应用ΣE2/3-t曲线进行中期地震预报的研究

本文分析了我国１９００年以来Ｍｓ≥７．０级地震前与断层面总面积有关的参量ΣＥ＾２／３随时间的变化，探讨了运用ΣＥ＾２／３－ｔ曲线进行中期地震预报的可能性。通过分析某一地区历史地震的Ｅ＾２／３（ｔ）曲线，可以认识这一地区在过去若干年内地震的活动情况，并由此判断该区未来几年到几十年内地震活动的总状态；还可以根据Ｅ＾２／３（ｔ）曲线外推估计一个地区目前地需求的可能强度。本文对Ｅ＾２／３（ｔ）曲线的基本形     

多年冻土区短桩架空通风基础房屋的模型试验研究

本介绍了工程建筑物基础和多年冻土地基整体的相似模型试验，试验结果与实体取得良好的一致。从动态过程肯定了持力层为含土冰层时，冻土允许承载力Ｒｆ的可靠性，同时，明确了可依据冻土层年平均地温Ｔｃｐ＝－２．５℃时，持力层（平均）地温Ｔ＝－０．５℃，允许承载力Ｒｆ＝０．１ＭＰａ，只能建一层平房，当Ｔｃｐ＝－４．０℃时，Ｔ＝－１．０－１．２℃，Ｒｆ＝０．１５－０．１７ＭＰａ，可有条件地建二层楼房。     

How to improve attribution of changes in drought and flood impacts

ABSTRACT

For the development of sustainable, efficient risk management strategies for the hydrological extremes of droughts and floods, it is essential to understand the temporal changes of impacts, and their respective causes and interactions. In particular, little is known about changes in vulnerability and their influence on drought and flood impacts. We present a fictitious dialogue between two experts, one in droughts and the other in floods, showing that the main obstacles to scientific advancement in this area are both a lack of data and a lack of commonly accepted approaches. The drought and flood experts “discuss” available data and methods and we suggest a complementary approach. This approach consists of collecting a large number of single or multiple paired-event case studies from catchments around the world, undertaking detailed analyses of changes in impacts and drivers, and carrying out a comparative analysis. The advantages of this approach are that it allows detailed context- and location-specific assessments based on the paired-event analyses, and reveals general, transferable conclusions based on the comparative analysis of various case studies. Additionally, it is quite flexible in terms of data and can accommodate differences between floods and droughts.     

Exploring changes in hydrogeological risk awareness and preparedness over time: a case study in northeastern Italy

ABSTRACT

Hydrogeological hazards are increasingly causing damage worldwide due to climatic and socio-economic changes. Building resilient communities is crucial to reduce potential losses. To this end, one of the first steps is to understand how people perceive potential threats around them. This study aims at exploring how risk awareness of, and preparedness to, face hydrological hazards changes over time. A cohort study was carried out in two villages in the northeastern Italian Alps, Romagnano and Vermiglio, affected by debris flows in 2000 and 2002. Surveys were conducted in 2005 and 2018, and the results compared. The survey data show that both awareness and preparedness decreased over time. We attribute this change to the fact that no event had occurred in a long time and to a lack of proper risk communication strategies. The outcomes of this study contribute to socio-hydrological modelling by providing empirical data on human behaviour dynamics.     

Structural,dynamic and anthropic conditions that trigger the emergence of the levee effect: insight from a simplified risk-based framework

ABSTRACT

Levees are the most common structural solution to prevent flooding, reduce damage and generate benefits through more investment/economic activity in floodplain areas. While being relatively easy to build, levee effectiveness can be compromised by poor design and substandard construction methods and maintenance, thus increasing failure probability. Further, levees might increase societal vulnerability by instilling a sense of safety, the so-called “levee effect”. To cope with these phenomena, we develop a risk-based framework that quantifies residual risk under levee breaching and the levee effect, by disentangling its structural, dynamic and anthropic components, thus contributing to a better understanding of the phenomena at different spatial scales and the definition of flood risk policies. Through an illustrative example, we show how residual risk might become larger than under natural conditions, as function of the scale of interest, e.g. an area, a line at a given distance from the river, or a point within the floodplain.     

