尾波振幅比和能量比异常特征研究     

尹志文  李萍 《高原地震》2001,13(4):47-51

利用中国数字地震台网（CDSN）兰州台记录的短周期数字地震资料，测定了尾波最大振幅与S波最大振幅之比r1、尾波能量与S波能量之比的平方根值r2随时间的变化。结果表明：在永登主震（19950和天祝-古浪主震（1996）前，r1和r2均出现上升或下降异常变化，且有较大的偏离平均值的异常高值或异常低值出现。  相似文献   

云南地区双震型地震序列中第二主震的前震识别     

蔡静观  雷素华 《地震研究》1995,18(2):117-124

本文通过对双震型地震序列的地震波动力学特征的研究，提出了识别双震中第二主震前震的可能性。结果表明、在双震第一主震发生后，序列地震的Ｐ波垂直分量初动一致时，可依据波形来识别第二主震的前震；而初动不一致时有三种情况：１、两组初动中有一组Ｐ、Ｓ波振幅比仍保持为过原点的直线而另一组离散，２、两组初动的振幅比分别为过原点的直线；３、两组初动的振幅比共同组成过原点的直线，对前两种情况可识别第二主震的前震，最后一种情况难以识别。总体达６０－７０％的可识别率。  相似文献   

Inversion of the Strain Accumulation State in Crustal Interior from Observations of Earth Tide Tilts     

Wu Yilin  Li Ping  Chen Guangqi  Li XudongInstitute of Seismology  SSB  Wuhan  China 《中国地震研究》1994,(4)

The strain accumulation state in crustal interior and its migration trend can be inverted from observational data of earth tide tilts.In China,large earthquakes frequently occur in the border area between Yunnan and Sichuan Provinces.Using the observational data for years from 7 stations in this area,γ(the amplitude factor of earth tide tilts)values that characterize the strain accumulation state in crustal interior have been inverted in this paper.It has been found out that,Ms>5 events in the area often occur when γreaches an anomaly value.Using the time-space collocational stereomodelling the migration trend of strain accumulation can be determined to make a prediction for the probable location of a forthcoming earthquake in the area.  相似文献   

中强震前单台地震波振幅比异常特征   总被引：2，自引：0，他引：2  

杨欣  敖雪明 《华南地震》1994,14(4):22-28

通过对乌鲁木齐、石场和库尔勒地震台十几年来地震波振幅比的系统追踪研究，发现在中强地震前，振幅比无论是在空间分布还是在时间进程上都显示出比较明显的异常变化特征。研究结果表明，当监测范围内的孕震介质发生变化时，单台地震波振幅比可以反映出介质的异常变化过程，该方法具有一定的预报效能。  相似文献   

陕西地区震源参数和平均应力场的研究   总被引：2，自引：0，他引：2  

杜兴信  张春生 《四川地震》1994,(2):6-11

利用陕西地区地震台网记录的小震垂直分量最大振幅比测定了陕西地区的震源参数，并用其小震断层面解反演了平均应力场。结果表明，陕西地区最大主压应力方向为北东东向，倾角中等，相对中等主压应力较大，小震断层面呈北西和北东向优势分布。分区试验表明，关中地区与全省基本一致，陕南似乎存在较大差异，其最大主压应力方向为北北西一南南东方向，中等主压应力也相对较小。  相似文献   

A study on the duration and amplitude characteristics of earthquake ground motions   总被引：2，自引：0，他引：2  

Y. Shoji  K. Tanii  M. Kamiyama 《Soil Dynamics and Earthquake Engineering》2005,25(7-10):505-512

The duration, total power, rms amplitude, and peak ground acceleration (PGA) are examined using the data from the KiK-net digital borehole accelerograph arrays in Japan during three large earthquakes. We investigate correlations between the duration, PGA on the surface and hypocentral distance, instrumental seismic intensity, and the local site conditions. Also considered in this paper, are correlation between the duration and PGA. This present study suggests that PGA is inversely proportional to the duration.Comparing the duration, total power, rms amplitude, and PGA on the surface with those at the bottom of borehole, the duration and maximum amplitude characteristics of earthquake ground motions are investigated with emphasis on site amplification due to the local site conditions. The difference of amplification factors is not only site-dependent but also event-dependent. The comparison of the site amplification factors and the average shear-wave velocity in the upper 30-m showed a good agreement.This paper indicated that the duration and amplitude characteristics suffer a reciprocal effect due to the local site conditions and the site dependency of maximum amplitude PGA is greater than that of the duration. In view of the results, the duration is not less important than the maximum amplitude and frequency content in earthquake engineering. Moreover, this study provided meaningful information of input motion available to earthquake-resistant design.  相似文献   

