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171.
华南滨海断裂带地震危险性的数学模拟 总被引:5,自引:1,他引:5
华南滨海断裂带是南海北部规模巨大的活动断裂,其地震危险性的确定将为地震几地震工程提供地质背景依据,应用二维有限元分析和正交设计法反演南海北部及其今近地区的构造应力场,探讨可能发震的危险地段。研究结果表明,滨海断裂带的某些地段,尤其是滨海断裂带被NW向断裂切割的部位有一定的地震危险性。南海北部地区最主要的地震威胁来自巴士系断裂带和珠江口盆地南缘的NWW向断裂带,对华南滨海断理解带潜在的地震危险性不宜 相似文献
172.
应用考虑震级不确定笥和资料完整性估计地震危险性参数的极大似然法,分别采用1940年和1070年至1993年完整的地震资料,计算了汾渭地震带及陕南地区的地震危险性参数。结果表明:利用近几十年来的完整地震资料结合研究区历史上发生的最大地震,可以得到较为可靠的地震危险性参数;参数敏感性分析表明,完整震级不确定性对β的影响较小;随震级不确定性的增大地震年发生率减小;在资料完整的前提下,震级下限在一定范围内 相似文献
173.
本文根据极值理论建立了烈度超越给定值Ij的平均重现期公式,根据最大熵原理建立了未来T年烈度超越给定值Ij的概率和烈度超越给定值Ij的平均重现期之间的关系式。利用1022─1993年的地震资料,计算了临汾(36.10°N,111.50°E)周围4级以上地震在临汾造成的烈度,绘制了未来100年临汾的烈度超越概率曲线(地震危险性曲线)。结果表明,计算场地烈度的极值理论方法可作为地震危险性分析的综合概率法的补充和验证。 相似文献
174.
巴基斯坦卡拉奇─海得拉巴区域地震危险性预测 总被引:1,自引:0,他引:1
Shahid A. Khan 《地震研究》1995,(3)
本文讨论了巴基斯坦的地震构造,潜在震源和历史与现代地震活动性,并在此基础上使用确定性和概率性两种方法计算了各发震断层50年内最大可能的地震在卡拉奇和海得拉巴两城市将引起的地面峰值加速度以及50年内超越概率为14%的等加速度区划图。 相似文献
175.
东北地区地震危险趋势分析 总被引:2,自引:3,他引:2
利用丰富的震史资料,研究了日本海沟、日本海深震与中国东北浅震的时空特征。根据深震、浅震的相关活动特点,我们对东北浅震危险趋势进行了分析。 相似文献
176.
华北北部地区年前地震危险性预测研究组 《地震》1995,(4):391-395
综述了利用确定性和概率性相结合的预测方法,对华北北部地区2005年前的地震危险性进行了概率预测研究。研究表明,该区在200年前发生6级以上地震的概率为0.45,其中涿鹿-怀来一带地区内每个计算单元中的发展概率最高,达到0.02。 相似文献
177.
We examined patterns of co-existence for three species of scincid lizards (Sphenops sepsoides, Scincus scincus, and Chalcides ocellatus) in the simple sand dune habitat of North Sinai, Egypt. We first examined the morphological differences among the three species and compared their niche use and escape tactics in the context of their morphologies. Our results suggests that natural selection has favored two different phenotypes, Scincus scincus's long limbs with toe fringes and Sphenops sepspoides's extremely reduced limbs for sand locomotion. These two sand specialists, Sphenops sepsoides and Scincus scincus, shared microhabitats such as soft substrate and occurred further away from vegetation but showed strong separation in the surface temperatures at which they were active. The generalist species, C. ocellatus which lacked toe fringes and had relatively short limbs that were not reduced enough for fossorial movement, was found closer to vegetation and on harder substrates where such traits may be beneficial. Escape tactics may further strengthen habitat partitioning between desert generalists and sand specialists as C. ocellatus sprint to vegetation to escape predators whereas both sand specialists dive into the sand. Our results suggest that traditional ideas about predation risk may not apply to sand diving lizards as they may be able to venture far from vegetation refuges without increased vulnerability to predation. 相似文献
178.
Urban Seismic Risk Evaluation: A Holistic Approach 总被引:3,自引:4,他引:3
Risk has been defined, for management purposes, as the potential economic, social and environmental consequences of hazardous
events that may occur in a specified period of time. However, in the past, the concept of risk has been defined in a fragmentary
way in many cases, according to each scientific discipline involved in its appraisal. From the perspective of this article,
risk requires a multidisciplinary evaluation that takes into account not only the expected physical damage, the number and
type of casualties or economic losses, but also the conditions related to social fragility and lack of resilience conditions,
which favour the second order effects (indirect effects) when a hazard event strikes an urban centre. The proposed general
method of urban risk evaluation is multi hazard and holistic, that is, an integrated and comprehensive approach to guide decision-making.
The evaluation of the potential physical damage (hard approach) as the result of the convolution of hazard and physical vulnerability
of buildings and infrastructure is the first step of this method. Subsequently, a set of social context conditions that aggravate
the physical effects are also considered (soft approach). In the method here proposed, the holistic risk evaluation is based
on urban risk indicators. According to this procedure, a physical risk index is obtained, for each unit of analysis, from
existing loss scenarios, whereas the total risk index is obtained by factoring the former index by an impact factor or aggravating
coefficient, based on variables associated with the socio-economic conditions of each unit of analysis. Finally, the proposed
method is applied in its single hazard form to the holistic seismic risk evaluation for the cities of Bogota (Colombia) and
Barcelona (Spain). 相似文献
179.
Research shows that flood damage potential has increased significantly in the last 15 years. At the same time, flood policy has shifted away from simplistic flood defence towards 'living with floods' and 'making space for water'. This paper explores the mis-match between the aspiration in policy ideals, the reality of rising potential economic damages and the inability of the flood risk appraisal process to match the aspiration with the reality. Unless investment appraisal procedures are changed, the increase in damages will undermine policy changes that seek a different pattern of flood risk management, away from economically dominated decision-criteria towards more sustainable objectives. 相似文献
180.
The evolving role of voluntarism in ageing rural communities 总被引:1,自引:0,他引:1