The application of ultrasonic seismic model experiment in quality test of cement mortar injection of Yongjiang river submarine tun－nel tube foundation

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The idea and project of the “Medium－Scale Experiment Field for Earthquake Prediction”──Research on observations and applications of mining earthquake in Mentougou Coal Mine

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Seismic Risk Region Determination by Information Entropy

During the preparation process of a great earthquake, there are certain patterns of less randomness but more order in the space-time distribution of micro-earthquakes, which had been proved by seismic events and experiments. The information entropy concerning the dimension of the order in seismic distribution is systematically defined from the point of modern statistical physics in this paper. Relations of dynamic variations of information entropy with a strong shock occurrence time and the distribution of information with a strong shock occurrence place were approached through seismic data from the Wuqia, Xikar, Wushi, and Manasi regions in Xinjiang. It is indicated that before strong earthquakes, the value of information entropy often noticeably drops in seismic region, and generally much lower in the epicentral area than the surrounding regions. These two characters are of important significance in strong shock risk region determination and large shock tendency prediction.     

Earthquake-Generating Structure During the Period of the 1992 Sichuan Lima Earthquake Sequence

In this paper,a test or alternative scheme for studying large earthquake sequences through the study of small earthquake sequences is suggested,and a small earthquake sequence,the Lima earthquake sequence for which analogue records have been turned into digital data,is used here.In order to provide the deep construction background and the spatial distribution of structure for generating earthquakes,the P-wave and S-wave layered velocity models in this area are obtained by using mine explosion and earthquake observed records; then,the hypocenter locations and focal depths of the Lima earthquake sequence are determined adopting the velocity models given above and using a location method with numerical properties for a microseismic monitoring network(Zhao et al.,1994)and a new method for determining focal depth from data of a local seismographic network(Zhao,1992); finally,based on this,the variation of quality factor Q of the crustal medium during the period of the sequence is estimated.The obtained resul     

青岗坪金矿区折离断层系统的控矿作用

通过对青岗坪金矿区内发育的拆离断层系统的具体分析，揭示了其产生，发展的过程，对由其控制的几类金矿脉的形成机制进行了合理的探讨，并对不同的成矿阶段进行了划分。     

基于GIS的城市地震次生火灾蔓延初步研究——以福州市区为例

以W Arcview/GIS为工具 ,结合传统的火焰蔓延数学模型 ,发展了复杂系统条件下城市地震次生火灾蔓延的计算机仿真模型 ,并结合福州市主要建筑物结构类型的具体情况 ,提出了根据建筑物类型来区分不同可燃物类型的划分方案。结合火源、风向风力、可燃物分布等因素 ,该模型在地震时可用以判定某一时段内可能的延烧区域 ,估计地震次生火灾的灾害程度及其直接经济损失     

煤层顶板"两带"高度的微地震监测技术

主要介绍了中国和澳大利亚两个煤矿在长壁开采过程中的微地震监测成果，并进行了深入的理论分析和研究。该监测的主要目的是动态测定煤层开采过程中顶板岩石“两带”（冒落带和裂隙带）的发展规律和高度，以指导相邻采区留设合理的防水或防砂煤柱。观测结果表明：研究区域“两带”的最大高度均没有到达煤层上方的含水层，顶板突水的可能性非常小，这一结果与实际情况符合；同时也表明微地震监测是确定“两带”高度及设计防水和防砂煤柱的一种可靠手段。     

Experimental examination on the heterogeneity parameter C_v of earthquake precursors

Introduction Many earthquake cases indicate that there exists obvious heterogeneity in temporal-spatial distribution of earthquake precursors (FENG, 1983; MEI, et al, 1993). Therefore, it is very crucial for the study of earthquake prediction to describe the heterogeneity in temporal-spatial distribution of earthquake precursors and to understand its physical mechanism. Up to now, a lot of useful researches have been done in this field. Recently, WANG, et al (1999) and CHEN, et al (2000)…     

1976年唐山7.8级地震前各类地震前兆异常信息熵的场,源兆特征

利用“专家系统”的思想对每一地震前兆异常事件进行了综合评估，以每一异常的最可能发震时间计算发震概率，利用各类地震前兆异常群体信息熵研究了系统熵值与地震场，源兆的关系，分析了１９７６年唐山７．８级地震前各类地震前兆异常的时空分布特征，然后以唐山为中心在空间上划分三个区，近区，中间区和远区，分别计算了三个区各类地震前兆异常信息熵的时间演化值，分析了震前这种信息熵的场，源兆特征，震中近区的信息熵值要比中