强振幅地震属性分析技术在车排子地区油气检测中的应用   总被引：3，自引：1，他引：3  

王离迟  洪太元  江洪 《新疆地质》2006,24(3):310-313

准噶尔盆地西缘车排子地区是目前中石化的有利探区,P2井的突破,加速了该区油气勘探的步伐.为了提高勘探的经济效益,用地震特殊处理手段对有利目标进行预测就显得非常重要和迫切.本文运用强振幅属性分析技术有效地预测了该区的有利目标区,并经实钻证实.强振幅属性分析技术是目前车排子地区油气检测的有效手段.  相似文献   

Strong, localised country-rock contamination and partial homogenisation of a mafic magma: An example from west central Sweden     

Anders Lindh  Anders Kjllerstrm  Zoltan Solyom 《Lithos》2006,86(3-4):212-228

A dolerite sill cutting slightly older basalt in west-central Sweden shows a strong chemical variation (54% < SiO₂ < 73%) within a restricted area (< 100 × 100 m²). The linear correlation among almost all elements is extremely high; in addition, _NdT is strongly correlated with the SiO₂ content. Least-square hyperbolic-ratio and three-element ratio modelling (common denominator) suggests that most of the chemical variation is explained by mixing and/or micro-mingling. In all, we test 407 hyperbolas, of which 402 are fitted. The five ratio pairs, which could not be fitted to a hyperbola using a least-square fitting procedure, have the ratio Th / Eu in common. Testing the goodness of fit is problematic for hyperbolic distributions; for comparing purposes we sum the distances to chords approximating the hyperbola. Mobile and immobile elements behave similarly, suggesting that no elements are lost or added from outside the system. The data suggests that already the most mafic of the analysed rocks is a mixture of the ‘normal’ dolerite and a siliceous crustal rock. A mafic magma intruded into the base of the crust, where it fractionated resulting in a decreased Mg number. The magma was then contaminated with country rocks in an intermediate magma chamber due to country rock melting; during mixing/mingling almost no fractionation took place. The contaminated rock suggests the presence of a fluid phase. This was probably a prerequisite for country-rock melting. Enrichment in some incompatible elements suggests that besides major mixing/mingling a thermochemical separation process has affected the most felsic rock enriching it in light rare earths and Zr.  相似文献   

γ射线康普顿背散射扫描仪测量的信噪比研究   总被引：1，自引：0，他引：1  

童利标  丁厚本 《CT理论与应用研究》1998,(1)

本文详细给出了ＣＢＳ测量中噪声的物理来源和降低噪声的有效措施,还对信噪比进行了定量的分析和讨论。  相似文献   

Prediction method of sand-movement direction in rivers by geochemical elements     

K. Mizumura  T. Nishimoto  Y. Kumagai  T. Yamamoto 《Environmental Geology》1996,28(2):88-98

 The analysis of sand samples by X-ray fluorescent spectroscopy (XRF) gives the ratio of the geochemical elements to construct the sand samples. The application of the ratio matching to sand samples represents the correlation number between two sand samples with respect to geochemical elements. When the correlation number between two sand samples is low, the two samples are not geochemically similar each other. This denotes that the exchange of sand between two sampling points is scarce or the two samples are independent. When the correlation number between two sand samples is high, the two samples are geochemically similar, signifying that the exchange of sand between two sampling points is frequent or there is sand movement between two sampling points. If there exists prominent sand movement in the study area, the correlation number is almost 1 and kilo count number per second of each geochemical element per weight decreases along the flow direction. The decrease is caused by the reduction of sizes and the adherence of dirt on the surface of sand particles. Since the flow direction in rivers is usually the same as the direction of sand movement, it can be verified. This study obtains satisfactory results applying the method of prediction in sand movement to sediments in rivers. Received: 17 May 1995 · Accepted: 14 August 1995  相似文献