Resistance to relocation in flood-vulnerable coastal areas: a proposed composite index     

Hélène Rey-Valette  Samuel Robert 《Climate Policy》2019,19(2):206-218

The increasing number of coastal floods in recent years in France has resulted in the design of new adaptation principles for the most endangered coastal areas. The aim of the government is to reduce the vulnerability of these areas by relocating property and infrastructure. These measures have, however, come up against considerable opposition from the population concerned. Using a survey of 421 inhabitants of Hyères, a coastal town in the South of France, this article proposes the study of resistance to relocation through the creation of an index for resistance that incorporates attachment to place, residential mobility and risk perception. The results show a correlation for the index and distance from the sea that highlights the existence of conflicting interests with adaptation measures depending upon population categories.

Key policy insights

• In France, although coastal flooding risk is a key issue in numerous populated coastal areas, coastal dwellers show little willingness to relocate.

• Resistance to relocation can be assessed through a composite index integrating place attachment, residential mobility and risk perception.

• Application of such an index shows a correlation between willingness to relocate and distance from the sea.

• Conflicts of interest with adaptation measures also depend on the age of the dwellers, their standard of living and on home ownership.

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Seismic activities before and after the impoundment of the Xiangjiaba and Xiluodu reservoirs in the lower Jinsha River          下载免费PDF全文

Ce Zhao  Cuiping Zhao  Hongfu Lei  Mengdi Yao 《地震科学（英文版）》2022,35(5):355-370

The lower Jinsha River basin is located at the junction of Sichuan and Yunnan provinces in Southwest China, a region with intense tectonic movements and frequent moderate to strong seismic activities. Cascade hydropower stations have been constructed along the lower Jinsha River since 2012. However, research on the effect of the impoundment of large-scale cascade reservoirs in a river basin on local seismic activities is currently lacking. Accurately identifying earthquake locations is essential for studying reservoir-induced earthquakes. Analyzing the spatiotemporal migration process of seismic activities based on complete and precise earthquake relocation is fundamental for determining the fluid diffusion coefficient, constructing fault models for reservoir areas, identifying earthquake types, exploring earthquake mechanisms, and evaluating seismic hazards. The seismicity pattern in the Xiangjiaba and Xiluodu reservoir areas, where seismic activities had been weak for a long time, has changed with the successive impoundment of the two reservoirs, showing microseismic events and seismic clusters. We investigated the spatiotemporal characteristics of seismic activities in the Xiangjiaba and Xiluodu reservoir areas using the waveform cross-correlation-based double-difference relocation technique and the b-value analysis method. We discovered that seismic events after the impoundment of these two reservoirs exhibited different characteristics in different regions. The seismic activities at the Xiluodu dam quickly responded to the rising water level, with the seismic intensity decaying rapidly afterward. These events were concentrated in the limestone strata along both sides of the Jinsha River, with a shallow focal depth, generally within 5 km, and a high b-value of approximately 1.2. Such features are close to those of karst-type earthquakes. Microseismic activities frequent occur on the eastern bank of the Yongshan reservoir section downstream of the Xiluodu dam, with two parallel NW-trending earthquake strips visible after precise earthquake relocation. The M_S5.2 earthquake near Wuji town on August 17, 2014, had prominent foreshocks and aftershocks distributed in a clear NW-trending 20-km-long strip, perpendicular to the riverbank. These seismic events had a low b-value of approximately 0.7. The orientation of the node plane revealed by the strike-slip focal mechanism of the mainshock is consistent with that of the strip formed by the foreshock-mainshock-aftershock sequence, indicating the existence of a NW-striking concealed fault. Seismic activities near the Yanjin-Mabian fault upstream of the Xiangjiaba reservoir area since 2013 were concentrated in a NW-trending strip, with several near EW-trending seismic clusters on its western side, and with the largest event having a magnitude of M_L3.7. So far, the impoundment of the Xiangjiaba and Xiluodu reservoirs has not triggered seismic activities on the large Jinyang-Ebian and Yanjin-Mabian faults nearby.  相似文献   

