四川地区地震动峰值衰减规律研究

基于四川省地震监测台网27个基岩台站,2008年5月12日——2008年6月10日105次地震（震级ML=4.0——6.4,震中距△=26——623km）的8505条宽频带速度记录,利用实时仿真方法得到了相应的加速度记录,进而对数据进行回归分析,获得了四川地区基岩场地中小地震峰值加速度和峰值速度的衰减关系,并用最近发生的一次4.8级地震对该规律进行了验证．通过四川台网的记录,提出了符合四川地质条件的衰减关系      

Ground motion attenuation relation for small to moderate earthquakes in Fujian region, China

We collect 1974 broad-band velocity records of 94 earthquakes (ML=2.8~4.9, △=13~462 km) from seven stations of the Fujian Seismic Network from March 1999 to March 2007. Using real-time simulation, we obtain the corresponding acceleration and then adopt different models to analyze the seismic data. As a result, a new attenuation relationship between PGA and PGV of the small and moderate earthquakes on bedrock site in Fujian region is established. The Yongchun earthquake occurred recently verifies the attenuation relationship well. This paper provides a new approach for studying the ground motion attenuation relationship using velocity records.     

福建地区中小地震地震动峰值衰减规律研究

基于福建省地震监测台网7个基岩台站1999——2007年获得的94次地震(ML=2.8——4.9,Delta;=13——462 km)的1974条宽频带速度记录, 利用实时仿真方法得到了相应的加速度记录, 进而利用不同的模型对数据进行回归分析, 获得了福建地区基岩场地中小地震峰值加速度和峰值速度的衰减关系, 并用2007年8月29日永春M4.6地震对该规律进行验证. 本文方法为速度资料研究地震动衰减规律提供了新的思路.      

福建地区中小地震加速度反应谱衰减规律

本文基于收集福建省地震监测台网7个基岩台站从1999年至2007年获得的94个地震(ML=2.8～4.9,△=13～462 km) 的1974条宽频带速度记录,利用实时仿真方法得到了相应的加速度记录,进而得到了福建地区基岩场地中小地震绝对加速度反应谱的衰减关系.对基岩反应谱有影响的因素主要有震源、传播途径,本文简要分析这两个因素对地震动的影响.此项工作对于福建省抗震设防具有重要的意义.     

中小震近场地震动估计中地震动衰减关系的适用性分析

核工程场地设计基准地震动确定中涉及弥散地震的地震动估计，这导致中小震近场地震动估计成为被关注的研究课题。本文基于一些中小震近场地震动记录资料，分析和探讨了国内外多种地震动衰减关系对中小震近场地震动估计的适用性问题，并结合我国几个核工程地震问题研究工作的实践对中小震近场地震动衰减关系确定的思路和原则提出了建议。     

陕西地区地震动衰减关系研究

通过分析陕西省丰富的地震活动资料,包括鲜明的地震活动与震害分布的地域性特点以及地震地质环境特点,将陕西省分为三个分区,来进行地震动衰减关系的研究.研究内容主要包括地震烈度衰减关系和基岩地震动衰减关系.选择美国西部作为参考区,三个分区分别作为研究区,采用可逆法进行映射转换计算,得到了三个分区的基岩地震动衰减关系,在转换过...     

Attenuation modeling of recent earthquakes in Turkey

This paper deals with the derivation of a consistent set of empiricalattenuation relationships for predicting free-field horizontal components ofpeak ground acceleration (PGA) and 5 percent damped pseudoacceleration response spectra (PSA) from 47 strong ground motion recordsrecorded in Turkey. The relationships for Turkey were derived in similarform to those previously developed by Boore et al. (1997) for shallowearthquakes in western North America. The used database was compiledfor earthquakes in Turkey with moment magnitudes (M_w) = 5 thatoccurred between 1976–1999, and consisted of horizontal peak groundacceleration and 5 percent damped response spectra of accelerogramsrecorded on three different site conditions classified as rock, soil and softsoil. The empirical equations for predicting strong ground motion weretypically fit to the strong motion data set by applying nonlinear regressionanalysis according to both random horizontal components and maximumhorizontal components. Comparisons of the results show that groundmotion relations for earthquakes in one region cannot be simply modifiedfor use in engineering analyses in another region. Our results, patternedafter the Boore et al. expressions and dominated by the Kocaeli andDüzce events in 1999, appear to underestimate predictions based ontheir curves for up to about 15 km. For larger distances the reverse holds.     

