40Ar-39Ar Spectra of Alunite from Phreatic Craters in the Muine Volcano, Hokkaido, Japan

Abstract. ⁴⁰Ar-³⁹Ar analyses of two alunite samples from phreatic craters in the Pliocene Muine volcano in southwest Hokkaido, Japan, were carried out. The alunite with 17.4 permil δ³⁴S_{V_CDT} value in hydrothermal breccia from the Nagaoyama crater and that with 14.3 permil δ³⁴S_{V_CDT} value in silicified andesite from the Konuma crater give total fusion ages of 1.40 ± 0.04 Ma (la uncertainty) and 1.24 ± 0.08 Ma, respectively. However, the spectra of these samples indicate they have been effected by thermal overprinting and/or the existence of excess argon. These preliminary ⁴⁰Ar-³⁹A analyses suggest that the alunite underwent multiple hydrothermal activity by magmatic gas and vapor subsequent to the main hydrothermal activity.     

几种push-over分析方法对比研究

Push-over方法是一种静力非线性计算方法，是近年来在国内外得到广泛研究应用的用于评价结构抗震能力的新方法。采用这种方法计算结构的弹塑性地震反应将会逐渐为广大的工程设计人员所接受，但目前对于这种用静力的方法去预测结构的动力反应，其可靠性如何一直是许多学者所关注的，而且对于现有的几种方法的优劣也没有给出综合的评价。本文在国内外有关理论和方法的基础上，对几种push-over分析方法进行了简要评述，并通过分析计算对其中有代表性的能力谱方法、位移影响系数法和适应谱push-over方法进行了详细的对比研究。指出了其中存在的问题，试图寻找并推荐一种比较好的方法。结果能够实现这一目标，对于push-over方法的发展将会有一定的推动作用。     

江苏及邻区地震时序的多重分形特征及其预报意义

研究了江苏及邻区1970年以来5．5级以上地震的多重分形特征，着重用推广GP法研究了地震前后多重分形的广义维数谱Dq和奇异性谱f(a)。研究结果表明：所有震例的广义维数谱和奇异性谱均经历了远离地震时，异常出现时和异常消失时的三个特征变化阶段，异常出现的时间在震前半年至一年半内；多数震例异常在震前几个月内回返恢复，少数在震后数个月内恢复。上述结果说明利用地震时序的多重分形特征对于该地区半年至一年尺度的中强地震预报是有意义的。     

Characteristics of strong ground motion during the 1999 Chi-Chi earthquake (Taiwan) and large aftershocks: comparison with the previously established models

In the Taiwan region, the empirical spectral models for estimating ground motion parameters were obtained recently on the basis of recordings of small to moderate (5.0≤M_L≤6.5) earthquakes. A large collection of acceleration records from the recent M_L 7.3 (M_W 7.6) Chi-Chi earthquake (20 September, 1999) makes it possible to test the applicability of the established relationships in the case of larger events. The comparison of ground motion parameters (peak accelerations and response spectra), which were calculated using the stochastic approach based on the modeled Fourier amplitude spectra, and the observed data demonstrates that the models may be successfully used for ground motion prediction for earthquakes of magnitudes up to M_L=6.8–7.0 and hypocentral depth more than 10 km. To satisfy to the peculiarities of ground motion during shallow (depth less than 10 km) and larger (M_L>7.0) events, the models were revised.     

13C high resolution solid state NMR spectra of Chinese coals

Several typical exinites in China including alginite, cultinite, suberinite and bituminite are analysed by means of¹³C high solution solid state CP MAS TOSS NMR spectra to determine their chemical structures and hydrocarbon potential. Thermal simulation solid products (TSSP) of hydrogen-rich coals are studied to discuss the generation and expulsion mechanism of coal-generating hydrocarbon. The preliminary results are quite encouraging, wntaining useful information about genesis of coal-generating oil and gases. Project supported by the “85–102” Chinese National Key Science and Technology Project.     

Soil classifications for estimating site-dependent response spectra and seismic coefficients for building code provisions in western Kentucky

One hundred thirty-four horizontally polarized shear-wave (SH) seismic soundings have been performed in the Jackson Purchase Region of western Kentucky. These data have been used to derive the thicknesses and shear-wave velocities for the various impedance horizons in the upper 30 m of the soil column at each site for the purposes of general land-use management and loss estimation in the event of an earthquake. A generalized seismic susceptibility soil classification scheme adopted by the Borcherdt (1994a,b) was fit to the results. Soils across western Kentucky were found to be either SC-II or SC-III soils, correlating to gravelly soils having soft to firm consistency and stiff clays to loose/dense sands, respectively.     

模拟酸雨对水稻叶片反射光谱特性影响的初步研究

本文研究了模拟酸雨对水稻叶片反射光谱特性的影响。结果表明：模拟酸雨会引起水稻叶片反射光谱的可见光区和中红外区的反射率升高，近红外区的反射率降低，相应的反射率比值也随之变化，一阶和二阶微分光谱蓝移，且上述变化的程度与酸雨的酸度、水稻的品种和生育期有关。这一结果也表明遥感技术监测酸雨污染作物是可行的。     

Attenuation characteristics of ground motions in northern China

Four recently developed attenuation models are calibrated by using a very limited amount of strong motion data recorded in China. The research shows that the attenuation characteristics of the earthquake shaking in northern China are similar to those in the western US. The supporting evidence includes Q factors, preliminary results of kappa values, stress drop, shear wave velocity profile in the shallow earth crust, areas enclosed by the isoseismals of Modified Mercalli Intensity V. From these comparisons of different attenuation models, it is recommended that the Crouse and McGuire spectral attenuation model could possibly be used for northern China. Funded by: The Hong Kong Polytechnic University, and partly supported by NSFC (Grant No.59678048)     

Spectroscopic Observations of New Galaxies with a UV Excess. III

The results of the spectroscopic observation of 23 galaxies with a UV excess from Kazarian's lists are presented. The spectra were obtained on the 2.6-m telescope of Byurakan Observatory with a Byu FOSC-2 camera. Two grisms, red and green, were used in the observations. Emission lines are observed in the spectra of 21 of the galaxies.     

Nearshore bedform instability in the eastern entrance to the Qiongzhou Strait,South China Sea

Six bathymetric transect profiles were drawn from the nautical charts of 1942, 1962 and 1992 to show that the nearshore seabed remained unstable during the recent 50 years in the middle channel of the eastern entrance to the Qiongzhou Strait, South China Sea. Our results demonstrate that the multi-year averaged seabed aggradational rate was 25 cm/a and erosion rate was 12.5 cm/a. Lateral migration rate of the sea bedform identified from the historical contours was about 100 m/a in the SE direction. Bedform measurements were made using GPY Shallow Seismic Profiler in 1994 in the study area. The records revealed four types of distinctive bedforms that were composed of fine and medium sands. The average spacing of large and small-scale sand dunes is 416 m and 144 m and the average height remains 8.8 mand 4.9 m. The spatial and temporal equilibrium-range spectra of numerical bedform records were applied to estimate short term celerity of bedform movement. Results indicate that large and small dunes migrated at an average celerity of 0.02 cm/hr eastward and 0.09 cm/hr westward in the calm sea weather, while their celerity can reach 53 cm/hr eastward during typhoon season and is only 0.008 cm/hr westward when NNE winds prevail. The results also show that the larger the temporal and spatial scale is, the smaller the bedform movement celerity appears. On the other hand, the smaller-scale bedform celerity of the present study is much greater than that of flume, empirical and theoretical data, but close to the wind tunnel and field-measured data of similar grain size.