Experimental study on the relation between the water content of surface soil and theacoustic wave

Introduction Earthquake is not an isolated event. The focal region is not a closed system either. It is able to exchange energy or material with the medium outside this region. These kinds of exchange may cause various physical and chemical effects, so it is possible to get precursory signals by using space remote sensing technology. Many scholars (QIANG, et al, 1990; GENG, et al, 1992; XU, et al, 1995) have carried out some preliminary researches and experiments on the mechanism of therm…     

The crustal micro-deformation anomaly and the credible precursor

What is a credible seismic precursor in observation of deformation? A real seismic precursor ought to be resulted from the variations in the earth strain and stress. The deformation observation can provide the information during earthquake gestation and occurrence period for us. Usually the seismic precursors can be divided into field and epicentral region precursors. The precursor information is very useful for seismic prediction from epicentral region or near epicentral region. Micro-deform…     

Relation between electricity structure of the crust and deformation of crustal blocks on the northeastern margin of Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau was formed by coales-cence of microcontinents of different geologic histo-ries, i.e. it consists of a series of blocks, such as Hi-malayas, Lhasa, Qiangtang, Kunlun, Qaidam and Qi- lian blocks from south to north. The blocks moved firstly in the NNE direction, then in the NE direction and at last in the ENE or E-W direction from south to north by a combined action of Indian Plate moving northward and obstruction of Tarim and other blocksnorth of the plateau. T…     

On the colocation iterative solution model and algorithm for gravity anomaly

ＯｎｔｈｅｃｏｌｏｃａｔｉｏｎｉｔｅｒａｔｉｖｅｓｏｌｕｔｉｏｎｍｏｄｅｌａｎｄａｌｇｏｒｉｔｈｍｆｏｒｇｒａｖｉｔｙａｎｏｍａｌｙＹＵＡＮ－ＸＩＹＡＮＧ（杨元喜）ａｎｄＣＨＡＮＧ－ＪＩＡＮＬＩＵ（刘长建）ＺｈｅｎｇｚｈｏｕＩｎｓｔｉｔｕｔｅｏｆＳ...     

Study on the pattern and mode of vertical crustal deformation during the seismogenic process of intraplate strong earthquakes

Ｓｔｕｄｙｏｎｔｈｅｐａｔｔｅｒｎａｎｄｍｏｄｅｏｆｖｅｒｔｉｃａｌｃｒｕｓｔａｌｄｅｆｏｒｍａｔｉｏｎｄｕｒｉｎｇｔｈｅｓｅｉｓｍｏｇｅｎｉｃｐｒｏｃｅｓｓｏｆｉｎｔｒａｐｌａｔｅｓｔｒｏｎｇｅａｒｔｈｑｕａｋｅｓ杨国华,桂昆长,巩曰沐,杨春花,韩...     

Features of isostatic gravity anomaly and seismic activity in the Central Asian region

Ｆｅａｔｕｒｅｓｏｆｉｓｏｓｔａｔｉｃｇｒａｖｉｔｙａｎｏｍａｌｙａｎｄｓｅｉｓ┐ｍｉｃａｃｔｉｖｉｔｙｉｎｔｈｅＣｅｎｔｒａｌＡｓｉａｎｒｅｇｉｏｎＳＨＥＮＧ－ＭＩＮＧＦＡＮＧ１）（方盛明）ＲＵＩＦＥＮＧ２）（冯锐）ＣＨＡＮＧ－ＺＨＥＮＧＴＩＡＮ...     

Features of fractal dimension anomaly of radon content in underground water in North China before and after the 1976 Tangshan earthquake

ＦｅａｔｕｒｅｓｏｆｆｒａｃｔａｌｄｉｍｅｎｓｉｏｎａｎｏｍａｌｙｏｆｒａｄｏｎｃｏｎｔｅｎｔｉｎｕｎｄｅｒｇｒｏｕｎｄｗａｔｅｒｉｎＮｏｒｔｈＣｈｉｎａｂｅｆｏｒｅａｎｄａｆｔｅｒｔｈｅ１９７６ＴａｎｇｓｈａｎｅａｒｔｈｑｕａｋｅＣｈａｎｇ－Ｃｈｕ...     

The relation between the response spectrum and the phase diference spectrum

ＴｈｅｒｅｌａｔｉｏｎｂｅｔｗｅｅｎｔｈｅｒｅｓｐｏｎｓｅｓｐｅｃｔｒｕｍａｎｄｔｈｅｐｈａｓｅｄｉｆｅｒｅｎｃｅｓｐｅｃｔｒｕｍＦＥＮＧ－ＸＩＮＺＨＡＯ（赵凤新）ａｎｄＹＵ－ＸＩＡＮＨＵ（胡聿贤）ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，Ｓｔａ...     

Nonlinear interactions between gravity waves and tides

In this study, we present the nonlinear interactions between gravity waves (GWs) and tides by using the 2D numerical model for the nonlinear propagation of GWs in the compressible atmosphere. During the propagation in the tidal background, GWs become instable in three regions, that is z = 75―85 km, z = 90―110 km and z = 115―130 km. The vertical wavelength firstly varies gradually from the initial 12 km to 27 km. Then the newly generated longer waves are gradually compressed. The longer and shorter waves occur in the regions where GWs propagate in the reverse and the same direction of the hori-zontal mean wind respectively. In addition, GWs can propagate above the main breaking region (90—110 km). During GWs propagation, not only the mean wind is accelerated, but also the amplitude of tide is amplified. Especially, after GWs become instable, this amplified effect to the tidal amplitude is much obvious.     

