台湾海峡7.3级地震强震记录分析

介绍了１９９４年９月１６日台湾海峡发生了７．３级强烈地震时，在汕头国际大酒店内的强震加速度记录，这是我国在软弱地基高层建筑结构（２６层）上首次获得的７级以上的强震加速度记录，文中介绍了对记录分析得到的最大加速度（及积分成速度，位移）振动周期等基本结果。     

新丰江强震记录处理

本文介绍了加速度记录处理的内容和方法,包括零线校正、仪器性能校正、反应谱和富氏谱的计算;给出新丰江强震加速度记录的分析结果;建议在大坝设计中,适当提高动力放大倍数的值.     

水工建筑物强震动加速度记录的分析处理

从工程应用角度详细介绍水工强震动加速度记录正确处理分析的方法与原理.主要介绍了震源的评估原理,强震动加速度记录预处理过程中单位换算、奇异点剔除、基线校正、滤波除噪等步骤的方法原理,后处理分析中一次、二次积分、谱分析原理.阐述了利用强震动加速度记录进行震害快速评估原理.文中以二滩拱坝强震监测台阵监测到的一次强震加速度记录的处理过程为例,以图表形式直接明了地强调指出了强震动加速度记录处理中容易发生错误的过程,并提出相应的处理方法.     

电流计记录式强震加速度仪记录的失真及其校正

本文详细地研究了电流计记录式加速度仪的频率响应失真对强震加速度记录的影响,提出了对失真记录进行校正的两种方法:假想摆法和微分-积分法。计算与实验结果表明:这两种方法都能给出满意的结果,均可推广使用。作为实例,对1976丰11月15日宁河地震(M_L:7.1)的强震加速度记录进行了校正,最大校正量(幅值)达35％。此外,还对比了由失真加速度记录和校正加速度记录计算的位移曲线,表明这种校正工作对获得准确的地震位移曲线是十分必要的。     

同一台基的强震仪记录与地震仪记录对比研究

本文根据时域实时方法,对辽宁省共同台基的数字宽频带加速度记录和地震仪速度型记录进行相互仿真,并做了对比分析。结果表明,可以由加速度记录仿真得到真实的速度与位移时程;同样,地震仪速度型记录通过仿真也能得到加速度时程。由此可见,强震观测和地震观测在一定范围内是可以相互替代的。     

澜沧-耿马强震加速度记录

本文介绍在1988年11月云南省澜沧-耿马大地震中中国建筑科学研究院工程抗震研究所和云南省地震局在滇南的联合强震观测台网。以及两单位的流动观测台站在极震区所获取的主震和大量余震加速度记录。文中展示了Ms=7.6的主震时,距震中142.5公里的景洪台站的远场地面加速度记录;还展示了Ms=6.7的强余震时,距震中仅为3.8公里的竹塘站的近场地面加速度记录,其水平向最大加速度为0.55g,竖向最大加速度为0.39g。文中同时对两组记录作了反应谱和β谱分析并参照新修订的建筑抗震设计规范GBJ11-89所提出的设计反应谱,对近震反应谱和远震反应谱的不同特征作了比较分析。最后对加强强震观测的对策提出了看法。     

共同台基的强震仪记录与地震仪记录对比研究

本文根据时域实时方法,对辽宁省共同台基的数字宽频带加速度记录和地震仪速度型记录进行相互仿真,并做了对比分析.结果表明,可以由加速度记录仿真得到真实的速度与位移时程;同样,地震仪速度型记录也能通过仿真得到加速度时程.由此可见,强震观测和地震观测在一定范围内是可以相互替代的.     

施甸地震强震观测记录及其初步分析

在2001年4月12日发生的施甸5．9级地震中，依据地震预报意见布设在滇西的短临跟踪临时强震台网获取了该次地震的强地面运动记录，最大加速度峰值达515gal(未校正），获取大于500gal主震记录，这在我国还是首次，对记录的情况作了简要的介绍。     

乌恰地震加速度记录特征研究

研究了1985年乌恰余震取得的加速度记录,从地质及地球物理的角度探讨一些加速度异常点。分析了记录的峰值加速度与震害及场地烈度的对应关系。对比了竖向和水平向加速度、速度反应谱及谱与震级的变化特征。     

强震加速度记录的校正

本文是为“新丰江强震加速度记录分析”而准备的。文中选取恰当例子说明强震加速度记录校正是个极为重要的问题.着重论述了强震加速度记录的校正内容、方法及其原理。文例亦证明校正工作已收到良好效果.     

强震观测网、高灵敏度地震观测网、地中强震观测网、宽频带地震观测网

阪神·淡路大震灾后 ,日本着手对原有的地震观测体制作彻底改革 ,多项全国性配置地震计的计划同时开始启动。地震引起的地面晃动的程度不尽相同 ,无感微小地震引发的晃动仅有 0 .0 0 1 μm,频率为1 0 Hz;巨大地震引起的地面晃动的幅度高达 2～ 3 m,周期也有几十秒。虽说都称之为地震计 ,但由于地震动的振幅和频率涉及的范围太大 ,所以应针对观测对象选用不同类型的地震计。下面介绍不同类型的观测网。1　强震观测网 ( K- NET)无论大地有多大的晃动都能将其准确记录下来的地震计称之为强震计。它构造坚实 ,信号明确 ,通常设置在地表 ,对了…     

