The May 2008 Sichuan,China earthquake: a herald of things to come.

The terrible disaster of the May 2008 Sichuan earthquake, which killed 70 000 people, is an example of a catastrophe that is likely to become more common in the future, particularly in Asia. Much of the population of Asia is now concentrated in poorly constructed cities that have grown very rapidly in places whose locations are closely related to their geological context, and specifically to the proximity of active earthquake‐generating faults. With the extreme vulnerability of many Asian megacities, a catastrophe even larger in scale now seems inevitable.     

水温突降-缓升型的响应机理之冷水下渗学说的研究——以重庆北温泉水Fe3+、Mn2+对汶川地震的响应为例

深井水温观测在中国已经开展了20多年,但目前对于水温响应机理的研究还不充分.而且利用温泉水对水温响应机理研究甚少.本文在2008年5月12日汶川8.0级地震前后,即2008年5月1日至7月4日,对重庆北温泉水(距震中约400 km)进行采样监测,发现泉水水温水量发生较大变化:震后水温下降了1℃:海拔相对较高的BWQ-2、BWQ-3、BWQ-4相继断流,监测点BWQ-1的水量增加了15 L/s;与此同时.各泉点Fe~(3+)、Mn~(2+)浓度于地震当日成倍增长,随后逐渐减小,7月4日时浓度与5月1日相当.重庆北温泉位于四川盆地东部边缘地带,受汶川地震强烈影响导致冷水下渗作用,海拔相对较高而温度较低的温泉水改道,并有其他来自裂隙或者地表的低温水汇入温泉含水层,Fe~(3+)、Mn~(2+)浓度的变化从水化学上印证了冷水下渗学说.     

重庆北温泉水化学特征对汶川8.0级地震的响应

2008年5月1日至7月4日汶川8.0级地震前后,对距震中约400 km的重庆北温泉7个泉点进行采样监测,发现其水温、水量及水化学特征均发生了较大变化：（1）所有泉点震后水温都下降了1℃左右;（2）海拔相对较高的BWQ-2、BWQ-3、BWQ-4泉点相继断流,而下游海拔较低的BWQ-1泉点水量则增加了15 L/s,BWQ-6泉点水量也有所增加;（3）海拔较低泉点泉水中K＋、Na＋、Ca2＋浓度减少,Mg2＋浓度增大,且K＋、Na＋、Ca2＋浓度呈正相关;Fe3＋、Mn2＋浓度于地震当日成倍增长,随后逐渐减小,7月4日时浓度与5月1日相当;SO42-、F-浓度增大后逐渐减少。引起北温泉水物理化学变化的主因是：由于汶川强烈地震,导致北温泉区上覆盖层裂隙与下伏温泉含水层裂隙贯通,地表或上覆盖层低温水汇入含水层所致。     

Trenching exposures of the surface rupture of 2008 Mw 7.9 Wenchuan earthquake,China: Implications for coseismic deformation and paleoseismology along the Central Longmen Shan thrust fault

The May 12, 2008, Mw 7.9 Wenchuan earthquake was induced by failure of two of the major faults of the Longmen Shan thrust fault zone along the eastern margin of Tibet Plateau. Our study focused on trenches across the Yingxiu–Bichuan fault, the central fault in the Longmen Shan belt that has a coseismic surface break of more than 200 km long. Trenching excavation across the 2008 earthquake rupture on three representative sites reveals the styles and amounts of the deformation and paleoseismicity along the Longmen Shan fault. Styles of coseismic deformation along the 2008 earthquake rupture at these three sites represent three models of deformation along a thrust fault. Two of the three trench exposures reveal one pre-2008 earthquake event, which is coincident with the pre-existing scarps. Based on the observation of exposed stratigraphy and structures in the trenches and the geomorphic expressions on ground surface, we interpret the 2008 earthquake as a characteristic earthquake along this fault. The interval of reoccurrence of large earthquake events on the Central Longmen Shan fault (the Yingxiu–Beichuan fault) can be inferred to be about 11,000 years according to ¹⁴C and OSL dating. The amounts of the vertical displacement and shortening across the surface rupture during the 2008 earthquake are determined to be 1.0–2.8 m and 0.15–1.32 m, respectively. The shortening rate and uplift rate are then estimated to be 0.09–0.12 mm/yr and 0.18–0.2 mm/yr, respectively. It is indicated that the deformation is absorbed mainly not by shortening, but by uplift along the rupture during the 2008 earthquake.     

