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991.
992.
闽北地质灾害的分布特征及其成因分析 总被引:1,自引:0,他引:1
通过分析闽北地质灾害与降水特征表明:闽北地质灾害时间分布与降水、尤其是与暴雨的分布一致。其空间分布与地质条件的分布一致,而与年降雨量、3~8月降雨量的分布相反。地质灾害发生数的74.9%均在针叶林及经济林中,95.7%发生在坡度>20°的陡坡处。地质灾害与岩土性质以及岩土结构有一定的关系。当浮土厚度在5m或以上时极易发生地质灾害。因此,闽北地质灾害的发生的主要因素是地质条件,强降雨则是其重要的触发条件,人类活动也是诱发地质灾害的因素之一。文章根据地质条件将闽北的地质灾害按易发程度分为:高易发区、中易发区及低易发区。 相似文献
993.
The statistical analysis of the space–time distributions of acoustical signals emitted from the compressed samples of Westerly granite is presented. The samples were uniaxially loaded in two regimes, one of which included a feedback loop controlled by the current acoustical emission (AE) activity. The distribution of distances between newly-appeared hypocenters follows the power law with the exponent that does not depend on the mode of loading. In both regimes, a transient period of the decorrelated accumulation of damaged sites was revealed between the initial and focal stages of the fracture process. The Hurst analysis indicates a more pronounced trend to planar organization of final damage structure in the case of AE-controlled loading. 相似文献
994.
Statistical occurrence analysis and spatio-temporal distribution of earthquakes in the Apennines (Italy) 总被引:1,自引:0,他引:1
We present two examples of statistical analysis of seismicity conducted by integrating geological, geophysical and seismological data with the aim to characterize the active stress field and to define the spatio-temporal distribution of large earthquakes. Moreover, our data will help to improve the knowledge of the “seismogenic behavior” of the areas and to provide useful information for seismic hazard evaluation.The earthquakes are described by two non-parametric statistical procedures integrating also tectonic-physical parameters to study the spatio-temporal variability.The results show that the areas are characterized by: 1) a stress regime with mainly extensional kinematics; 2) tectonic structures mainly oriented with the active stress field (Shmin = N44° ± 18° in the southern Apennines and Shmin = N50° ± 17° in the central Apennines); 3) cluster distribution of seismicity and 4) a high probability of earthquake occurrence (M > 5.5) in the next 10 years. 相似文献
995.
996.
Analysis of a spatial distribution of landslides triggered by the 2004 Chuetsu earthquakes of Niigata Prefecture, Japan 总被引:15,自引:1,他引:15
On October 23, 2004, a series of powerful earthquakes with a maximum M
w = 6.6 located near the western coast of northern Honshu struck parts of northern Japan, particularly Niigata Prefecture;
these earthquakes were known as the Chuetsu event. Thousands of landslides, as a secondary geotechnical hazard associated
with these earthquakes, were triggered over a broad area; these landslides were of almost all types. The purpose of this study
was to detect correlations between landslide occurrence with geologic and geomorphologic conditions, slope geometry, and earthquake
parameters using two indexes based on Geographic Information Systems (GIS). In the study area, the landslide–area ratio (LAR),
which is defined as the percentage of the area affected by landslides, was 2.9%, and the landslide concentration (LC), the
number of landslides per square kilometer, was 4.4 landslides/km2, which is much more than other reported cases of seismic activity with the same magnitude. This was possibly due to heavy
rainfall just before the Chuetsu earthquakes. Statistical analyses show that LAR has a positive correlation with slope steepness
and distance from the epicenter, while LC is inversely correlated with distance from the epicenter. The Wanazu Formation had
the most concentrated landslide activity, followed by the Kawaguchi, Ushigakubi, Shiroiwa and Oyama Formations, although the
Wanazu Formation occupied only 4.5% of the total area of geological units. With 8.2% of the area affected by seismic landslides,
the Kawaguchi Formation had the highest LAR. It was followed by the Shiroiwa, Ushigakubi and Wanazu Formations with LAR ranging
from 4.6% to 6.0%. For lots of geological subunits, landslides are more frequent in a range of slope angles between 15° and
40°. The susceptibility to landsliding of each geologic unit was thus evaluated to correlate with slope steepness. It was
also noted that the effects of the earthquakes were made far worse by antecedent rainfall conditions induced by a␣typhoon,
and further research emphasizing the role of antecedent rainfall was discussed. 相似文献
997.
复杂表、浅层地震地质条件激发效果的探讨 总被引:1,自引:0,他引:1
在复杂表、浅层地震地质条件区采用常规成孔方式比较困难、成本过高,为改善其激发、接收条件,提高复杂区地震勘探应用效果,选定典型目标区域,结合地震施工因素,对普通炸药(高爆速药柱)、聚能震源弹、地震枪、可控震源四种激发源作了对比试验,同时对检波器的组合接收也进行了试验。从试验资料分析,应优先使用可控震源车进行激发,对可控震源车无法施工的地段(如山坡地带等)采用炸药震源激发,且同等条件下,优先考虑聚能震源弹。 相似文献
998.
曹金亮 《水文地质工程地质》2007,34(3):71-74
长治市崔蒙地区因煤矿采空而引发地面塌陷,塌陷积水而使大量农田弃耕,当地经济发展受到极大的影响。本文在地面塌陷地质灾害勘察并查明地面塌陷现状基础上,分析了崔蒙地面塌陷的形成机理,并通过常规移动延续时间、残余移动变形时间估算结合塌陷区地表移动监测资料分析研究,认为地面塌陷仍将持续,只是变形速度较缓慢,不致诱发地裂缝,继续造成土地破坏或地表水体漏失的可能性较小。 相似文献
999.
In engineering projects such as tunnels, dams, foundations, and slope stability, the strength and elastic properties of the intact rock affect both the project design and the construction operation. It is sometimes expensive and time consuming to perform direct tests to evaluate the engineering properties (such as strength, modulus of elasticity, and Poisson's ratio) of the intact rock. The purpose of this work is to investigate the relationships between the engineering properties of the intact rock and the different types of hardness (Schmidt, shore scleroscope, abrasion, and total hardness), which are relatively cheap and easy to evaluate. In this study, dolomite, dolomitic limestone, and shale rocks were used. For simplicity, linear statistical analyses were performed. The results show that there are good relationships between the engineering properties of the intact rock and its hardness. Also, the results of this study are compared well with the results obtained by other investigators conducted on different types of rocks. 相似文献
1000.
在认真研究生产实际的基础上,采用支持ActiveX Automation技术的Visual Basic 6.0高级编程语言实现了在AutoCAD平台上开发钻孔地质柱状图编图系统,实现钻孔地质柱状图人工编图到计算机自动绘图的飞跃。 相似文献