Ground motion prediction equations based on shallow crustal earthquakes in Georgia and the surrounding Caucasus

Strong ground motions caused by earthquakes with magnitudes ranging from 3.5 to 6.9 and hypocentral distances of up to 300 km were recorded by local broadband stations and three-component accelerograms within Georgia’s enhanced digital seismic network. Such data mixing is particularly effective in areas where strong ground motion data are lacking. The data were used to produce models based on ground-motion prediction equations (GMPEs), one benefit of which is that they take into consideration information from waveforms across a wide range of frequencies. In this study, models were developed to predict ground motions for peak ground acceleration and 5%-damped pseudo-absolute-acceleration spectra for periods between 0.01 and 10 s. Short-period ground motions decayed faster than long-period motions, though decay was still in the order of approximately 1/r. Faulting mechanisms and local soil conditions greatly influence GMPEs. The spectral acceleration (SA) of thrust faults was higher than that for either strike-slip or normal faults but the influence of strike-slip faulting on SA was slightly greater than that for normal faults. Soft soils also caused significantly more amplification than rocky sites.     

近断层地震动加速度峰值衰减规律的研究

提出了近断层地面运动的衰减模型,对全球范围内6．0≤Mw≤7．6且震源深度均小于20km的636条地震动加速度峰值进行了统计分析,确定了本文研究的近断层区域为断层距25km,利用此范围内的440条记录进行了近断层加速度衰减规律的研究。水平地震记录分为硬土和软土两种场地类型,竖向地震记录只考虑土层场地,利用最小二乘法进行数据拟合分析,得到PGA随断层距和震源深度变化在不同震级处形成的衰减曲面,分析了近断层处水平、竖向的PGA以及竖向与水平PGA之比(V／H)的衰减规律。     

Seismic motion attenuation relations in Si-chuan and adjacent areas

The Sichuan and adjacent areas is divided into southwest China region (SWCR) and Sichuan Basin region (SCBR) according to tectonic backgrounds and seismic damage distribution features. 96 modern destructive earthquakes in SWCR and 40 in SCBR are gathered respectively. All their magnitude parameters are checked. Based on the statis-tic relations between epicentral intensity and magnitude as well as relation between sensible radius and magnitude, the near and far field seismic intensity attenuation features are represented and controlled. And then the seismic intensity attenuation relations along major axis, minor axis and mean axis are established separately. The system-atic deviations of surface wave magnitude between China seismograph network and U.S. seismograph network are considered in this paper. By making use of the new attenuation relations of bedrock horizontal ground acceleration response spectrum in west U.S., the attenuation relations of bedrock horizontal ground acceleration response spec-trum in SWCR and SCBR are digital transformed based on the attenuation model considering acceleration satura-tion of distance and magnitude in near field.     

川滇地区水平向强地震动衰减关系研究

利用近几年在川滇地区破坏性地震及汶川地震强余震中获得的951条加速度记录, 通过选取合适的衰减关系形式和距离参数, 经统计获得了川滇地区水平向峰值加速度与35个周期点对应的加速度反应谱(阻尼比0.05)衰减关系. 统计结果显示, 震级越大, 地震动随距离的衰减越慢; 加速度反应谱的短周期部分随距离的衰减明显快于长周期部分; 中强地震在近场也会产生较大的峰值加速度和较高的短周期加速度反应谱. 由于统计资料的非完整性, 本文统计结果尚不宜直接应用于相关工程场地的设计地震动参数确定中. 但本文结果与目前由转换方法得到的我国西部地震动参数衰减规律的较大差异提示： 进一步深入研究我国地震动参数衰减规律应是紧迫而重要的任务.     

近断层地震动速度、位移峰值衰减规律的研究

在全球范围内选取6．0≤Mw≤7．6、震源深度H≤20km且断层距df≤40km的地震动速度和位移峰值数据．进行分组统计分析,确定了PGV和PGD的近断层研究区域分别为20km和15km。认为两水平分量为2条独立数据,在各自研究区域分别得到由366条PGV和265条PGD数据组成的数据库;其中水平方向分为硬土和软土2类场地,竖向只考虑土层场地．利用作者前文已提出的近断层地震动衰减模型和最小二乘法进行数据拟合分析．得到PGV和PGD随断层距和震源深度变化的衰减曲面,分析了水平、竖向以及竖向与水平比值的衰减规律。     

Generating ground motion by two new techniques of adding harmonic wave in the time domain and approximating to response spectrum as a whole

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地震动衰减关系拟合的新两步法

本文根据地震动衰减的理论分析结果和强震观测记录，提出了一种新的拟合地震动衰减关系的两步法，并用新近补充，完善的美国西部强震记录，对PGA，EPA和EPV衰减特性进行了分析，结果表明，建议的方法能反映近场强震地震动饱和效应和大震远场衰减的特点。     