唐山北部地区浅层一维剪切波速度结构初步研究     

王莉婵  毛国良  蔡玲玲  马旭东  王亚玲  王宁 《震灾防御技术》2022,17(1):104-113

2019年8月2日河北省唐山市路南区某矿井区发生M_L2.4巷道塌陷,基于塌陷周边台站观测到的短周期瑞雷波,提取面波基阶群速度频散曲线,并利用迭代反演方法得到研究区域地下10 km深度范围内的一维剪切波速度结构,用于精定位分析。速度分析结果表明,研究区域浅表剪切波速度约为2.46 km/s;深度为2 km时,塌陷周边存在小范围的低速区,速度约为2.57 km/s;深度约为4 km时,剪切波速度达3.47 km/s;深度为5～9 km时,唐山东部沉积盆地内存在1个剪切波低速层。精定位分析结果表明,增加浅层速度模型有助于提高深度较小的地震定位精度;塌陷周边的低速区向下延伸近20 km,为地震多发区。  相似文献   

Normal faulting mechanisms in the Western Desert of Egypt     

Ali K. Abdel-Fattah  Ahmed Badawy  K. Y. Kim 《Journal of Seismology》2007,11(1):27-38

Egypt is recognized as a moderate seismicity region where earthquakes are distributed within several active regions. Owing to sparse distribution of both seismicity and seismic stations, mostly moderate-size Egyptian earthquakes were recorded by regional stations. One of such cases is the moderate-size earthquakes of moment magnitudes greater than 4.0 which struck the Western Desert of Egypt in 1998 and 1999. These events are the first instrumentally recorded earthquakes occurring in the area. In the present study, the source mechanism for these earthquakes was estimated using the waveform data recorded from one of the very broadband MedNet seismograph stations and polarities from the national short-period seismographs. An iterative technique was applied to find the best-fit double-couple mechanism by a grid search over strike, dip and rake. Regional synthetic seismograms were calculated by using f–k integration in the frequency range of 0.03–0.1 Hz. A crustal structure fitted to surface wave dispersion curves was used to compute Green’s function. Focal depths were determined through the grid search method for a range of source depths. Our results show a normal faulting mechanism with minor strike-slip component. The NNW trend has been chosen as a preferred rupture plane in consistence with surface and subsurface faults and microearthquake seismicity in the epicenteral area as well.  相似文献   

地球表面时空多变要素的定量遥感项目综述   总被引：6，自引：1，他引：6  

李小文 《地球科学进展》2006,21(8):771-780

对“973”项目“地球表面时空多变要素的定量遥感理论及应用”的研究工作做了综述，介绍了项目研究的科学背景、总体科学思路、研究内容和科学目标。项目经过5年的努力，在尺度效应和尺度转换理论、基于先验知识的定量遥感反演理论、同步观测和模拟试验等方面取得了一系列研究成果；成功实现了遥感模型与农学、生态学等应用模型的链接，并在精准农业、西北草场生态建设中进行了成功应用。  相似文献   

Accurate relocation of earthquakes in central-western China using the double-difference earthquake location algorithm   总被引：3，自引：0，他引：3  

杨智娴  陈运泰  郑月军  于湘伟 《中国科学D辑(英文版)》2003,46(Z2)

The double-difference earthquake relocation algorithm (DD algorithm) has been applied to the accurate relocation of 10057 earthquakes in the central-western China (21°-36°N, 98°-112E°) during the period of 1992-1999. In total, 79706 readings for P waves and 72169 readings for S waves were used in the relocation, and the source parameters of 6496 events were obtained. The relocation results revealed a more complete picture of the hypocentral distribution in the central-western China. In several seismic belts the relocated epicenters present a more defined lineation feature, reflecting the close correlation between the seismicity and the active tectonic structures. The relocated focal depths confirmed that most earthquakes (91 percent of the 6496 relocated events) in the central-western China were located at shallower depths not deeper than 20 km. The distribution of focal depths indicates that the seismogenic layer in the central-western China is located in the upper-mid crust with its thickness no deeper than 20 km.  相似文献   

Hypocenter migration of fluid-induced earthquake swarms in the Tjörnes Fracture Zone (North Iceland)     

Martin Hensch  Carsten Riedel  Jrg Reinhardt  Torsten Dahm  The NICE-People 《Tectonophysics》2008,447(1-4):80

