UNCERTAINTY OF EXTREME FLOOD ESTIMATES INCORPRATING HISTORICAL DATA1

ABSTRACT: The ability to predict extreme floods is an important part of the planning process for any water project for which failure will be very costly. The length of a gage record available for use in estimating extreme flows is generally much shorter than the recurrence interval of the desired flows, resulting in estimates having a high degree of uncertainty. Maximum likelihood estimators of the parameters of the three parameter lognormal (3PLN) distribution, which make use of historical data, are presented. A Monte Carlo study of extreme flows estimated from samples drawn from three hypothetical 3PLN populations showed that inclusion of historical flows with the gage record reduced the bias and variance of extreme flow estimates. Asymptotic theory approximations of parameter variances and covariances calculated using the second and mixed partial derivatives of the log likelihood function agreed well with Monte Carlo results. First order approximations of the standard deviations of the extreme flow estimates did not agree with the Monte Carlo results. An alternative method for calculating those standard deviations, the “asymptotic simulation” method, is described. The standard deviations calculated by asymptotic simulation agree well with the Monte Carlo results.     

常州地区村镇自建住宅抗震设防措施与对策研究

针对江苏省常州市地区村镇自建住宅的抗震性能进行了调查研究,针对存在的问题提出了相应的抗震设防措施与对策.     

环境哲学与历史性转变

所谓环境哲学，就是从哲学角度研究环境与发展这一矛盾的运动规律，并用以指导环境工作实践的一门科学。从哲学角度看，推行历史性转变首在转变那些不适应客观变化的观念、经验和制度，以实践作为检验真理的唯一标准，对受计划经济体制影响的理念和经验进行反思，走出误区，以利转变。环境与经济的“并重”和“同步”是促进环境与发展矛盾转化的根本途径，“综合”是用改革的方法解决发展中的环境问题，是实现前两个转变的基本保障。总之，实施“三个转变”就是发挥人的主观能动作用，积极创造条件，促使环境与发展的矛盾由“两难”向“双赢”转化，将“以牺牲环境换取经济增长”转变为“以保护环境，优化经济增长”，真正走上生产发展、生活富裕、生态良好的文明发展道路。     

A PROPOSED METHOD OF EVALUATING FLOOD DAMAGES TO HISTORIC HOMES - AN EXTERNALITY APPROACH1

ABSTRACT: Traditional procedures for evaluating flood damages to residential dwellings do not reflect intrinsic values when applied to historic homes. Such structures are worth more than that determined by using depth-damage curves provided by insurance companies who assess damage values based upon current labor and material costs. The evaluation of the worth of a historic home and subsequent damages due to inundation can be regarded as a problem of externalities. An assessment technique reflecting historic amenities or what has been termed replication cost is proposed in this paper. Replication costs would have widespread use not only in solving flood dammage problems, but also in any study where historic entities are subject to damages from catastrophies such as hurricanes, soil and beach erosion, and increasing urbanization. If adopted as a technique, it would enhance and preserve the ever-decreasing enclaves of historic homes and neighborhoods.     

Changes in housing in Guatemala following the 1976 earthquake: With special reference to earthen structures and how they are perceived by disaster victims*

This paper reports on what has happened to earthen structures in 26 Guatemalan communities studied over a 4-year period since the 1976 earthquake. The data were obtained from three waves of personal interviews with 1472 randomly sampled household heads. The results show that adobe, which was the primary housing material before the earthquake was heavily damaged in that event. As a consequence the number of adobe structures and of other earthen structures has been drastically reduced. The people of Guatemala individually and because of agency housing programs have abandoned adobe as a building material and turned to concrete block and wood. Surviving earthen structures have not been improved substantially and remain with largely the same structural features as before the earthquake. The greatest improvement is in the use of comer posts or columns in the walls but most of these are made of untreated crude logs or lumber, subject to rot and termite damage. Little information on aseismic housing seems to have spread either within the earthquake area or in the unaffected areas surrounding it. A program to spread information on how to use adobe in aseismic designs needs to be conducted along with one to assist citizens to aquire the resources necessary to improve the earthquake vulnerability of houses.     

华东地区地震目录的完全性分析

按照文献 [1]提出的分析方法 ,对华东地区地震发生率进行了统计修补 ,由此得到华东地区地震发生的概率密度分布。其结果对地震活动性研究和地震危险区的划分具有一定意义。在地震目录分段分析研究中 ,引入了Fisher的时序分割法     

应用极值理论研究台湾和华东地区中强地震活动的相关性

运用极值分布理论对1970～1999年间台湾和华东地区的地震资料进行统计性研究,得出其地震相应震级的复发周期[T(M)]、理论发震次数(η)和华东地区中强地震的发震概率阈值(PO)。通过对T(M)的同比分析,发现两地中强地震存在着较好的相关性。用以上研究的结果对华东地区5级以上地震的发震概率、发震时间和地震强度进行综合判定,效果较好。     

历史街区旅游开发初探

在阐释历史街区内涵的基础上，研究了历史街区旅游开发的问题。通过分析历史街区旅游开发的必要性及可能带来的负面影响，依据历史街区的保护原则，借鉴国内外历史古城旅游利用的基本思路，提出了历史街区旅游开发的“主客相融”模式和“低密高质”模式。     

河淮地震带地震活动特征

通过对河淮地震带历史地震和现今地震活动特征的研究 ,初步认为研究区地震活动存在准周期性变化。研究还发现 ,该区地震活动与中国大陆地震活动存在一定的相关性。