上海地震台阵标定及结果分析

阐述了台阵的地震定位原理和建立台阵标定数据库的必要性。说明了如何利用上海地震台网资料和上海地震台阵建成后的资料建立台阵标定数据库，最后，对上海台阵标定的结果进行了导致定位误差的横向速度变化的位置和范围的讨论。     

利用上海台阵对常熟2001年2002年震群的精定位

2001年6月上海台阵正式运行,上海台阵的建立提高了上海及周边地区的地震监测能力.本文着重在定位方法和震相判读上,充分利用上海台阵整体观测系统的优势和台阵独特的数据处理方法,对常熟2001年和2002年二次小地震序列进行了精确定位.对精确定位的结果进行了对比与分析,并以此为基础,对常熟地区及周边的地质构造等进行了解释与推断.     

海拉尔地震台阵噪声源调查

利用海拉尔地震台阵位置资料,选取台阵半径50 km范围,通过实地摸排和GPS仪定位方法,判断台阵周围有无国际标注的各大噪声源,同时计算噪声源与台阵的距离,分析台阵所属9个子台环境噪声水平,并将现今噪声功率谱与2000年时进行对比,汇总结果,并对台阵环境噪声水平进行评价。结果表明,海拉尔地震台阵周围有6类噪声源,其中工业设施和公共交通对台阵噪声水平的影响集中在高频段,但对监测能力影响不大;根据地震计安放位置与干扰源的最小距离进行评价,得出7个子台噪声源水平达到Ⅰ级台站环境地噪声水平,B₄、B₅子台处于Ⅱ级台站环境地噪声水平,台阵噪声水平总体处于良好状态,不影响仪器的正常运行。     

兰州台阵响应函数及不同方位小地震事件FK分析结果

计算了兰州台阵不同频率的台阵响应函数,对台阵附近不同方位的4个小震进行了FK分析。结果显示兰州台阵2 Hz以下的台阵响应函数在原点附近呈现出对称的单主峰图样,而高于2Hz时台阵响应函数出现较多旁瓣,表明该台阵对于2 Hz以下的信号具有较好的分辨能力。小震的FK分析结果表明,根据甘肃省地震局地震目录和IASP91速度模型计算得到P波方位角和慢度与FK分析的结果总体上比较一致,但也存在一定差别,这种差别可能由所使用的理论模型和当地模型有差别以及未做台阵校正所引起。     

野外台阵建设与维护常见故障分析处理

结合野外台阵工作的实践情况,对台阵选址、建设及后期仪器维护过程中出现的问题进行分析,并给出了相应的处理方法。     

兰州地震台阵监测能力研究

利用兰州地震台阵与兰州地震台数字化近两年的资料,对地震震相特征和震级进行对比分析,结果发现：地震记录震相特征基本相同,台阵有压低干扰背景和突出地震波信号的功能,说明台阵对记录较微弱地震有优势;在震中距小于1 000 km的范围内,兰州台阵的监测能力较明显高于兰州台,而震中距大于1 000 km时,兰州地震台阵与兰州地震台的监测能力相当.     

台阵地震学方法及在中国IMS台阵的应用研究

中国的地震台阵建设与发展比国外晚了几十年.目前国内地震台阵正在不断地建设,而缺少的就是台阵技术,如能够把已有的台阵技术应用到我国的台阵中,就可以让台阵发挥它们应有的价值.作者根据国外的参考文献主要讨论了台阵地震学的主要技术方法并把这些方法应用到中国的IMS台阵,并给出了应用实例.结果表明,地震台阵使我们对地下结构的研究更加精细,使我们对微弱信号的识别更加轻松.如果我国现有台阵都能应用台阵地震学技术将对我国地震学和地球物理学的发展起到很大的推动作用.     

格尔木地震台阵勘址数据分析与台阵布局设计

为了增强西部地区的地震监测能力, 中国拟在格尔木地区建立一个小孔径地震台阵。 本文对台阵勘址数据进行了噪声与信号的相关性分析, 得到地震监测的最佳台间距。 结果表明, 对于近震和区域震的监测, 该台阵子台间距最好小于500 m, 对于远震的监测, 台站组合间距应为1500～2000 m。 最后将勘址布设的台阵作为初选台阵进行了台阵响应计算, 计算显示, 台阵响应的主瓣在NW-ES方向较窄, 表明对来自该方向事件的慢度分辨率较高; 由于呈“L”型分布, 该初选台阵确定某些方向地震的方位角较好, 但检测其他方向事件的方位角精度不高, 这可以通过台阵校正进行改善; 台阵响应中出现的多处侧瓣是由于子台间距较大造成的。     