The method of AF synthetic detection on crust deformation anomaly and its applica-tion in earthquake

ＴｈｅｍｅｔｈｏｄｏｆＡＦｓｙｎｔｈｅｔｉｃｄｅｔｅｃｔｉｏｎｏｎｃｒｕｓｔｄｅｆｏｒｍａｔｉｏｎａｎｏｍａｌｙａｎｄｉｔｓａｐｐｌｉｃａ－ｔｉｏｎｉｎｅａｒｔｈｑｕａｋｅｐｒｅｄｉｃｔｉｏｎＡＮ－ＦＵＮＩＵ（牛安福）ＸＵ－ＤＯＮＧＬＩ（李旭东）ＪＩ...     

Surface deformation and gravity changes caused by dilatancy in a layered elastic-vis-coelastic half space

Ｓｕｒｆａｃｅｄｅｆｏｒｍａｔｉｏｎａｎｄｇｒａｖｉｔｙｃｈａｎｇｅｓｃａｕｓｅｄｂｙｄｉｌａｔａｎｃｙｉｎａｌａｙｅｒｅｄｅｌａｓｔｉｃ┐ｖｉｓ┐ｃｏｅｌａｓｔｉｃｈａｌｆｓｐａｃｅＹＯＮＧＷＡＮＧ（王勇）ＨＯＵＴＳＥＨＳＵ（许厚泽）Ｉｎｓｔｉｔ...     

Precision calculation of crustal deformation induced by radial steady laminellar flow of underground water from single well in multi-layered structural aquifers

Ｐｒｅｃｉｓｉｏｎｃａｌｃｕｌａｔｉｏｎｏｆｃｒｕｓｔａｌｄｅｆｏｒｍａｔｉｏｎｉｎｄｕｃｅｄｂｙｒａｄｉａｌｓｔｅａｄｙｌａｍｉｎｅｌａｒｆｌｏｗｏｆｕｎｄｅｒｇｒｏｕｎｄｗａｔｅｒｆｒｏｍｓｉｎｇｌｅｗｅｌｉｎｍｕｌｔｉ┐ｌａｙｅｒｅｄｓｔｒｕｃ...     

山西断裂带的地震活动与形变资料分析研究

用地震活动性和水平形变资料及定点地倾斜资料分析构造活动中岩层物理变化与形变位移之间对应关系,对以后GPS观测的形变应用于地震预报做一些尝试性工作。结果表明,GPS资料应用于地震预报是大有前途的。     

Present-day seismicity,stress field and crustal deformation of Egypt

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.     

Study on scale dependence of strain value obtained from crustal deformation data

IntroductionIn order to make full use of many kinds of cruStal deformation data to establish dynamic pictUres of crustal strain field, it is necessary to do unified treatment using different types of observation data, and it is not difficult in the respect of models (JIANG, et al, 1999). BUt strsin valuescomputed from different kinds of dare have obvious difference of orders of magnitude, for example, the strain value of small figure compUtation of mobile observation is generally 10', bUt …     

2005-2008年北京地区典型重力变化跟踪与分析

自2006年起,北京地区一些流动重力测点测值在趋势变化的基础上加速变化,昌平和顺义等测点附近重力场非均匀性变化增强。以北京昌平重力观测点为中心增加2条重力剖面观测线,并进行3期观测,分析重力场演化特征,采用地下水重力效应经验公式、自由空气改正关系式,分别改正地下水位、地壳形变对重力典型变化点的影响。研究表明：重力变化是地下水位、地壳形变影响的结果,重力剖面观测区及附近重力变化比较平稳,变化均在误差范围内,排除该异常是地震前兆异常的可能。     

形变数字化资料对邢台地区地震前兆反应的研究

使用张家口、怀来、赤城、宽城、易县和涉县6个台站共计43个测项的数字化资料,针对2002~2005年邢台地区发生的3个M>4级的中强地震,进行了地震前兆和同震反应研究。发现我省数字化形变资料对3次邢台4级以上地震的形变前兆反应主要是以应变为主,包括体应变和线应变,并且异常形态以固体潮畸变和抖动为主。同震反应比较明显,主要以同震阶跃为主。     

鲜水河断裂形变场、重力场、磁场动态演化特征与地震

据鲜水河断裂跨断层形变测量、流动重力测量和流动磁力测量资料,求取各点的形变速度、重力变化速率及每年各点的总磁场强度,绘出每期 形变、重力、磁力的二维图像。引入分形理论的数盒子方法,计算每幅图的容量维。研究结果表明：鲜水河断裂形变场的二维图像在地震前后的演变与岩石破坏实验过程输出的图像相似,均经历了“复杂－简单－复杂”的演化过程。相应的分维值也同样呈“高值－低值－高值”变化,且地震发生在分维值达最低后恢复过程中。重力场的二维图像在地震前后的变化特征为“简单－复杂”,分维值呈低值向高值变化。磁场的图像变化则呈“复杂－简单”,分维值变化呈降维特征。     

Dynamic pattern characteristics of fault deformation and gravity field in the development process of Yongdeng M S=5.8 earthquake

In this paper, the fault deformation abnormality, dynamic evolution features of gravity and vertical deformation field in the seismogenic process of the Yongdeng, Gansu Province earthquake on July 22, 1995 are studied primarily. There appeared α-β-γ tri-stage anomaly at three sites near the epicenter, and there appeared anomalies of step and sudden jump at more than 10 sites in outer region since 1993. The high value area before shock, coseismic effect and process of recovery aftershock were monitored by portable gravity data. Data reflects the changing process of fault movement from the quasi-linear to the nonlinear in the near source region during seismogenic development of the Yongdeng earthquake and evolution of gravity field from heterogeneity of seismogenic term to quasi-homogeneity of postseismic term. There exists close relationship between strong earthquake and dynamic evolution of regional stress-strain field. Considering all above, the experience and lessons in this medium-short term prediction test are summarized.