关于地震烈度衰减模型的系统偏差

本文讨论在地震危险性分析中目前使用广泛的地震烈度衰减模型,即Cornell建立的点源模型和洪华生(A.H-S.Ang)等建立的断层-破裂模型。与实际烈度资料的比较表明,在等震线狭长的区域,点源模型有系统偏差,通常这种偏差不算严重。为了克服上述偏差,断层-破裂模型引进了破裂长度的概念,但其衰减与实际资料出入较大。与实际地震等震线的比较和计算表明,对大地震沿断层或等震线长轴方向,断层破裂模型总是高估高烈度区而低估低烈度区。此外,本文分析了断层破裂模型产生系统偏差的原因,讨论了点椭圆模型的合理性,并用地震危险性分析实例做了说明。      

测震定位中模型影响的数值实验

本文介绍了定位模型偏差对震源测定的影响的数值实验,结果表明:定位模型的偏差主要影响对浅源地震的深度的测定,对地壳下部地震深度的测定一般影响不大;如果定位模型比实际地壳结构简单,所测定的震源深度往往比实际深度偏大,反之定位的深度一般都偏浅;地壳总厚度的偏差使定位深度产生系统差,偏差和系统差基本一致;同一模型测定的深度值之间具有相对准确的定性意义,可以互相比较,不同模型测定的深度结果一般无此关系。文章最后对实验结果作了简要讨论。     

震后重建项目中基于灰色模型构建的多因素造价控制模型

在当前震后重建项目的多因素造价控制过程中,未考虑造价影响因素造成的偏差,导致控制精度较低,因此需对震后重建项目中基于灰色模型构建的多因素造价控制模型进行研究。从重建项目的造价影响因素入手,分析由于震后重建项目管理程序缺位造成的进度偏差,因为设计能力影响造成的质量偏差以及因建筑材料市场供求状况不稳定造成的价格偏差,计算各影响因素造成的偏差系数,求解得出更为精确的重建项目整体偏差结果。结合灰色模型构建造价控制约束函数,并进行求解,进而完成震后重建项目中多因素造价控制模型的构建。实验结果表明,所构建模型的精确度较高,且与实际值偏离程度小,可信度较高。可以对重建项目进行全方位的动态管理,降低工程成本。     

基于局部一维模型与走时标定的区域三维速度模型构建技术研究

构建区域介质三维速度模型并以之获得准确的区域震相走时,是提高区域地震定位精度的重要手段之一.为充分利用已有的一维模型、GT事件、地质资料等实现三维模型构建,尝试基于目标区域内已有的部分局部一维模型,通过克里金空间插值建立初始三维模型,然后利用GT事件走时数据并参考其它地震地质资料对其不断进行修正,使得其走时偏差图与GT事件走时偏差图一致,进而获得能够提高区域地震定位精度的三维模型.使用不同模型进行的地震定位实验表明,以此方法建立的三维模型的定位偏差较初始模型减少约20％,较好地起到了减小区域震相走时残差,提高区域地震定位精度的作用.     

GOCE卫星SGG数据系统误差的综合标定方法

介绍了GOCE卫星重力梯度数据系统误差的常用求定方法,提出了一种联合卫星轨迹交叉点不符值和现有重力场模型的系统误差综合标定方法.给出了分步解算和整体平差两种解算方法及相应的计算步骤.分步解算是先利用卫星轨迹交叉点不符值确定含尺度影响的偏差漂移项,然后对观测值进行偏差漂移改正,并利用现有重力场模型计算尺度和偏差,最后对偏...     

基于局部一维模型与走时标定的区域 三维速度模型构建技术研究

构建区域介质三维速度模型并以之获得准确的区域震相走时, 是提高区域地震定位精度的重要手段之一. 为充分利用已有的一维模型、 GT事件、 地质资料等实现三维模型构建, 尝试基于目标区域内已有的部分局部一维模型, 通过克里金空间插值建立初始三维模型, 然后利用GT事件走时数据并参考其它地震地质资料对其不断进行修正, 使得其走时偏差图与GT事件走时偏差图一致, 进而获得能够提高区域地震定位精度的三维模型. 使用不同模型进行的地震定位实验表明, 以此方法建立的三维模型的定位偏差较初始模型减少约20%, 较好地起到了减小区域震相走时残差, 提高区域地震定位精度的作用.      