兰州地震台阵环境噪声调研分析

随着我国社会经济的发展,地震台站观测环境破坏日益严重。对兰州地震台阵环境噪声进行调研,定量分析并提供该台阵与国际标注各大干扰源的直线距离,以充分了解各干扰源对地震台阵的影响程度。结果发现,兰州地震台阵目前基本达到Ⅰ级台站环境噪声水平,满足台阵观测条件。     

上海地震台阵电缆的铺设

前言一般来说 ,台阵各子台地震计所检测的地震信号是通过有线或无线的方式传输汇集到位于台阵附近的数据中心。如德国格兰芬堡台阵分为 3个子台阵 ,采用有线的方式先将各子台阵每一子台的地震信号传输到子台阵中心 ,然后再将汇集到各子台阵的地震信号再分别传输到埃尔兰根的台阵中心。又如加拿大黄刀台阵的初期 ,各子台的地震信号输出采用悬挂在木制三角架上的电缆传输到附近的控制中心。 1 986年加拿大政府对黄刀台阵进行了重大更新 ,除了在台阵安装不同频带的地震计外 ,还采用高分辨的数字化输出 ,并将地震数据通过 UHF数字无线遥测传输…     

Vertical motion and diabatic heating over the Indian monsoon region during the Bay of Bengal depression of 5–8 July, 1979

The vertical velocity, , and the diabatic heating were computed at 800, 600, 400 and 200 mb surfaces using the Omega equation. The highest contribution to is from the diabatic heating produced by condensation associated with the precipitations appearing to be the main source of diabatic heating. The net radiative cooling and the thermal advection in the upper troposphere over the warm anticyclone result in diabatic cooling over the eastern part of the Bay of Bengal and adjoining northern and eastern regions.List of Symbols Used C _p Heat capacity at constant pressure - f Coriolis parameter - g Acceleration due to gravity - P Atmospheric pressure - Q Diabatic heating rate per unit mass - R Gas constant of air - S Static stability parameter - t Time - U, V Zonal and meridional wind components - Specific volume - Relative vorticity - Absolute vorticity - Potential temperature - Geopotential - Vertical velocity (dP/dt) - ₁ Adiabatic vertical velocity - ₂ Vertical velocity due to certain forcing - ₃ Diabatic vertical velocity - Isobaric gradient operator - ² Laplacian operator - J(A, B) Jacobian operator     

Seismic excitation of the polar motion, 1977–1993

The mass redistribution in the earth as a result of an earthquake faulting changes the earth's inertia tensor, and hence its rotation. Using the complete formulae developed byChao andGross (1987) based on the normal mode theory, we calculated the earthquake-induced polar motion excitation for the largest 11,015 earthquakes that occurred during 1977.0–1993.6. The seismic excitations in this period are found to be two orders of magnitude below the detection threshold even with today's high precision earth rotation measurements. However, it was calculated that an earthquake of only one tenth the size of the great 1960 Chile event, if happened today, could be comfortably detected in polar motion observations. Furthermore, collectively these seismic excitations have a strong statistical tendency to nudge the pole towards 140°E, away from the actually observed polar drift direction. This non-random behavior, similarly found in other earthquake-induced changes in earth rotation and low-degree gravitational field byChao andGross (1987), manifests some geodynamic behavior yet to be explored.     

跨断层桥梁抗震若干问题探讨

从断层时间尺度、活动性、场地效应等方面阐述跨断层桥梁的定义与内涵;从"功能性"、"制约性"、"地表破裂变异性"、"设计缺陷"4方面分析跨断层桥梁"不得不"面临较大的地震破坏风险的原因;最后以1979年Imperial Valley地震中El Centro台阵收集到的强震记录为基础,对断层破裂强震记录特征及地震动传播机理进行分析,研究断层两侧地面运动分布规律,建议跨走滑断层桥梁的地震动输入方向。本文研究结果对促进跨断层桥梁抗震设防具有借鉴意义。     

An investigation of analysis of variance as a tool for exploring regional differences in strong ground motions

The statistical technique known as analysis of variance is applied to a large set of European strong-motion data to investigate whether strong ground motions show a regional dependence. This question is important when selecting strong-motion records for the derivation of ground motion prediction equations and also when choosing strong-motion records from one geographical region for design purposes in another. Five regions with much strong-motion data (the Caucasus region, central Italy, Friuli, Greece and south Iceland) are investigated here. For the magnitude and distance range where there are overlapping data from the five areas (2.50 M_s 5.50, 0 d 35 km) and consequently analysis of variance can be performed, there is little evidence for a regional dependence of ground motions. There is a lack of data from moderate and large magnitude earthquakes (M_s > 5.5) so analysis of variance cannot be performed there. Since there is uncertainty regarding scaling ground motions from small to large magnitudes whether ground motions from large earthquakes are significantly different in different parts of Europe is not known. Analysis of variance has the ability to complement other techniques for the assessment of regional dependence of ground motions.     