The Tjörnes Fracture Zone separates Iceland's North Volcanic Zone from Kolbeinsey-Ridge (Greenland-Sea). Seismicity mainly occurs in swarms, often 100 and more per day, with similar waveforms and frequently offshore.We analysed three earthquake swarms between June and September 2004, recorded by 35 stations, i.e. the permanent Icelandic SIL network and a temporary setup of land and ocean-bottom-seismometers, and 5 swarms of the years 1994-1997 only using the sparser SIL network. Events occurring in the same swarm often show similar waveforms at the same station. We cross-correlated these time series by using a new approach of three component cross-correlation in order to relocate the hypocenters relative within the swarms and to precisely determine the direction and velocity of migration. Our method delivered good relocations with small spatial and temporal errors. This allows the interpretation and characterisation of the observed earthquake swarms. We try to classify observed migration velocities by comparing them to typical fluid- and crack-propagation velocities and determine focal-mechanisms and orientation of the best fitting plane through the hypocenter distribution.We separate the investigated events into two types of earthquake swarms, supposedly dike-induced and hydrothermally- or gas-induced swarms, by pointing out typical characteristics of both types and by comparing them to similar events of other volcanic regions. Based on different migration velocities, we will discuss possible mechanisms and their triggers of all single clusters within a swarm. Hypothetic models will be established, trying to explain the processes during the swarm episodes and to derive possible pre-eruptive patterns from the character of seismicity.  相似文献   

京津冀地区制造业集聚的时空演化特征和差异性分析     

黄宇金  孙威 《地理科学进展》2021,40(12):2011-2024

2015年国家提出京津冀协同发展战略,产业协同是推进这一战略的先行领域,因此产业在该地区的集聚与分散受到学界的广泛关注。论文利用全国3次经济普查数据,基于企业的空间位置信息,运用DO指数方法研究了京津冀地区制造业集聚的时空演化特征并对比分析了集聚特征在区域、行业、企业间的差异性。研究表明： ① 2004—2013年京津冀地区制造业集聚的比例从69.0%提高到82.8%,集聚多发生在0~50 km的范围。随着集聚范围逐渐扩大,集聚强度逐渐减弱,下降幅度达到25.9%。② 在区域层面,集聚更容易发生在北京、天津2个直辖市;在行业层面,集聚更容易发生在技术密集型和劳动密集型的制造业且集聚范围更短;在企业层面,集聚更容易发生在小企业。③ 2004—2013年京津冀地区已经出现了制造业从北京、天津向河北扩散的趋势,特别是一些技术水平较低、劳动力需求较大的制造业,表明在2015年提出京津冀协同发展战略是适宜的。  相似文献   

Study of traditional rural settlements landscape genetic variability in shaanxi province based on accurate-restoration北大核心CSCDCSSCI     

Xiang Y.  Cao M.  Qin J.  Wu C. 《地理科学进展》2021,(9):1544-1556

Landscape genes of traditional rural settlements are a hotspot of settlements' landscape research. Based on existing research, this study defined the landscape genetic information chain and its hierarchy. The general life-like variation mechanism of landscape genes in traditional rural settlements was also proposed. On these bases, considering the landscape characteristics of traditional rural settlements in Shaanxi Province, the landscape genetic information chains of traditional rural settlements in the province were constructed and the general variation mechanism and characteristics of traditional rural settlements in the province were proposed. A theoretical framework of accurate restoration of the traditional rural settlements' landscape genetic information chain was further put forward. In addition, accurate restoration was applied to the typical settlement with variation in Shaanxi Province as an empirical case. The results verified the necessity and operability of accurate restoration. This research provides some thoughts and methods that are fresh and original for the protection and activation of traditional rural settlements from a landscape genetic perspective. © 2020, Editorial office of PROGRESS IN GEOGRAPHY. All rights reserved.  相似文献   

鲜水河断裂带南段深部变形的重复地震研究   总被引：4，自引：3，他引：1       下载免费PDF全文

李乐  陈棋福  钮凤林  苏金蓉 《地球物理学报》2015,58(11):4138-4148

利用2000—2013年四川数字地震台网和水库台网的波形资料以及川西流动台阵的事件波形,通过辨识发生在同一断层位置上的重复地震来定量研究鲜水河断裂带南段的深部变形.针对研究区台站分布稀疏的客观情况,应用了子采样条件下基于S-P相对到时差来约束震源位置一致性的方法,在鲜水河断裂带识别出11组重复地震,并利用连续波形资料进行了重复地震完整性的初步测试,同时运用结合波形互相关资料的双差法来完成研究区背景地震和重复地震位置的精确定位.重新定位后的地震图像展示研究区中上地壳存在明显缺震层,其与壳内的低速低阻层相吻合.利用重复地震的地震矩和重复间隔,估算出鲜水河断裂带南段孕震深部的滑动速率为3.0~10.2mm·a-1,显示研究区不同地震构造区的深部滑动速率存在明显差异.  相似文献