利用高精度GNSS水准及垂线偏差数据分析重力场模型的误差特性

高精度的GNSS水准及垂线偏差等数据对全面评定重力场模型精度具有重要意义.本文利用美国GSVS2011、GSVS2014项目高精度的GNSS水准及垂线偏差等数据,通过谱组合方法分析了DIR-R5、GOCO05S和TIM-R5等具有代表性的重力场模型的可靠阶次,并分别与EIGEN-6C4形成组合模型DIR-R5-Com、GOCO05S-Com、TIM-R5-Com,在此基础上,进而分析了EGM2008、EIGEN-6C4与3个组合模型的误差特性.实验结果表明:(1)DIR-R5、GOCO05S和TIM-R5模型截断至220阶以前是可靠的;(2)整体上,重力场模型沿经圈走向(GSVS2011)的高程异常和垂线偏差精度要优于沿纬圈走向(GSVS2014)的精度;(3)重力场模型垂线偏差卯酉圈分量的精度要优于子午圈分量的精度;(4)模型高程异常在经圈上的相对精度整体上要优于在纬圈上的精度.     

不同R-μ-T关系对比研究及其在高层混合结构位移需求估计中的应用

本文结合弹塑性反应谱的研究,给出了求解钢框架一钢筋混凝土核心筒混合结构位移需求的基本步骤,并采用不同的R-μ—T关系计算了某15层混合结构的位移需求。结果表明：选取不同模型计算所得的位移需求有一定的偏差,偏差大致在25％以内,其中Newmark＆Hall模型会较大幅高估结构的位移需求。通过比较,本文最终选取吕西林、周定松模型,其估计的位移需求与弹塑性时程分析结果的偏差基本控制在30％以内,可以为工程界接受。对比分析不仅表明了选取该模型的合理性,同时说明弹塑性反应谱法是一种比较有效的估计此类结构位移需求的方法,在混合结构基于性态的抗震设计中具有应用价值。     

有色噪声模型下云南地区GPS基准站速度与周期估计

基于2010~2014年云南地区25个GPS连续观测站的三维站坐标时间序列结果,通过不同噪声模型对其进行分析,结果表明:各坐标分量具有不同的噪声特性且最优噪声模型存在多样性,闪烁噪声+白噪声和幂律噪声+白噪声为该区主要的噪声模型,垂向分量最优噪声模型的分布表现出以NW向红河断裂带为分界的地域性。噪声模型与测站运动参数的定量分析表明,噪声模型对测站速度不确定度和年周期振幅不确定度影响较大,有色噪声模型下的速度不确定度和年周期振幅不确定度分别是白噪声模型下的3~7倍和2~3倍;噪声模型对速度及年周期振幅产生少量影响,有色噪声模型和白噪声模型下的线性速度估值偏差一般小于1 mm/a,少数测站垂向分量差异超过1 mm/a,年周期振幅估值偏差一般小于0.5 mm/a,且垂向分量偏差大于水平分量,东向分量偏差大于北向分量。     

活断层带的特征滑动行为与中强以上地震序列

地震序列模型确定了断层带内中强以上地震的时间、强度和位置三方面的非随机性,从而导致了地震序列的特定性。本文按地震序列模型重演了鲜水河断裂带过去约一百年的地震序列,各次地震的时间偏差不超过其重复周期的10％。震级偏差不超过0.3,破裂位置也基本吻合。在此基础上,对该断裂带未来150年的中强以上地震序列进行了预测。     

