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121.
Earthquake probabilities and magnitude distribution (M ≥ 6.7) along the Haiyuan fault, northwestern China 总被引:2,自引:0,他引:2
冉洪流 《地震学报(英文版)》2004,17(6)
Introduction Haiyuan fault is a major seismogenic fault in north-central China. One of the most devastat-ing great earthquake in the 20th century occurred near Haiyuan in northwestern China on Decem-ber 16, 1920. More than 220 000 people were killed and thousands of towns and villages weredestroyed during the devastating earthquake. A 230 km long left-lateral surface rupture zone wasformed along the Haiyuan fault during the earthquake with maximum left-lateral displacement of10 m. Pale… 相似文献
122.
123.
EXPERIMENTAL STUDY ON EFFECTS OF HUMIDITY AND CHEMICAL COMPOSITION UPON IMAGINARY PART OF REFRACTIVE INDEX OF AEROSOL PARTICLES*
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Experimental study is made of the relationship between the imaginary part of refractive index (IRI) of atmospheric aerosol particles and relative humidity,and between IRI and chemical element through the assay of chemical constituents of the particles.Evidence suggests that atmospheric humidity and aerosols' chemical ingredients have great effects on the IRI's and they should thus be considered in the research of the radiation properties of the particles in the atmosphere. 相似文献
124.
The geography information system of the 1303 Hongton M=8 earthquake has been established. Using the spatial analysis function of GIS, the spatial distribution characteristics of
damage and isoseismal of the earthquake are studies. By comparing with the standard earthquake intensity attenuation relationship,
the abnormal damage distribution of the earthquake is found, so the relationship of the abnormal distribution with tectonics,
site condition and basin are analyzed. In this paper, the influence on the ground motion generated by earthquake source and
the underground structures near source also are studied. The influence on seismic zonation, anti-earthquake design, earthquake
prediction and earthquake emergency responding produced by the abnormal density distribution are discussed.
Foundation item: National important fundamental research “The Basic Research of Important Project in Damage Environment” and The important
project “The Seismic Hazard Assessment Research and Anti-earthquake Structure Research” from China Earthquake Administration
during the 10th Five-year Plan.
Contribution No. 04FE1008, Institute of Geophysics, China Earthquake Administration. 相似文献
125.
This article has two purposes. Firstly, a validation exercise of the modal summation technique for the computation of synthetic
strong-motion records is performed for two regions of Europe (Umbria-Marche and south Iceland), using a variety of region
specific crustal structure models, by comparing the predicted ground motion amplitudes with observed motions. It is found
that the rate of decay of ground motions is well predicted by the theoretical decay curves but that the absolute size of the
ground motions is underpredicted by the synthetic time-histories. This is thought to be due to the presence of low-velocity
surface layers that amplify the ground motions but are not included in the crustal structure models used to compute the synthetic
time-histories.
Secondly, a new distance metric based on the computed theoretical decay curves is introduced which should have the ability
to model the complex decay of strong ground motions. The ability of this new distance metric to reduce the associated scatter
in empirically derived equations for the estimation of strong ground motions is tested. It is found that it does not lead
to a reduction in the scatter but this is thought to be due to the use of crustal structure models that are not accurate or
detailed enough for the regions studied.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
126.
Ambiguous Moment Tensors and Radiation Patterns in Anisotropic Media with Applications to the Modeling of Earthquake Mechanisms in W-Bohemia 总被引:3,自引:0,他引:3
Anisotropic material properties are usually neglected during inversions for source parameters of earthquakes. In general anisotropic media, however, moment tensors for pure-shear sources can exhibit significant non-double-couple components. Such effects may be erroneously interpreted as an indication for volumetric changes at the source. Here we investigate effects of anisotropy on seismic moment tensors and radiation patterns for pure-shear and tensile-type sources. Anisotropy can significantly influence the interpretation of the source mechanisms. For example, the orientation of the slip within the fault plane may affect the total seismic moment. Also, moment tensors due to pure-shear and tensile faulting can have similar characteristics depending on the orientation of the elastic tensor. Furthermore, the tensile nature of an earthquake can be obscured by near-source anisotropic properties. As an application, we consider effects of inhomogeneous anisotropic properties on the seismic moment tensor and the radiation patterns of a selected type of micro-earthquakes observed in W-Bohemia. The combined effects of near-source and along-path anisotropy cause characteristic amplitude distortions of the P, S1 and S2 waves. However, the modeling suggests that neither homogeneous nor inhomogeneous anisotropic properties alone can explain the observed large non-double-couple components.The results also indicate that a correct analysis of the source mechanism, in principle, is achievable by application of anisotropic moment tensor inversion. 相似文献
127.
Introduction Sichuan-Yunnan region is a major area with frequent strong earthquakes in Chinese mainland, especially the middle-southern segment of South-North Seismic Zone, where many strong earth-quakes occurred in history. In the past 30 years, Sichuan-Yunnan region has two seismically active periods: one is from Tonghai earthquake in 1970 to Longling-Songpan earthquake in 1976, the other is from Lancang earthquake in 1988 to now. During this two periods, the M=7.7 Tonghai, M=7.1 Dagua… 相似文献
128.
129.
130.
铂族元素的表生地球化学研究进展 总被引:2,自引:0,他引:2
基性-超基性岩及黑色页岩等风化过程中铂族元素发生了活化和迁移。铂族元素在岩体附近土壤、植物和水体等表生介质中的迁移富集特征可以用来寻找岩浆型铂族元素矿床。黑色页岩风化过程中,Os的表生迁移对海洋^187Os/^188Os值上升有重要意义。此外,作为重金属元素,机动车铂族元素催化剂在环境中的释放,也会带来潜在的生态环境和人体健康问题。 相似文献