新疆维吾尔自治区地震局参加1995年度地震观测资料全国评比

新疆维吾尔自治区地震局参加１９９５年度地震观测资料全国评比根据国家地震局震科［１９９６］０２８号＂关于１９９５年度地震观测资料全国统评结果的通知＂，自治区地震局送交３１项参评资料。在综合评比中乌鲁木齐台获电磁和地下流体学科全国第１名、地壳形变学科第２...     

1998年度新疆维吾尔自治区地震局地震观测资料质量检查评比工作结束

１９９８年度新疆维吾尔自治区地震局地震观测资料质量检查、验收、评比工作会议于１９９９年元月６日至１０日在乌鲁木齐召开。来自全疆各地震台站、地方地震局（办）和局有关业务单位的５０名代表,按学科组成９个专业评比组,对全疆３９个单位提交的１０３项观测资料（无线通讯网评比结果未统计在内）,根据观测规范和有关学科评比标准,进行了全面、认真的检查评比。评比结果：优秀为７９台项,良好为１５台项,及格为５台项,不及格为４台项,有７个单位获全优。另有８台项观测资料或因断记时间长或因观测环境长期受干扰,导致资料失去…     

山西地区地震综合概率预测模型及回溯性检验

概率地震危险性分析是对相关区域地震活动水平的估计,是量化地震危险性的有效手段。基于泊松分布模型获得山西地区背景地震概率,结合每个单项方法预测效能获取的指标权重,采用综合概率法得到山西地区基于多种单项预测方法的地震综合概率模型。对 1985年以来山西地区 M_S ≥ 5.0地震进行回溯性检验,结果表明：异常点受控于统一应力场,震前各类（包括测震、形变、电磁以及流体学科）预测指标均存在且表现出准同步性;震级大小与异常数量呈一定正相关性,震级越大,异常指标越多,综合概率值越大。     

地壳形变测量用于地震预报的研究

本文给出一个用形变资料预报大陆地震的基本模式；①用大面积形变资料进行地震背景的，确定地震危险区，并综合各种手段对危险区震情的发展进行监测；②在重点监视区内布设形变监测台网，寻找形变敏感点，利用形变测量手段（如跨断层短水准。短基线测量手段等）捕捉中短期地震前兆信息，进行中短期震情预测，为短临形变监测手段提供依据。③建立固定形变监测台站进行连续形变的观测（如连通管、倾斜仪、伸缩仪、应变仪等），捕捉临震     

形变台站防雷保护及接地改进

通过对典型形变台站遭雷害的调查,指出形变台站受雷害或干扰的途径是：（１）雷击避雷针的雷电过电压和大电流;（２）交流供电线路上的雷直击过电压与感应过电压等。在分析和归纳后针对性地提出并实践了：（１）应用半导体少长针消雷器防直击雷害;（２）建立接地地风和设计过压保护单元电路或雷击期启用ＵＰＳ以防电子设备的感应雷害;（３）对架空供电进线换用埋地金属外皮屏蔽电缆以防路线来波浸入等综合治疗措施,收到了显著的     

基于方差分量估计的多源InSAR数据自适应融合形变测量

近年来,合成孔径雷达干涉测量（Interferometric Synthetic Aperture Radar,InSAR）技术在地面沉降监测方面展现了巨大的应用潜力,但受其重访周期和一维形变测量能力的限制,仅利用单一轨道卫星观测数据很难揭示真实的地表形变特征及其演化规律.随着在轨运行的SAR卫星系统不断增加,使得融合相同时间段内覆盖同一区域的多源多轨道InSAR数据成为可能.然而目前普遍采用的多源InSAR数据融合方法均为针对大尺度形变监测设计,或者忽略南北向形变甚至水平形变,容易造成误判.为此,本文对经典小基线集（Small Baseline Subset,SBAS）时序InSAR分析方法进行改进,在其形变反演模型中加入东西向和南北向形变参数,采用方差分量估计方法解算多源观测数据验后方差,通过迭代精化确定权重矩阵,从而获得形变参数的最优估值.使用美国南加州地区的ALOS PALSAR和ENVISAT ASAR数据开展实验,利用南加州综合GPS网（SCIGN）位于研究区域内的9个站点观测数据进行验证,结果表明本文方法得到的融合形变测量结果在垂直向上能够准确反映地表形变波动,周期性与GPS观测比较一致;同时,融合得到的三维形变场显示南加州洛杉矶地区存在不可忽略的水平形变,东西向形变测量精度略高于南北向.因此,基于方差分量估计的多源InSAR融合方法在提高形变测量时间序列连续性的同时,能够更准确地反演研究区域三维形变特征.

     

唐山地区跨断层流动形变监测场地优选

针对隐伏断裂的特点,在前人研究成果的基础上,充分利用唐山活动断层探测成果,进行野外调查;依据相关规范,结合环境条件、自然条件,对6个场地进行了综合分析,优选出适宜于跨断层流动形变监测的场地。     

从地质构造探讨地震预测

在地震和地质构造关系上,作者对以下几个问题阐述了自己的看法:（1）地震发生的动力;（2）断层和地震的关系;（3）浅源地震和深源地震;（4）稳定区与活动区;（5）平静期与活动期;（6）垂直地形变与水平地形变.作者认为地壳的水平移动可能是发震的主要动力,因此认为在常发震区经常进行大地测量,观察各地的水平地形变,对中、长期地震预报可能起到有效的作用.     