Long-Term Changes in the Number and Magnitude of Forbush-Effects

The IZMIRAN database of Forbush effects and interplanetary disturbances has been used to study long-term changes in the number and magnitude of Forbush effects in the last six solar cycles (1957–2016) for cosmic rays of rigidity of 10 GV. Solar activity cycles have been shown to be well expressed in data of Forbush effects, especially in large magnitude events that almost disappear in minima. The changes in the distribution of Forbush effects and the decrease in their average values from solar activity maximum to minimum are explained by the predominance of cosmic-ray variations due to the action of coronal holes at low activity. It should be noted that the current cycle involves fewer and generally weaker Forbush effects than in the previous five cycles. For each month, an FD index combining the magnitude and number of Forbush effects and convenient for studying long-term variations has been proposed and calculated.     

Main Properties of Forbush Effects Related to High-Speed Streams from Coronal Holes

The IZMIRAN database of Forbush effects and interplanetary disturbances was used to study features of the action of high-speed solar wind streams from coronal holes on cosmic rays. Three hundred and fifty Forbush effects created by coronal holes without other actions were distinguished. The mean values and distributions have been found for different characteristics of events from this group and compared with all Forbush effects and Forbush effects caused by coronal ejections. Despite the great differences in high-speed streams from coronal holes, this group turned out to be more compact and uniform as compared to events related to coronal ejections. Regression dependences and correlation relations between different parameters of events for the studied groups have been obtained. It has been shown that Forbush effects caused by coronal ejections depend considerably more strongly on the characteristics of interplanetary disturbances as compared to Forbush effects related to coronal holes. This suggests a significant difference between the modulation mechanisms of Forbush effects of different types and corroborates earlier conclusions based on indirect data.     

Earthquake Damage Scenarios of the Building Stock of Potenza (Southern Italy) Including Site Effects

Damage scenarios relevant to the building stock of the town of Potenza, Southern Italy, are presented. A procedure for the preparation of scenarios has been purposely set up. In the first step, the inventory of the building stock has been made. Location and characteristics of buildings have been obtained from a survey carried out after the 1990 Potenza earthquake and further updated in 1999. In the second step, the absolute vulnerability of the buildings has been evaluated. A hybrid technique has been used, where typological analyses and expert judgement are combined together. Beyond the classes of vulnerability A, B and C of the MSK scale, the class D of EMS98 scale, for the less vulnerable buildings, has been considered. The third step has been the selection of the reference earthquakes by including also local amplification effects. Two events with 50 and 475 years return periods have been chosen as representative, respectively, of a damaging and of a destructive seismic event expected in Potenza. The sites that may exhibit important amplification effects have been identified using the first level method of the TC4 Manual. Damage scenarios of dwelling buildings have been prepared in the fourth step and reported in a GIS. They are relevant to the selected reference earthquakes, taking into account or not site effects. The generally low vulnerability of buildings results in a limited number of damaged buildings for the lower intensity earthquake, and of collapsed buildings, for the higher intensity earthquake. The influence of site effects on the damage distribution is significant. This revised version was published online in July 2006 with corrections to the Cover Date.     

像力及其在震源过程中的作用

本文应用固体物理学中位错所受自由面的像力的概念来讨论调整单元(自由面或软弱介质)对孕震震源地区断层的蠕裂、临震前锁住段断层中预位移的传播以及地震发生时裂缝的失稳传播的影响。推导了几种不同形状的自由边界对螺型位错和刃型位错作用的像力的表达式。以直立倾滑断层为例求出了震源地方断层某一段发生相对位移时由于自由面的像力作用而在断层上引起的附加应力场。估算了实际断裂情况下此附加应力场的数量级。认为像力的作用在震源过程中尤其是在研究对大震的触发作用时是不可忽视的。从像力的观点出发解释了地震发生时的一些现象。     

