广西区域数字地震台网建设与发展     

姚宏  MOU Jianying 《华南地震》2011,31(4):29-38

进入21世纪以来,广西地震观测系统得到了迅速的发展.回顾了广西数字地震台网建设的发展历史,重点介绍了“十五”期间广西各级地震台网的建设情况,阐述了广西区域数字测震台网实现与邻省、地方和企业不同属性和类别的台网联网和数据共享后,地震监测能力获得了极大的提高过程.  相似文献   

Seismic wave propagation through material containing partially saturated cracks   总被引：2，自引：0，他引：2  

J. A. Hudson 《Geophysical Journal International》1988,92(1):33-37

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数字地震学的发展和展望     

陈祥熊 《福建地震》2003,(3)

本文简要介绍了地震观测仪器的重大变革 ,数字地震仪和模拟地震仪的联系和本质区别 ,宽频带地震学的含义 ,区域数字地震台网的任务以及数字地震学的发展的现状和应用前景。目的是供从事或将要从事数字地震学观测、分析和研究的同志参考。  相似文献   

The seismological picture of the inner core: structure and rotation     

Annie Souriau  Raphaël Garcia  Georges Poupinet 《Comptes Rendus Geoscience》2003,335(1):51-63

This paper presents a review of recent results concerning the structure and the rotation of the inner core, as inferred from seismological observations. We first focus on the apparent hemispherical pattern of the inner core structure, observed in both the anisotropy and the heterogeneity of the uppermost layers, whereas isotropic velocities seem to be homogeneous in a broad wavelength domain. Then we present results on the radial variations of the attenuation and its possible anisotropy, for which viscoelasticity and wave scattering provide complementary explanations. Linked to these results is a discussion about the detection of the PKJKP phase, which propagates as S-wave inside the inner core. Finally, the seismological observations of a possible inner core rotation are discussed; recent results seem to favour rotation rates below 0.2° yr^?1.  相似文献   

Systematic variations of mean travel-time residuals in space and time     

A. G. Prozorov 《Pure and Applied Geophysics》1977,115(3):675-692

Summary Mean travel-time residuals of P waves for the period 1964–1970 at stations in North America and Europe are well separated into large domains of positive and negative values. The spatial distribution of residuals in North America is in good agreement with the structure of the upper mantle obtained from Rayleigh wave dispersion and is in accord with magnitude anomalies and heat flow data. A systematic variation of residuals in time is found to be sensitive to major changes in the nature of the earthquake source distribution, as for example aftershocks, as well as to changes in methods of detection of first arrivals. Residuals at neighboring stations are correlated up to distances of the order of 2°. Half year mean residuals at stations within 2° distance from the epicenters of strong earthquakes have a sudden jump 1.5 years before the occurrence of an earthquake. A formal algorithm based on this pattern permits prediction of the times of all 16 earthquakes with magnitudeM7.5 occurring during the interval 1966–1972. Although the average duration of the alarm periods is about half the total time interval of the catalog, so that the algorithm has no practical importance, these results are statistically significant on a 99% level of confidence.  相似文献   

Variation ofb values before the Etnean eruption of March 1981     

S. Gresta  G. Patanè 《Pure and Applied Geophysics》1983,121(2):287-295

A fissural eruption occurred from the northern flank of Mt. Etna on March 17, 1981, and the associated earthquake activity, recorded by the seismic network operating on the volcano, was carefully examined to detect possible variations ofb values, according to the frequency-magnitude relationship, before the start of the eruption. The analysis of 4000B-type earthquakes was carried out according to the maximum likelihood method. A significant increase in theb value was noticed since the beginning of February 1981, followed by a sharp decrease in the days before the eruption started. The observed variation pattern was related to possible changes on the stress field acting on the volcano.  相似文献   

Transient disturbance produced in an elastic half-space by impulsive shearing traction distributed over a circular region     

N. C. Maiti 《Pure and Applied Geophysics》1978,116(1):198-211

The displacement produced in a semi-infinite, homogeneous, isotropic elastic medium by the application of shearing traction over a circular portion of the half-space has been evaluated in exact form by Cagniard's Technique (Cagniard, 1962;Gakenheimer andMiklowitz, 1969).  相似文献   

基于泊松分布的地震烈度发生概率模型   总被引：10，自引：1，他引：10  

高孟潭 《中国地震》1996,12(2):195-201

地震烈度发生概率和地震烈度超越概率都是衡量场地地震危险性的重要指标，地震烈度发生概率的计算民是人们比较关注的问题之定。本文根据目前工程地震和地震减灾研究中比较常用的Ｃｏｒｎｅｌｌ类地震活动性模型和反映地震时，空，强非均匀性的地震活动性模型，推导了场地地震烈度发生概率和计算表达式，通过计算实例，讨论了其与场地地震烈度极值概率（即超越概率差，通常被用来替代地震烈率发生概率）的差异，认为在一般情况下，两  相似文献   

Methods for Measuring Seismicity Rate Changes: A Review and a Study of How the M w 7.3 Landers Earthquake Affected the Aftershock Sequence of the M w 6.1 Joshua Tree Earthquake     

David Marsan  Suleyman S. Nalbant 《Pure and Applied Geophysics》2005,162(6-7):1151-1185

The development of fault interaction models has triggered the need for an accurate estimation of seismicity rate changes following the occurrence of an earthquake. Several statistical methods have been developed in the past to serve this purpose, each relying on different assumptions (e.g., stationarity, gaussianity) pertaining to the seismicity process.In this paper we review these various approaches, discuss their limitations, and propose further improvements. The feasibility of mapping robust seismicity rate changes, and more particularly rate decreases (i.e., seismicity shadows), in the first few days of an aftershock sequence, is examined. To this aim, the hypothesis of large numbers of earthquakes, hence the use of Gaussian statistics, as is usually assumed, must be dropped.Finally, we analyse the modulation in seismicity rates following the 1992, June 28 M_w 7.3 Landers earthquake in the region of the 1992, April 22 M_w 6.1 Joshua Tree earthquake. Clear instances of early triggering (i.e., in the first few days) followed by a seismicity quiescence, are observed. This could indicate the existence of two distinct interaction regimes, a first one caused by the destabilisation of active faults by the travelling seismic waves, and a second one due to the remaining static stress perturbation.  相似文献   

中国数字地震台网的数据在中国地震学研究中的应用   总被引：1，自引：1，他引：1  

周公威  陈运泰 《地震地磁观测与研究》1997,18(5):68-79

中国大陆邻近印度、欧亚和太平洋板块的边缘，其特点在于具有复杂的地壳构造和高地震活动性。中美合中国数字地震台网（ＣＤＳＮ）运行１０年来，在中国地震学研究中发挥了有效的作用。ＣＤＳＮ作为ＩＲＩＳ全球地震台网的参与伙伴，为全球地震学研究作出了贡献。本文概述了ＣＤＳＮ数据在中国地震学研究中的应用。  相似文献