云南地区中小地震静力学和动力学参数定标关系

通过消除S波观测谱中的传播路径、场地响应、仪器响应等影响因素,得到中小地震的震源谱.根据Brune震源模型,运用遗传算法计算了地震矩、应力降、震源半径等震源参数;通过考虑由于有限的仪器带宽带来的地震辐射能量低估及补偿问题,测定了中小地震辐射能量;分析了云南地区ML2.0 ～5.3地震静力学和动力学参数定标关系.结果表明:地震矩为2.1×1012～1.2 ×1016N·m,地震矩M0和震级ML的线性关系式为lgM0=1.01ML+10.59;震源破裂半径在86.9～1220.4m之间,地震矩M0与震源半径a之间的关系式为lgM0 =0.003a+ 12.90;应力降结果介于0.03 ～57.55MPa之间,当M0＜4×1014N.m时,应力降随地震矩的增大而增大,当M0≥4 ×1014N·m时,应力降与地震矩之间无明显的依赖关系;地震矩M0与拐角频率∫c明显有依赖关系,二者之间的关系式为lgfc=- lgM0+5.32;地震辐射能量ER在3.01×106～2.06×1012J之间,地震辐射能量ER与震级ML之间的关系为lgER=1.18ML+5.69.当M0＜4×1014N·m时,折合能量有随地震矩增大而增大的趋势,当M0≥4×1014N·m时,折合能量不随地震矩的增大而变化;地震视应力范围为0.02～31.4MPa之间,视应力与震源深度之间没有明显的依赖性.     

不同地震动衰减关系模型在河北地区应用

河北省目前主要采用的是霍俊荣给出的适用于中国华北地区的地震动反应谱的衰减,该衰减关系分为Ⅱ型衰减关系模型和Ⅲ型衰减关系模型。使用Ⅱ型、Ⅲ型模型以及烈度衰减关系,对石家庄、邯郸、邢台、保定、张家口、承德、唐山、秦皇岛、廊坊、沧州10个地级市以及沙城、三河、宁晋、磁县等曾经历史上发生过大地震的地方,进行50年超越概率10%的峰值加速度和烈度值的计算,得出不同衰减关系模型适合使用于不同地区。     

Development of attenuation relation for the near fault ground motion from the characteristic earthquake

A composite source model has been used to simulate a broadband strong ground motion with an associated fault rupture process. A scenario earthquake fault model has been used to generate 1 000 earthquake events with a magni-tude of Mw8.0. The simulated results show that, for the characteristic event with a strike-slip faulting, the character istics of near fault ground motion is strongly dependent on the rupture directivity. If the distance between the sites and fault was given, the ground motion in the forward direction (Site A) is much larger than that in the backward direction (Site C) and that close to the fault (Site B). The SH waves radiated from the fault, which corresponds to the fault-normal component plays a key role in the ground motion amplification. Corresponding to the sites A, B, and C, the statistical analysis shows that the ratio of their aPG is 2.15:1.5:1 and their standard deviations are about 0.12, 0.11, and 0.13, respectively. If these results are applied in the current probabilistic seismic hazard analysis (PSHA), then, for the lower annual frequency of exceedance of peak ground acceleration, the predicted aPG from the hazard curve could reduce by 30% or more compared with the current PSHA model used in the developing of seismic hazard map in the USA. Therefore, with a consideration of near fault ground motion caused by the rupture directivity, the regression model used in the development of the regional attenuation relation should be modified accordingly.     

地震反应分析中输入界面的选取对地表地震动参数的影响

地震反应分析中输入界面选取合理与否对设计地震动参数有重要影响。基于唐山地区钻孔剖面,分别选取剪切波速为500m/s的硬黏土和800m/s的岩石顶面作为基岩输入界面,采用一维等效线性化方法讨论中硬场地输入界面的选取对地表地震动参数的影响,结果表明:(1)地表峰值加速度放大倍数及地表加速度反应谱特征周期都随输入界面深度的增加而递增,且这种递增与输入地震动的强度及频谱特性都有密切联系;(2)随着输入界面深度的增加,地表加速度反应谱几乎全频段内增大,仅在短周期内出现减小的情况,但幅度十分有限;(3)中硬场地地震反应分析中基岩输入界面宜取剪切波速为800m/s的土层顶面。     

Ground motion attenuation of M_s8.0 Wenchuan earthquake

The great MS8.0 Wenchuan earthquake has been the most destructive earthquake since 1949 in China. The earthquake occurred no more than half a year after the establishment of the National Strong Motion Observation Network System (NSMONS) of China; what is more, the epicenter was located in the area with dense strong motion observation stations so that a large number of strong motion records of the main shock were obtained. In this paper, 501 strong motion records from 167 observation stations are utilized to...     

中强地震活动区地震动衰减关系的确定

地震动衰减关系是影响地震安全性评价特别是地震区划结果的重要因素.我国现行的地震动衰减关系主要是依据6级以上地震的地面运动资料得到的,并没有考虑中强地震的衰减特性.为此,文中利用现有的烈度资料和其他可供参考的研究成果来建立我国中强地震活动区的地震动衰减关系.收集了我国华中、华南、东北等地区的51次地震的烈度等震线资料,运用单随机变量加权最小二乘回归法得到中强地震活动区烈度衰减关系.然后以美国西部地区为参考地区,运用缺乏地震动参数的地震动估计方法-地震对映射法得到中强地震活动区峰值加速度和有效峰值加速度衰减关系.最后,通过与我国强地震区和中强地震区已有的烈度衰减关系和地震动衰减关系的对比,验证了得出的我国中强地震活动区烈度衰减关系和地震动衰减关系的合理性.