用广义反演方法估算首都圈地区台站场地效应

本文利用2001—2006年首都圈地区的SH波数字化地震资料, 用广义逆矩阵联合反演的方法得到了63个台站的场地效应值。 基岩场地的场地效应比较稳定, 在1～10 Hz范围内为1左右; 沉积场地在低频场地效应较高, 在1～8 Hz范围内在3～7之间, 5 Hz左右场地效应有明显的突起, 以后随频率增加降低。 结果表明, 台站岩性是影响场地效应形态和大小的主要因素, 此外其场地效应还可能与所处的局部地质构造等因素有关。     

Simultaneous infrasonic,seismic, magnetic and ionospheric observations in an earthquake epicentre

Various pre-seismic and co-seismic effects have been reported in the literature in the solid Earth, hydrosphere, atmosphere, electric/magnetic field and in the ionosphere. Some of the effects observed above the surface, particularly some of the pre-seismic effects, are still a matter of debate. Here we analyze the co-seismic effects of a relatively weak earthquake of 28 October 2008, which was a part of an earthquake swarm in the westernmost region of the Czech Republic. Special attention is paid to unique measurements of infrasonic phenomena. As far as we know, these have been the first infrasonic measurements during earthquake in the epicentre zone. Infrasonic oscillations (～1–12 Hz) in the epicentre region appear to be excited essentially by the vertical seismic oscillations. The observed oscillations are real epicentral infrasound not caused by seismic shaking of the instruments or by meteorological phenomena. Seismo-infrasonic oscillations observed 155 km apart from the epicentre were excited in situ by seismic waves. No earthquake-related infrasonic effects have been observed in the ionosphere. Necessity to make vibration tests of instruments is pointed out in order to be sure that observed effects are not effects of mechanical shaking of the instrument.     

新疆平原沙漠区湖泊干缩生态效应初探

50年代至80年代初,新疆平原沙漠区湖泊普遍处于退缩状态,一些湖泊干涸或基本干涸,这是湖泊所在流域上、中游地区灌溉事业发展的必然结果。到目前为止,湖泊干缩所引起生态环境的变化,其范围主要限于湖周有限区域;变化的幅度尚未达到对人类生活和生湖泊及湖周有限区域生态环境的恶化中,人类不正确的活动方式占了很大比重。     

鄂尔多斯盆地北部黄土沙漠区隐蔽薄气层预测

长庆油田公司针对黄土沙漠区低孔、低渗、薄气藏的地震目标处理,经过多年的探索与实践,已形成了一套适合该类气藏特点的储层横向预测技术。在榆林、乌审旗、苏里格庙和神木等地区的上古生界天然气勘探、开发阶段取得了显著效果,使长庆油田上古生界天然气储量连续八年保持稳定增长。本文详细剖析了该技术的应用效果及经验。     

Research on the random seismic response analysis for multi- and large-span structures to multi-support excitations

The pseudo excitation method(PEM) has been improved into a more practical form,on which the analytic formulae of seismic response power spectral density(PSD) of simplified large-span structural models have been derived.The analytic formulae and numerical computing results of seismic response PSD have been derived to study the mechanism of multi-support excitation effects,such as the wave-passage effect and incoherence effect,for the seismic response of multiand large-span structures.By using a multi-span truss as an example,the influence of multi-support excitation effects on the seismic response of such structures is studied.     

地下铁道的振动及其控制措施的研究

150年来地下铁道得到了广泛的发展,近20年来我国的地下铁道更是得到了迅猛的发展.在地下铁道给城市居民的工作和生活带来方便的同时,其引发的振动与噪音也给城市建设和居民生活带来了危害.本文从振动产生、振动传播和振动作用三个阶段论述了地铁振源及其传播的规律;传播特性与振源频率、振源与轨道距离、振动频率,以及列车运行速度、隧道埋深、地质条件、建筑物结构等有关;振动传播影响因素包括:土壤类型、钢轨类型、轨道类型、建筑物质量类型、建筑物材料等;地铁振动的危害是多方面的,噪声干扰人们的日常生活,振动对建筑物的安全性、使用寿命造成影响,同时还影响精密仪表测量等.本文提出了在规划设计阶段、施工阶段的振动控制措施,以期减小其危害.