从地质构造探讨地震预测

在地震和地质构造关系上,作者对以下几个问题阐述了自己的看法:（1）地震发生的动力;（2）断层和地震的关系;（3）浅源地震和深源地震;（4）稳定区与活动区;（5）平静期与活动期;（6）垂直地形变与水平地形变.作者认为地壳的水平移动可能是发震的主要动力,因此认为在常发震区经常进行大地测量,观察各地的水平地形变,对中、长期地震预报可能起到有效的作用.     

泾阳ML5.2级地震的地形变特征

运用褶积、广义回归及差分方法对泾阳地震前后关中地区跨断层形变资料进行了分析研究,结果显示：（１）泾阳地震是大面积应力积累和调整的结果;（２）所监光明日报 各断裂活动丰中短期形变异常;呈现出明显的阶段性活动特征;（３）进入短期的异常标志是中短期的或反向;（４）各断层活动速率呈准同步变化,曲线形态大都呈现典型的α、β、γ相变化。     

Optimum tuned-mass dampers for minimizing steady-state response of support-excited and damped systems

A numerical searching procedure to find the optimum tuning frequency and damping ratio of the tuned-mass damper which can reduce the steady-state response of damped main systems to a minimum level is developed and applied to the two different harmonic excitation sources, support motion of fixed-displacement amplitude and support motion of fixed-acceleration amplitude. The explicit formulae for these optimum parameters are then derived through a sequence of curve-fitting schemes. It has been found that, as the error of the explicit formulae is negligible, they provide a convenient tool to compute the optimum parameters in engineering applications. The numerical results show that the tuned-mass damper is less effective in reducing the system's response when there is a high level of damping incorporated into the system. It is also found that the optimum tuning frequency is strongly influenced by the damping level of a system, especially in regard to the fixed-acceleration support motion, but the optimum damping ratio of the tuned-mass damper is not sensitive to the damping level of a system. The response of the damped system using the undamped optimum value as the damping of the tuned-mass damper is not much different from the response using the damped optimum value.     

Optimum Multiple Tuned Mass Dampers for base-excited undamped system

Optimum parameters of Multiple Tuned Mass Dampers (MTMD) for an undamped system to harmonic base excitation are investigated using a numerical searching technique. The criteria selected for the optimality is the minimization of steady-state displacement response of the main system. The explicit formulae for the optimum parameters of MTMD (i.e. damping ratio, bandwidth and tuning frequency) are then derived using curve-fitting scheme that can readily be used for engineering applications. The error in the proposed explicit expressions is investigated and found to be quite negligible. The optimum parameters of the MTMD system are obtained for different mass ratios and number of dampers. Copyright © 1999 John Wiley & Sons, Ltd.     

An Estimate of Global Mean Sea-level Rise Inferred from Tide-gauge Measurements Using Glacial-isostatic Models Consistent with the Relative Sea-level Record

This study is concerned with the influence of the glacial-isostatic adjustment caused by the last Pleistocene deglaciation on the present-day sea level. The viscoelastic deformation caused by the time-variable ice and ocean loads is simulated by computing the resulting perturbations for a spherical, self-gravitating, incompressible, Maxwell-viscoelastic earth model. The associated variation of the earth rotation is described in terms of the Liouville equation, which is solved by means of the MacCullagh formulae. This allows the determination of the vertical displacement and geoid height and, thus, the solution of the sea-level equation. We test several viscosity and ice models and evaluate them by comparison of the computed response with the Holocene relative sea-level record. Using the optimum combination of viscosity and ice models, we then estimate the influence of the last Pleistocene deglaciation on the tide-gauge measurements. A comparison between the observational and residual linear trends for the tide-gauge measurements shows a significant reduction of the variance and geographical variability for the latter, in particular for the formerly ice-covered regions of North America and Scandinavia. The favoured value determined for the global mean sea-level rise is (1.46±0.2) mm a⁻¹.     

Optimum design and earthquake-response constrained design of elastic shear buildings

The necessary and sufficient conditions for global optimality and the closed form solution are derived for a problem of minimizing a weighted sum of storey stiffnesses of a shear building subject to a fundamental frequency constraint. A set of higher frequency formulae is derived for optimally designed shear buildings with equal masses. It is shown that, if the weight coefficients are regarded as parameters for adjustment, the distribution of the SRSS estimates of the maximum interstorey drifts can be adjusted so as to coincide with a specified one. The base shear–fundamental period formulae and the base shear–design drift formulae are derived semi-analytically for shear buildings with equal masses on the basis of the optimum design formulae and the SRSS estimates of the maximum interstorey drifts. Some numerical examples are presented in order to illustrate the validity of the proposed method of earthquake-response constrained design.     

