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61.
In this part of our study the probabilistic seismic hazard analysis (PSHA) for Tulbagh was performed. The applied procedure is parametric and consists essentially of two steps. The first step is applicable to the area in the vicinity of Tulbagh and requires an estimation of the area-specific parameters, which, in this case, is the mean seismic activity rate, , the Gutenberg-Richter parameter, b, and the maximum regional magnitude, mmax. The second step is applicable to the Tulbagh site, and consists of parameters of distribution of amplitude of the selected ground motion parameter. The current application of the procedure provides an assessment of the PSHA in terms of peak ground acceleration (PGA) and spectral acceleration (SA). The procedure permits the combination of both historical and instrumental data. The historical part of the catalogue only contains the strongest events, whereas the complete part can be divided into several subcatalogues, each assumed complete above a specified threshold of magnitude. In the analysis, the uncertainty in the determination of the earthquake was taken into account by incorporation of the concept of `apparent magnitude'. The PSHA technique has been developed specifically for the estimation of seismic hazard at individual sites without the subjective judgement involved in the definition of seismic source zones, when the specific active faults have not been mapped or identified, and where the causes of seismicity are not well understood. The results of the hazard assessment are expressed as probabilities that specified values of PGA will be exceeded during the chosen time intervals, and similarly for the spectral accelerations. A worst case scenario sketches the possibility of a maximum PGA of 0.30g. The results of the hazard assessment can be used as input to a seismic risk assessment. 相似文献
62.
为国土整理工作提供的测绘保障,称之为“国土整理测量”,它主要由“面”的规划调查测量和“点”、“线”的实施工程测量组成。权属调查、行政区划调查是国土整理测量工作的重要组成部分,在某些情况下,还须进行人口与水资源调查。国土整理测量必须建立土地台帐,并达到综合利用土地台帐的目的。日本等经济发达国家在20纪50年代即巳开展了长期化、制度化的国土整理工作,而我国则刚刚起步,因此尚存在没有统一的技术标准、总体规划性不强、缺乏前瞻性和国土整理测量成果没有得到综合利用等问题。所以:依据我国国情,借鉴国外经验,探讨国土整理测量的特点、作业流程及实施方法,为即将到来的大规模国土整理测量提供必要的理论依据与技术标准、实施方法与手段,具有很强的必要性与迫切性。 相似文献
63.
Archaeoseismic research contributes important data on past earthquakes. A limitation of the usefulness of archaeoseismology is due to the lack of continuous discussion about the methodology. The methodological issues are particularly important because archaeoseismological investigations of past earthquakes make use of a large variety of methods. Typical in situ investigations include: (1) reconstruction of the local archaeological stratigraphy aimed at defining the correct position and chronology of a destruction layer, presumably related to an earthquake; (2) analysis of the deformations potentially due to seismic shaking or secondary earthquake effects, detectable on walls; (3) analysis of the depositional characteristics of the collapsed material; (4) investigations of the local geology and geomorphology to define possible natural cause(s) of the destruction; (5) investigations of the local factors affecting the ground motion amplifications; and (6) estimation of the dynamic excitation, which affected the site under investigation. Subsequently, a ‘territorial’ approach testing evidence of synchronous destruction in a certain region may delineate the extent of the area struck by the earthquake. The most reliable results of an archaeoseismological investigation are obtained by application of modern geoarchaeological practice (archaeological stratigraphy plus geological–geomorphological data), with the addition of a geophysical-engineering quantitative approach and (if available) historical information. This gives a basic dataset necessary to perform quantitative analyses which, in turn, corroborate the archaeoseismic hypothesis. Since archaeoseismological investigations can reveal the possible natural causes of destruction at a site, they contribute to the wider field of environmental archaeology, that seeks to define the history of the relationship between humans and the environment. Finally, through the improvement of the knowledge on the past seismicity, these studies can contribute to the regional estimation of seismic hazard. 相似文献
64.
通过对工资明细汇总表中各项目归类,完成工资各“目”“节”科目帐务处理,实现工资记帐明细表和工资记帐凭单的查询和打印等功能。 相似文献
65.
MICHAEL WILLIAMS 《Geographical review》1998,88(2):275-300
ABSTRACT. The first half of the twentieth century marked both an end to confidence in human control of the earth and a prelude to the contemporary era of intense environmental concern after 1950. This conspectus of the environmental history/historical geography of the transitional years between 1900 and 1950 focuses on rising concerns over resource supplies and exploitation, particularly land settlement, timber supplies, soil erosion, and river-basin control. Conservation and the pervasiveness of ecological thinking and analogy form a strong underlying theme. 相似文献
66.
Numerical Simulation of the 1918 Puerto Rico Tsunami 总被引:1,自引:0,他引:1
The Caribbean Sea region is well known for its hurricanes, and less known for tsunamis. As part of its responsibilities in hazard assessment and mitigation, the U.S.A. Federal Emergency Management Agency, and the Puerto Rico Civil Defense, funded a pilot study to perform a numerical simulation of the 1918 Puerto Rico tsunami, one of the most deadly in the region. As part of the study a review has been made of the tectonic and tsunamigenic environment around Puerto Rico, the fault parameters for the 1918 event have been estimated, and a numerical simulation has been done using a tsunami propagation and runup model obtained through the Tsunami Inundation Modeling for Exchange (TIME) program. Model results have been compared with the observed runup values all along the west coast of Puerto Rico. 相似文献
67.
地史重大转折期的环境变化学术讨论会综述 总被引:7,自引:0,他引:7
概述了地史重大转折期的环境变化学术讨论会4个方面的主要科学内容:古生代与中生代之交的全球环境变化,泥贫纪弗拉期与法门期之交的全球环境变化,元古宙与显生宙之交扔全球环境变化和地史重大转折期环境变化的研究方法。围绕上述内容,评述了发言人和专题发言人的主要科学资料和科学思想以及本次会议形成的共识。 相似文献
68.
TherelationshipbetwentheearthquakesofNingboareaandtheNeotectonicmovementJIAGENGCHEN1)(陈家庚)CUNGUOCHEN2)(陈存国)LIWANG2)(王里)BO... 相似文献
69.
用历史类比法对中国强震活动的概率预测 总被引:1,自引:0,他引:1
本文将20世纪全球强震活动划分为7个活动期,以国内中强以上地震同期活动资料进行比较,对未来国内强震活动趋势作出中期的统计概率预测,似乎可以作为一个较为有力的判据。 相似文献
70.