Assessing parameter identifiability for multiple performance criteria to constrain model parameters

ABSTRACT

Reliable simulations of hydrological models require that model parameters are precisely identified. In constraining model parameters to small ranges, high parameter identifiability is achieved. In this study, it is investigated how precisely model parameters can be constrained in relation to a set of contrasting performance criteria. For this, model simulations with identical parameter samplings are carried out with a hydrological model (SWAT) applied to three contrasting catchments in Germany (lowland, mid-range mountains, alpine regions). Ten performance criteria including statistical metrics and signature measures are calculated for each model simulation. Based on the parameter identifiability that is computed separately for each performance criterion, model parameters are constrained to smaller ranges individually for each catchment. An iterative repetition of model simulations with successively constrained parameter ranges leads to more precise parameter identifiability and improves model performance. Based on these results, a more consistent handling of model parameters is achieved for model calibration.     

Using historical source data to understand urban flood risk: a socio-hydrological modelling application at Gregório Creek,Brazil

ABSTRACT

The city of São Carlos, state of São Paulo, Brazil, has a historical coexistence between society and floods. Unplanned urbanization in this area is a representative feature of how Brazilian cities have developed, undermining the impact of natural hazards. The Gregório Creek catchment is an enigma of complex dynamics concerning the relationship between humans and water in Brazilian cities. Our hypothesis is that social memory of floods can improve future resilience. In this paper we analyse flood risk dynamics in a small urban catchment, identify the impacts of social memory on building resilience and propose measures to reduce the risk of floods. We applied a socio-hydrological model using data collected from newspapers from 1940 to 2018. The model was able to elucidate human–water processes in the catchment and the historical source data proved to be a useful tool to fill gaps in the data in small urban basins.     

湿度偏低对2016年上海奉贤黄桃开花坐果的影响及致灾风险

利用2009—2018年奉贤黄桃休眠—花期各物候期、同期气象要素及1980—2018年黄桃花期逐日日平均、日最小相对湿度等资料，用对比及数理统计方法对2016年影响黄桃开花坐果的主要气象致灾因子、39年花期相对湿度变化特征及其影响进行分析。结果表明：2016年黄桃开花始期—开花盛期遭遇持续6 d日最小相对湿度小于等于30%的低湿天气，每天09：00—20：00各整点相对湿度的平均值小于等于50%，导致当年坐果大幅偏少。20世纪80年代以来，黄桃花期平均相对湿度、平均最小相对湿度均呈下降趋势，两者突变年份均为2000年，且3月下旬及4月上旬低湿天气出现概率高，提升了黄桃花期遭遇低湿致灾的风险。2009—2018年开花始期与5 d滑动平均气温大于等于10 ℃首日（简称10 ℃首日）呈显著性正相关。建立基于10 ℃首日的黄桃开花始期最小二乘偏回归方程,拟合效果较好,为协同应对低湿天气提供预测服务。     

地震危险区的边界划分探讨

本文针对目前地震危险区边界划分上存在的问题,从地震地质和地震构造的角度,结合测震学方法进行了分析,指出地震分布和地震危险区边界划定与活动构造有密切的联系。依据这一思想,阐明了构造活动与地震活动的关系,初步提出了地震危险区边界判析的原则,即把地震危险区限制在一定的地震构造区(带);其边界依据活动构造划定;在地震危险区内部进行发震构造条件研究,并对这些发震构造(活断层)进行活动度分析;分层次地对地震危险区范围及其危险度进行确定。 本文着重进行了活动构造的研究,对中国大陆的活断层、新生代盆地、地形面以及古地震等作了活动时代、活动性质、活动强度等多方面的论述。     

古地磁数据可靠性的试用判据

古地磁数据的可靠性问题,迄今已成为古地磁学进一步发展的关键所在。早在1964年Irving首次提出了数据可靠性的最低判据。当时绝大部分数据为天然剩磁测试结果（至1963年所搜集的554个数据中,经磁清洗的仅占12％）,因此,该判据强调一致性及野外检验。随着磁清洗技术的不断完善和广泛应用(1964-1970年新增的812个数据