Spectral characteristics of the seismic hazard between the alps and the dinarides     

L. Peruzza  L. Sirovich  D. Slejko 《Soil Dynamics and Earthquake Engineering》1994,13(3)

Empirical correlations between response spectra, magnitude, distance from the source and geological site conditions are introduced in a regional study of seismic hazard. A 350-year earthquake catalogue is treated by means of the statistics of extremes and both the spectral amplitudes (pseudovelocity) corresponding to a series of frequency bands are separately mapped, and the complete predicted response spectra calculated at some sites. Three kinds of geological site conditions are considered: thick and thin (less than 20 m deep) alluvium, and rock. A particular dependence of the results on the geographical distribution of earthquakes and on their magnitudes is commented. The seismic hazard of the study area is also computed by applying a traditional regression between peak ground velocity, magnitude and distance; a comparison with the seismic hazard given by the frequency dependent psuedovelocity indicates the extent of the uncertainty associated with the common practice of scaling response spectra directly from ground motion parameters.  相似文献   

多重熵Kq和g（λ）谱的研究   总被引：1，自引：0，他引：1  

安镇文  黄玮琼 《地震地磁观测与研究》1998,19(6):45-50

应用分形理论中的多重分形和广义维的推导方法,导出了围绕Ｋ熵附近的涨落谱ｇ（λ）,同时描述了广义熵Ｋｑ和多重动态谱的计算方法,特别是利用实际观测数据探讨地震孕育非线性动力演化过程的复杂性,最后讨论了对地震问题的某些应用。  相似文献   

海拉尔盆地煤及其显微组分的红外漫反射光谱特征   总被引：1，自引：0，他引：1  

黄福堂  冯子辉 《地球化学》1998,27(5):500-506

利用红外漫反射光谱和谱带分离技术,从海拉尔盆地煤及其显微组分的红外漫反射光谱图中,在３１００－２８００ｃｍ＾－１范围内分辨出１２或１３个峰,并确认了结构归属,同时建立了５个反映有机质化学结构组成特征的参数,讨论了煤与显微镜组分的生烃潜能。  相似文献   

地震动滞回能量谱衰减规律研究   总被引：2，自引：0，他引：2  

公茂盛  翟长海  谢礼立  章文波 《地震工程与工程振动》2004,24(2):8-14

本文选用美国西部California州15次较大地震中的266条强地震动记录,利用衰减关系建立了滞回能量谱,分析了场地条件、延性系数、震级及距离等参数对滞回能量谱的影响。研究发现,场地条件对滞回能量谱影响很大,随着场地变软,滞回能量谱变大,与A B类场地相比,C类场地的滞回能量谱平均要高出70％左右,D类场地则要高出170％左右。随着延性系数的增大,滞回能量谱有增大的趋势,尤其是当延性系数由2变到4或6时更为明显,但当延性系数增加到一定程度时,滞回能量谱的差别不大,延性系数为4和6时的滞回能量谱差别不大,甚至在周期较大时,延性系数为6的滞回能量谱反而小于延性系数为4时的滞回能量谱。另外,研究结果表明,大的震级和小的距离对结构产生比较大的滞回能量需求。利用本文结果,可以估计未来地震中结构物所遭受滞回能量的大小。  相似文献   

双规准化地震动加速度反应谱研究   总被引：3，自引：3，他引：0  

徐龙军  谢礼立 《地震工程与工程振动》2004,24(2):1-7

本文提出了双规准反应谱的概念。在统计了美国西部大量强震记录的基础上,分别研究了规准反应谱和双规准反应谱的特性,并进行了详细的对比分析。研究结果表明,双规准反应谱比通常的规准反应谱有更好的规律性,这不仅有利于认识地震动的特性,还可使基于场地的抗震设计反应谱大大简化,更便于广大工程设计人员应用。  相似文献   

施甸5.9级地震强震观测资料的时-频反应谱分析     

郭梦秋  王彬  崔建文 《地震研究》2004,27(3):237-240

通过对施甸5．9级地震在太平等观测点的强震记录进行时一频反应谱计算,给出了三个方向的时一频反应谱图,根据时一频反应谱的特点,结合场地条件,对这些场点的震害情况进行了分析,指出了在结构抗震方面应注意的环节,并对时一频反应谱的应用进行了探讨。  相似文献   

Mineralogical Characterization of Graphite Deposits from Thodupuzha-Kanjirappally Belt, Madurai Granulite Block, Southern India   总被引：1，自引：0，他引：1  

K.R. Baiju  M. Satish-Kumar  H. Kagi  C.G. Nambiar  M. Ravisankar 《Gondwana Research》2005,8(2):223-230