区域地震台网地震定位能力分析

本文提出了分析区域地震台网地震定位能力的一种通用方法.在分析过程中考虑了如下事实:当改变地震震级和震源在台网区域内的位置时,能读出 P 震相和 S 震相到时的台站组合也随之改变.作为一个实例,具体分析了北京遥测地震台网的定位能力.北京台网现有19个台站,覆盖面积约为300公里400公里.根据观测资料,建立了确定每个台站检测能力(作为台站仪器放大倍数和地震震级的函数)的经验公式.然后,对每个给定震级和震源位置的可能事件,确定其子台网的构成.在这些子台网的基础上,利用奇异值分解技术,对事先设定的到时数据标准误差计算出震源座标的误差分布和线性化条件方程组的条件数分布.对给定震级(例如,ML=1.0,2.0或3.0),将计算结果绘成等值线图.为了进行比较,还分析了一个包括61个台站的北京台网扩建方案,从而可以预先估计未来台网的地震定位能力.     

Experimental study of near-bed concentration and sediment vertical mixing parameter for vertical concentration distribution in the surf zone

Two formulae for the near-bed concentration(C_a) and the sediment vertical mixing parameter(m) are established based on a large scale wave flume experiment.The advantage of the new formulae is that the turbulent kinetic energy induced by wave breaking can be taken into account;the formula for C_a is in terms of the near-bed,time-averaged turbulent kinetic energy,and the formula for m is in terms of depth-and time-averaged turbulent kinetic energy.A new expression for suspended sediment load also is established by depth integration of the vertical distribution of the suspended sediment concentration obtained on basis of the new formulae.Equation validation is done by comparing the predicted C_a and m to measurements for different types of waves(regular wave,wave group,and irregular wave),and good agreement is found.The advantages of the proposed formulae over previous formulae also are discussed.     

水面蒸发与散热系数公式研究(二)

根据自1976年以来全国水面蒸发与散热研究协作组在我国各典型地区的原体与室内实验资料和大量水文站历史资料,通过理论分析和统计检验,确定了影响水面蒸发的诸因子及其非线性相互作用,引入了新的无量纲参数和公式结构,用实测资料统计确定了公式中的常系数,得到了用开敞湖面一般水文气象资料计算逐日蒸发和散热系数的公式。经全国务典型气候带内务季节湖泊(水库)和受热污染水体上原体观测和室内专题实验共1860组日平均检验,公式的精度高于现有其他公式。全文分两部分,本文刊出第二部分,内容包括:公式的检验;水文气象要素对α的影响;水面散热系数的计算和结语。     

Optimization of laboratory illumination in optical dating

As part of the development of new laboratory lighting, we present a methodological approach applicable to the characterization of any light source intended for illumination in optical dating laboratories. We derive optical absorption cross-sections for quartz and feldspar from published data and compare these with the human eye response. The optimum peak wavelength giving the best clarity for non-dark adapted vision for the least trapped charge loss lies within the wavelength range 590–630 nm; we argue that it is unnecessary to consider dark-adapted vision. The predicted relative decay rates of quartz optically stimulated luminescence (OSL) and feldspar infrared stimulated luminescence (IRSL) signals by an incandescent light bulb and a compact fluorescent lamp (CFL) through an ILFORD 902 filter are first derived. These predicted decay rates are then compared with those of three relevant light-emitting diodes (LEDs); this comparison demonstrates the significant advantage of the LED sources over the filtered light sources, because essentially all of the reduction of both OSL and IRSL signals by the LEDs occurs at wavelengths to which the human eye is most sensitive. We conclude that exposure of quartz and feldspar extracts from various samples to the light from an LED with emission peak at 594 nm results in a ≤1% OSL or IRSL signal loss for a 48-h exposure at a power density of ∼0.2 μW.cm⁻².     

水面蒸发与散热系数公式研究(一)

根据自1976年以来全国水面蒸发与散热研究协作组在我国各典型地区的原体与室内实验资料和大量水文站历史资料,通过理论分析和统计检验,确定丁影响水面蒸发的诸因子及其非线性相互作用,引入了新的无量纲参数(w_e、Pv、Pe)和公式结构,用实测资料统计确定厂公式中的常系数,得到了用开敞湖面一般水文气象资料计算逐日蒸发和散热系数的公式。经全国各典型气候带内各季节湖泊(水库)和受热污染水体上原体观测和室内专题实验共1860组口平均资料检验,公式的精度高于现有其他公式。全文分两部分,这是第一部分,内容包括:影响水面蒸发的土要无量纲参数;感热输送和大气饱和度对蒸发影响的修正;水面蒸发计算公式的结构及其经验系数。     

Exact traveltime computation in multi-layered transversely isotropic media with vertical symmetry axis

An approach to calculate the accurate ray paths and traveltimes in multi-layered VTI media (transversely isotropic media with a vertical symmetry axis) is proposed. The expressions of phase velocity, group velocity and Snell’s law used for computation are all explicit and exact. The calculation of ray paths and traveltimes for a given ele-mentary wave is equivalent to that of a transmission problem which is much easier to be treated with the formulae proposed. In the section of numerical examples, the proce...