纵波质点的运动与界面的反射

在原有波动学的基础上,通过对波传播质点的运动和作用进行研究,提出了波传播的力学作用不仅有因形变产生的应力,还存在着另一种由速度决定的不同形式的力——“动作用力”.动作用力才是波传播的根本动力.由“动作用力"和形变应力确立波的动力学方程,由这个方程,又可确定质点的运动规律.质点在波传播中一般并不作弹性振动,质点沿一个方向运动进行能量传递后,只作微弱的回复运动.质点这种运动特点才符合能量守恒.质点这种运动特点决定不同的界面性状有不同形态的反射波.     

Collectors强震动台网数据处理系统的设计及实现

介绍了"Collectors强震动台网数据处理系统软件"的整体设计思路和功能模块的实现过程,统计了近2年所接入的近千个强震动台站的数据汇集及产出情况,重点统计了近2年云南、四川、新疆发生的5.0级及以上地震的地震事件记录回收及强震动参数产出的用时情况。结果表明:系统软件能7×24 h连续、稳定、可靠、高效地自动化运行,在处置地震事件时,一般能在2~10 min内陆续完成地震事件的自动回收和强震动参数的自动产出,速报能力由软件推广前的小时级别跃升至分钟级别。     

An explanation of the large PGA value of 2013 Ms7.0 Lushan earthquake at 51BXD station through topographic analysis

In Ms7.0 Lushan earthquake, a large amount of strong ground motion recordings were collected. In this paper, we analyze the recordings carefully. The abnor- mality of ground motion recordings is identified through a log linear regression. In the station of 51BXD, the PGA value has exceeded 1 g, which is the biggest peak ground acceleration （PGA） value obtained from all recordings in this earthquake. The log linear relation shows the PGA value in this station is abnormally large. As this station is located on the footage of a hill, the topographic amplifi- cation factor is explored in order to explain this abnor- mality. Through 3D numerical modeling using spectral element method with transmitting boundary conditions, the amplification factor is quantized. In this station, the topo- graphic amplification is highly polarized in the direction of East-West which agrees with the empirical recordings. This research result suggests us in future directionality of topographic amplification should be considered in the aseismic design.     

Rupture Directivity During the September 7, 1999 (<Emphasis Type="Italic">M</Emphasis><Subscript><Emphasis Type="Italic">w</Emphasis></Subscript> 5.9) Athens (Greece) Earthquake Inferred from Forward Modeling of Strong Ground Motion

The empirical Green's functions technique is applied to simulate strong ground motion records from the September 7, 1999, Athens earthquake. Information on the fault parameters from previous independent studies has been used and several scenarios were examined, in regard to the location of the starting point of the rupture, by comparing the synthetic records with the corresponding observed ones, through a residual function and a correlation function. The results show that the rupture started at the deepest, 4–5 km, part of the fault from its western edge. This hypocenter was then used, in combination with the initial fault model, to stochastically simulate the strong ground motion during the Athens main shock, in terms of peak-ground acceleration at hard rock. The results show that directivity might have significantly contributed to the destructiveness of this earthquake at specific parts of the Athens Metropolitan area.     

新疆"十五"强震动台网建设

在简要介绍“十五”中国数字强震动台网建设项目总体框架的基础上,着重介绍了与新疆“十五”数字强震动台网建设有关的固定强震动台网和乌鲁木齐市地震烈度速报台网的选台原则、规模、分布、设备配置、数据通讯、维护运行模式及其在防震减灾中的作用。新疆“十五”数字强震动台网的建成,将使新疆地区的强震动观测在台网规模和密度、观测环境和技术水平、强震动记录的获取能力和质量、数据处理速度和信息发布功能等方面跨上一个新台阶。     

Sealing law of far-field spectra based on observed parameters of the specific barrier model

A set of acceleration source spectra is constructed using the observed parameters of the specific barrier model of Papageorgiou and Aki. The spectra show a significant departure from the ²-model at the high frequency range. Specifically, the high frequency spectral amplitudes of seismic excitation are higher as compared to the level predicted by the ²-model. This is also supported by other observational evidence. The high frequency amplitudes of acceleration scale proportionally to the square root of the rupture areaS, to the rupture spreading velocityv, and to the local strain drop (/) (=strain drop in between barriers). The local strain drop in between barriers is not related in a simple way to the global strain drop, which is the strain drop estimated by assuming that it is uniform over the entire rupture area. Consequently, the similarity law does not apply. Using the source spectra which we constructed, we derive expressions for high frequency amplitudes of acceleration such asa _rms anda _max. Close to the fault both are independent of fault dimensions and scale as (/µ)(f)^1/2, while away from the fault plane they scale asW ^1/2(/µ)(f)^1/2, whereW is the width of the fault and f is the effective bandwidth of the spectra.