关于在地震预报中遇到的几个问题的探讨

地震台站工作人员 ,在进行观测资料分析、地震预报研究过程中 ,往往会遇到的几个问题 :1、手段单一 ,对于前兆现象无法全面表述。 2、如何识别异常与地震之间的关系。 3、如何兼顾点和面的关系。     

桩基沉降量的灰色预测

利用实测的桩基静载试验数据 ,用灰色系统理论建立桩基沉降量的灰色GM(1,1)预测模型 ,可以模拟桩基静载试验P s曲线的未知部分。研究结果表明 ,建立的GM(1,1)模型可有效预测桩基沉降量 ,对进一步分析桩基的承载性能有理论与实际意义。     

通渝隧道围岩变形的神经网络预测

隧道新奥法施工中 ,常以围岩变形量作为评判围岩稳定性和支护结构经济合理性的重要指标。公路隧道围岩变形量是随时间而变化的数据序列 ,因而可以建立一些实时跟踪预测模型和方法。根据通渝隧道围岩拱顶下沉位移变形的特性 ,采用神经网络技术来预测其变形量 ,结果表明该方法简易、有效     

Design Earthquakes in the U.K.

Three sites in the UK are taken, representative of low, medium and high hazard levels (by UK standards). For each site, the hazard value at 10⁻⁴ annual probability is computed using a generic seismic source model, and a variety of ground motion parameters: peak ground acceleration (PGA), spectral acceleration at 10 Hz and 1 Hz, and intensity. Disaggregation is used to determine the nature of the earthquakes most likely to generate these hazard values. It is found (as might be expected) that the populations are quite different according to which ground motion parameter is used. When PGA is used, the result is a rather flat magnitude distribution with a tendency to low magnitude events (\le 4.5 ML) which are probably not really hazardous. Hazard-consistent scenario earthquakes computed using intensity are found to be in the range 5.8–5.9 ML, which is more in accord with the type of earthquake that one expects to be a worst-case event in the UK. This revised version was published online in July 2006 with corrections to the Cover Date.     

碳酸盐岩储层缝洞发育带预测:以塔河油田为例

塔河油田碳酸盐岩为古岩溶喀斯特化与受后期构造叠置改造的孔、洞、缝等组成的非均质储层,储层具有规模不同、空间形态不规则、充填性质各异的复杂组合特征以此为对象通过分解地震波场不同特征信号,开发了一系列针对不同储层目标的叠前叠后地震预测技术,不同特征地震预测结果经综合叠置验证分析,实现了残丘体上叠置的孔、洞、缝及古地貌的精细刻画及表征,展示了缝洞空间纵横交错的叠置关系,提高了复杂储层空间展布规律的认识及精确定位。     

A coherency function model of ground motion at base rock corresponding to strike-slip fault

IntroductionEarthquakedamagesurveyandresearchresultshavedemonstratedthatspatialdistributiondifferenceofgroundmotionisoneoftheimportantreasonswhichcausedlongstructure(eglongspanbridge,undergroundpipe)destroy.Thathowtoprovideareasonableinputofgroundmotionfieldforaseismicdesignoflongstructureisaurgentprobleminearthquakeengineeringfield.Atpresent,themethodtostudyspatialvariationofgroundmotionsisadoptingstatisticanalysisbasedondensearrayrecordssuchasSMART-1array,etc,togetcoherencyfunctionofground…     

Investigation of upper crust anisotropy in Ghaen-Birjand region, east-central Iran

IntroductionWhenpropagatingthroughananisotropicmedium,ashearwavesplitsintotwo(quasi)shearwaveswithdifferentpropagationspeedsandpolarizedorthogonally.Owingtotherecentdevel-opmentofseismicobservationsystem,detectionofshearwavessplittingwithverysmalldelaytimesbetweenfasterandslowershearwavesbecameavailableandprovidedpowerfulapproachfordetectionofcrustalanisotropy.Crampin(1978)emphasizedtheroleofalignedmicrocracksasacauseofcrustalanisotropyandpointedoutthatforverticallyalignedmicrocracksthedirecti…     

Fundamental study on the response characteristics of drivers during an earthquake based on driving simulator experiments

After the 1995 Kobe earthquake, the expressway structures in Japan were retrofitted and they will not now be seriously damaged under a certain level of strong earthquake motion. However, the stability of a moving vehicle has not been investigated yet. It has been reported that drivers feel seismically induced vibrations, especially in the transverse direction of vehicles. Owing to this phenomenon, drivers have some difficulty in controlling the vehicles during strong shaking. For further safety promotion of the expressway networks, it is important to understand the drivers' reactions to seismic motion. The present authors have performed a series of seismic response analyses of a moving vehicle to investigate its response characteristics based on numerical simulation. However, the responses of the driver were not considered in the simulation process. In order to investigate the drivers' reactions during an earthquake, a series of virtual tests were conducted using a driving simulator. This driving simulator has six servomotor‐powered electric actuators that control its motions. Several types of tests were carried out for different examinees to investigate drivers' responses while controlling the simulator under seismic motion. The results of this study showed that a larger response time lag to strong shaking and over turning of the steering wheel may shift the vehicle into the next lane. According to this finding, trafficaccidents could possibly occur under strong ground shaking in the case of heavy traffic. Copyright © 2004 John Wiley & Sons, Ltd.     

几种空气质量预报方法的预报效果对比分析

目前应用于我国各个城市空气质量预报业务的预报方法主要有三种 :数值模式预报、统计预报和综合经验预报。这几种预报方法都有其各自的优势 ,同时也存在一些不足。应用以上方法对天津市市区进行空气质量业务预报 ,通过实测资料与预报结果进行对比分析 ,给出这几种方法在天津市区空气质量预报中的预报效果客观评价。     

An attenuation relationship based on Turkish strong motion data and iso-acceleration map of Turkey

This paper presents an attenuation relationship of peak ground acceleration (PGA) derived from Turkish strong motion data for rock, soil and soft soil sites and an iso-acceleration map of Turkey based on this relationship. For the purpose, among all the three-component accessible records, 221 records from 122 earthquakes that occurred in Turkey between 1976 and November 2003 were selected. The database was compiled for earthquakes with moment magnitudes (M_w) and PGA values ranging between 4.1 and 7.5, and 20 and 806 gal, and distances to epicenter considered in the database were between 5 and 100 km. From the regression analysis of the data, an attenuation equation of PGA considering rock, soil and soft soil conditions was developed. The PGA values predicted from the equation suggested in this study and those both from a few domestic equations and some imported equations were compared. In addition, an iso-acceleration map of Turkey was constructed using the suggested attenuation equation and considering both known active faults and epicenter locations of the earthquakes that have occurred in Turkey.