake swarms, which account for another 838 events. Most of the remainder (304 events) are actually plate boundary earthquakes that have been erroneously located in intraplate regions. A significant number occur in recent years when location capabilities should have guarded against this situation. Relocations involve a careful linear inversion ofP andS arrivals, accompanied by a Monte Carlo statistical analysis. We have also attentively removed the high number of clerical errors and nuclear tests that exist in epicenter bulletins.A geographical examination of the relocated epicenters reveals several striking features. There are three NW-SE lineaments north of the Fiji Plateau and in Micronesia; diffuse seismicity and incompatible focal mechanisms argue against the southernmost, discussed byOkal
et al. (1986) andKroenke andWalker (1986), as the simple relocation of the Solomon trench to the North. Besides another striking lineament, along the 130°W meridian, there is also a strong correlation between seismicity and bathymetry in certain parts of the Basin. In the Eastcentral Pacific and Nazca plates there are many epicenters on fracture zones and fossil spreading ridges, and hot spot traces like the Louisville, Nazca and Cocos Ridges also display seismicity. 相似文献
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Spatial and temporal distribution of seismicityoccurring prior to the Umbria-Marche earthquake ofSeptember 26, 1997, are studied. By applying the RTLprognostic parameter, a quiescence stage followed bya period of foreshock activation is observed beforethe event. The main shock occurred soon after therecovery of the RTL parameter to its normal backgroundlevel. An investigation of the clustering process isperformed on the earthquakes with M 3.5,occurred since 1989 in the area of the epicenter ofthe September 26, 1997 event. In comparison to theaverage background of the previous period, theincrease of the area of rupture activated during thetwelve months leading up to the Umbria-Marcheconcentrates in the vicinity of the main shock. Someresults of application of the time-to-failure model toseismicity before the Umbria-Marche main shock, arealso discussed. 相似文献
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In this study we investigate present-day seismicity and crustal deformation of Egypt based on a comprehensive earthquake catalog
from 1900 to 2004 by focal mechanism stress inversion and by recent GPS observations. Spatial distribution of earthquake epicenters
indicates that Egypt has been suffered from both interplate and intraplate earthquakes. Most earthquake activity (more than
70%) has been concentrated in northern Egypt along the geologically documented borders of Sinai subplate (northern Red Sea
and its two branches Suez rift and Aqaba–Dead Sea transform). The majority of inland earthquake focal mechanisms in Egypt
are normal with strike-slip component or strike-slip faulting events. Only a small minority, namely four events, exhibits
reverse faulting. The inversion method of Gephart and Forsyth (1984) was applied to calculate the orientation of the principle
stress axes and the shape of the stress tensor. The best fitting tensor in Egypt shows homogeneity stress field. The tension
stress regime is dominant in northern Egypt. The stress directions are well resolved by the 95% confidence limits, the relative
stress magnitude has a value of about 0.3. However, along southern Egypt the strike-slip regime is dominant. The shape factor
(R-value) is 0.5, which means that the deviatoric components of σ1 and σ3 are of the same magnitude, but of opposite signs. The average horizontal velocity of GPS stations in Egypt is 5.15± 1.1 mm/year
in mostly NNW direction. The results of deformation analysis indicate that the northern Egypt is deformed more than the southern
part. Only the Egyptian-Mediterranean coastal–Nile Delta zone dominates as a compression deformation area. However, an extensional
deformation has been observed throughout the rest of country. This means that the relative motion of African plate with respect
to both Eurasian and Arabian has highly controlled the deformation processes in Egypt. 相似文献