Age, geology, geophysics, and geochemistry of Mahukona Volcano, Hawai`i

The size, shape, and magmatic history of the most recently discovered shield volcano in the Hawaiian Islands, Mahukona, have been controversial. Mahukona corresponds to what was thought to be a gap in the paired sequence (Loa and Kea trends) of younger Hawaiian volcanoes (<4?Ma). Here, we present the results of marine expeditions to Mahukona where new bathymetry, sidescan sonar, gravity data, and lava samples were collected to address these controversies. Modeling of bathymetric and gravity data indicate that Mahukona is one of the smallest Hawaiian volcanoes (～6,000?km³) and that its magmatic system was not focused in a long-lived central reservoir like most other Hawaiian volcanoes. This lack of a long-lived magmatic reservoir is reflected by the absence of a central residual gravity high and the random distribution of cones on Mahukona Volcano. Our reconstructed subsidence history for Mahukona suggests it grew to at least ～270?m below sea level but probably did not form an island. New ⁴⁰Ar–³⁹Ar plateau ages range from 350 to 654?ka providing temporal constraints for Mahukona’s post-shield and shield stages of volcanism, which ended prematurely. Mahukona post-shield lavas have high ³He/⁴He ratios (16–21?Ra), which have not been observed in post-shield lavas from other Hawaiian volcanoes. Lava compositions range widely at Mahukona, including Pb isotopic values that straddle the boundary between Kea and Loa sequences of volcanoes. The compositional diversity of Mahukona lavas may be related to its relatively small size (less extensive melting) and the absence of a central magma reservoir where magmas would have been homogenized.     

The Yecheng,Xinjiang, China,earthquake of February 14, 1980

In this study, we have checked the location and focal depth of the Yecheng earthquake (m _b = 6.0, maximum intensity VII) of February 14, 1980. The result shows that this is an intermediate event with a focal depth of 90 km. The microepicenter is located at 36. 4°N, 76, 9°E, while the macroepicenter is at 37.3°N, 76.9°E, 90 km to the north of the microepicenter. This is the first destructive intermediate event in China which led to a damage as severe as of intensity VII. The focal mechanism of the event is determined to be of thrust type. Combined with the analysis of seismological and geological data in surrounding area, the possible relation between the event and plate movement has been discussed. The result in this paper indicates that in some particular place, the destructive effect of intermediate event should be considered in seismic hazard assessment.     

Sun, climate, hunger, and mass migration

Paleoclimatic studies indicate four epochs of global cooling during the last 4 000 years, i. e. during the few centuries before and after 2000 BC, 800 BC, 400 AD, and 1 600 AD; the quasiperiodicity corresponds to cyclic variation of solar activity. Global temperature changes influenced regional precipitation patterns: Northern Europe was wetter while the middle- and low-latitude lands were more arid during colder epochs. Both sets of cold climatical conditions were unfavorable for agricultural production. Historical records show that large demographic movements in history took place because of crop failures and mass starvation, rather than escaping from war zones. The “wandering” of the Germanic tribes during the first two or three centuries of the Christian Era is one example. Whereas the accelerated release of carbon dioxide from the burning of fossil fuels is ultimately to cause global warming, historical evidence indicates, however, that global warming has been on the whole a blessing to mankind. Global cooling, on the other hand, has curtailed agricultural production and has led to famines and mass migrations of people. Perhaps the most important task at the present is not so much computer-modelling of greenhouse effect on global climate, but water-management and agricultural researches to insure food-supply for an everincreasing world population.     

Physical properties,vitrinite reflectance,and microstructure of coal,Taiyuan Formation,Qinshui Basin,China

In this study, we experimentally established the relationship between physical properties, vitrinite reflectance, and microstructure of coal, Taiyuan Formation, Qinshui Basin, China using representative coal samples collected from three different mines via the rock mechanics testing system (MTS). We analyzed the organic macerals, vitrinite reflectance, and microstructure of 11 coal samples using petrography and scanning electron microscopy (SEM). The experimental results suggest that (1) the elastic parameters can be described by linear equations, (2) both P-and S-wave velocities display anisotropy, (3) the anisotropy negatively correlates with vitrinite reflectance, and (4) the acoustic velocities and Young’s modulus are negatively correlated with the volume of micropores. The derived empirical equations can be used in the forward modeling and seismic inversion of physical properties of coal for improving the coal-bed methane (CBM) reservoir characterization.     

Spatial distribution,source apportionment,and associated risks of trace metals (As,Pb, Cr,Cd, and Hg) from a subtropical river,Gomti, Bangladesh

Sediment samples from the Gomti River basin were investigated to determine and evaluate trace metal concentrations,their biological effect,and potential ecological and human health risks for adults and children.The mean concentrations of trace metals were organized in the descending order of mercury(Hg)(0.08 mg/kg)>chromium(Cr)(0.06 mg/kg)>lead(Pb)(0.05 mg/kg)>arsenic(As)(0.02 mg/kg)>cadmium(Cd)(0.01 mg/kg).The current study illustrated that metals were attributed to the area from natural sources and different anthropogenic sources especially from industries.However,the concentration levels were lower than the sediment quality guidelines(SQGs)based on the effect-range classifications of threshold effect concentration(TEC)and probable effect concentration(PEC).Therefore,the concentration of the elements showed no adverse biological effects on aquatic organisms.The evaluated potential ecological risk index also revealed the low toxicity to the aquatic environment.Moreover,the applied sediment quality indices,geo-accumulation index(Igeo),contamination factor(CF),and contamination severity index(CSI)suggested that the contamination levels of the elements were in the acceptable range,and the contamination had not notably impacted on the sediment quality.The risk index(HI)concerning age groups was significantly less than the threshold limit of 1 indicating that the contamination had no non-carcinogenic risk effect.The total carcinogenic risk(TCR)was less than a risk value of 1×10⁴.Hence,the current study suggests that immediate remediation is not required due to an absence of alarming conditions in the study area.Proper monitoring of the attribution of the metal elements should be done for the betterment of human and environmental health。