Graphite from deposits occurring in the high-grade metamorphic rocks and their larteritized equivalents of the Thodupuzha-Kanjirappally Belt in Madurai Granulite Block, southern India is structurally fully ordered (crystallite size, Lc₍₀₀₂₎ ranging from 469 to 749 Å), possess high degree of graphitization (DG value ranging from 105 to 267 Å) and reflect crystallization at high temperature (700±100°C). Raman spectra of graphite display profiles corresponding to high crystallinity and high structural ordering. The high temperature crystallinity characteristics of graphite were not obliterated during retrogression of granulites to amphibolite facies gneisses. Preliminary carbon stable isotope results show a spread in isotope values from —11.8 to —26.8 %, which suggest more than one sources for carbon. The lighter carbon isotope values are suggestive of biogenic origin, whereas the heavier ones are probably fluid precipitated graphite.  相似文献   

Topographic characteristics of laboratory induced shear fractures     

Ganglin Chen  Hartmut Spetzler 《Pure and Applied Geophysics》1993,140(1):123-135

The topography of laboratory induced shear fracture surfaces of Westerly granite was studied. Three types of fracture surfaces were examined: (1) a fresh fracture from the shear failure of an intact sample under polyaxial loading (₂ = 40 MPa > ₃ = 15 MPa); (2) a shear fracture subjected to frictional sliding of 100 m under polyaxial loading; (3) a shear fracture subjected to frictional sliding of 800 m under conventional triaxial loading (₁ > ₂ = ₃ = 40 MPa). Both sliding distances are within the range of the grain size of Westerly granite. The results are represented by a power spectral method.Similar to the power spectra from natural rock surfaces, the power spectra of the induced shear fracture surfaces fall off about 2 orders of magnitude per decade increase in spatial frequency. No corner frequency exists in the power spectra over a spatial frequency range from that corresponding to the profile length to the Nyquist frequency. A slope break in the power spectrum was identified, however. It separates a steeper low frequency segment from a less steep high frequency segment. The spatial frequency at the slope break corresponds to a wavelength of several hundred microns which is on the scale of the microcracking and contact breaking on the fractures. Upon re-examining power spectra of natural fault traces and fault surfaces obtained in previous studies, we noted similar slope breaks. We suggest that this slope break may have significant implications in the scaling problem. Both the induced fracture surfaces and natural faults exhibit topographic characteristics different from those of sawcut surfaces, which have been widely used in laboratory rock friction experiments. In the present study, we observed that even a small amount of sliding (less than a grain size) already results in significant mismatches between the paired sliding surfaces in the direction normal to sliding.  相似文献   

超随机特性对地震动谱特性和时间历程的影响   总被引：1，自引：1，他引：0  

徐国栋周锡元  闫维明董娣 《地震工程与工程振动》2005,25(5):6-16

本文从单个地震动样本的角度分析了超随机部分对地震动波形的影响,认为自相关函数噪声部分或功率谱的随机波动部分对地震动波形的影响不大,对地震动的波形起主要控制作用的是地震动的相位谱或相位差谱,而自相关函数的噪声部分（或功率谱的随机波动成分）只对地震动波形起一定程度的调整作用。文中基于平稳随机过程的理论,用蒙特卡罗方法分析了自相关函数噪声项对人工合成地震动振幅和反应谱的影响：由于自相关函数的随机噪声项对地震动总功率或平方和的贡献为零,因此随机噪声项对合成地震动幅值的影响不大,但是由于自相关函数随机噪声项明显改变了地震动功率谱的形状和分布特征,使其出现了明显的波动,也在一定程度上提高了平均反应谱的峰值,从而对平均反应谱也产生一些影响。考虑地震动自相关函数中的随机噪声部分有助于更真实地模拟和反映地震动的真实特性。  相似文献   

Remote sensing D/H ratios in methane ice: Temperature-dependent absorption coefficients of CH₃D in methane ice and in nitrogen ice     

W.M. Grundy  S.J. Morrison  M.J. Bovyn  D.M. Cornelison 《Icarus》2011,212(2):941-949

The existence of strong absorption bands of singly deuterated methane (CH₃D) at wavelengths where normal methane (CH₄) absorbs comparatively weakly could enable remote measurement of D/H ratios in methane ice on outer Solar System bodies. We performed laboratory transmission spectroscopy experiments, recording spectra at wavelengths from 1 to 6 μm to study CH₃D bands at 2.47, 2.87, and 4.56 μm, wavelengths where ordinary methane absorption is weak. We report temperature-dependent absorption coefficients of these bands when the CH₃D is diluted in CH₄ ice and also when it is dissolved in N₂ ice, and describe how these absorption coefficients can be combined with data from the literature to simulate arbitrary D/H ratio absorption coefficients for CH₄ ice and for CH₄ in N₂ ice. We anticipate these results motivating new telescopic observations to measure D/H ratios in CH₄ ice on Triton, Pluto, Eris, and Makemake.  相似文献