The elliptic stress thermal field prior to <Emphasis Type="Italic">M</Emphasis><Subscript>S</Subscript> 7.3 Yutian,and <Emphasis Type="Italic">M</Emphasis><Subscript>S</Subscript> 8.0 Wenchuan earthquakes in China in 2008

Some thermal infrared anomalies on the earth’s surface are omens of stronger earthquakes, and have a close relationship with the stress fields. Satellite-based remote sensing is an important means of monitoring and researching this phenomenon. The M _S 7.3 Yutian earthquake in Xinjiang on March 20, 2008 and the M _S 8.0 Wenchuan earthquake in Sichuan on May 12, 2008 both happened in the Qinghai–Tibet Plateau, China, with epicenters more than 2,000 km apart. The two events, however, were a production of an identical stress field in different developing phases. Prior to the M _S 7.3 Yutian earthquake, a large-scale abnormal temperature rise not only covered the epicenter of the forthcoming Yutian earthquake, but also arrived at the epicenter of the farther Wenchuan earthquake. The revolving elliptic stress thermal field reflecting earthquake gestation moved from the west to the east of the Wenchuan epicenter at the time of the Yutian event occurrence. The rotation of the calefactive ellipses and belts prior to the two strong events agreed with the stress field, the focal mechanism, and modality and mechanism property of the ruptures in the crustal surface induced by the events. It should be a reflection of the partial mantle uprush and rotation.     

汶川地震地质灾害调查成果与展望

2008年5.12汶川地震是新中国成立以来破坏性最强、诱发地质灾害最严重的一次特大地震。本文简要介绍了国土资源地质大调查计划项目“汶川地震地质灾害调查评价”的主要研究进展与成果:采用空天地一体化调查、地球物理探测、GPS位移监测、斜坡地震动测试及大型物理模拟等技术,调查和研究了汶川地震地质灾害发育特征和分布规律,揭示内外动力耦合作用下的地质灾害成灾机理,并开展了震后重建区高位滑坡泥石流防治和监测预警关键技术研究,为强震山区重大地质灾害监测预警和灾后重建提供了技术支撑。     

High density neighborhoods: Who enjoys them?

To date, research into the subjective aspects of high density has focused mainly on the negative consequences of overcrowding. This study, in contrast, outlines some of the positive aspects of high density in neighborhoods, exploring the physical–spatial environment of two neighborhoods in the city of Haifa, Israel. It was found that while the relatively high residential density was similar in both neighborhoods (40 housing units per acre), this was more positively evaluated in one neighborhood as compared to the other. This can be attributed to some specific environmental and planning features. In particular, where physical planning enabled the potential advantages of high density to be realized, this was positively perceived and evaluated by local residents. Such advantages mainly comprised accessibility to a variety of services, more frequent public transportation, and access to open spaces within walking distance. Particularly advantageous were the increased opportunities for social gathering. At the same time, however, high density did not foster social relationships on the neighborhood level. The study further identified the gender and age groups that benefited most from the high density. Thus, women evaluated high density more positively than men. Young families with children and senior citizens (over 65) were also more likely to benefit, and to evaluate the high density environment more positively than other social groups.     

强震条件下谢家店滑坡碎屑流发生机制试验研究

谢家店滑坡是5.12汶川大地震触发的较为典型的高速远程滑坡之一。通过滑坡岩体碎屑动荷载力学试验以及微结构特征分析,初步探讨了强震条件下滑坡碎屑流发生的动力学机制。结果表明:红色正长花岗岩的空隙和裂隙的发育程度均高于黑褐色砂岩;随着应变速率的增加,两种岩石的抗剪强度都有相应增加的趋势,且黑褐色砂岩的强度高于红色正长花岗岩;在加载速率持续增长的情况下,两种试样抗剪断强度拟合直线斜率相同,故强度增长速率相等;汶川地震使两种岩石均达到了其抗剪强度,所以岩体的剪切破坏是导致该滑坡发生的主要原因之一。     

2008年汶川地震(Ms8.0)非对称同震破碎带的确定:来自WFSD-1随钻流体的证据

地震过程中相当可观的一部分能量消耗于裂隙的活化与形成,来自汶川地震断裂带科学钻探一号孔(WFSD-1)的随钻流体表明,地震新形成的裂隙对应有较强的流体异常,它们为流体的入侵提供了良好的通道。随钻流体呈非对称性分布于主滑移面的两侧,主要的流体异常带集中在主滑移带下方须家河组顶部120 m范围内,该带中气体的含量以及变动的频率明显高于上部相同的宽度范围以及下部沉积岩层,来自地球物理测井的资料同样显示这一带破碎严重并伴随有大量水的侵入,暗示汶川地震形成的裂隙具有非对称性分布的特征。这一特征可能同时受控于断裂上盘彭灌杂岩与下盘须家河组岩层的力学性质差异以及地震破裂过程中形成的非对称性应力分布。     

青海玛多“5·22”MS7.4级地震的同震地表破裂特征、成因及意义

2021年5月22日2时4分在青海省果洛藏族州玛多县境内发生M_S7.4级地震,此次玛多M_S7.4级地震是2008年汶川M_S8.0级大地震之后中国震级最大的一次地震,及时查明其同震地表破裂展布及特征,对于正确认识发震构造和区域防震减灾具有重要意义。根据震后现场调查,结合高分辨率卫星遥感图像的解译分析、余震数据和典型地震地表破裂的无人机低空摄影测量等结果,初步获得了此次地震6处典型地震地表破裂的特征。结果发现:此次玛多地震的地表破裂主要沿已知的东昆仑断裂带的南侧分支断裂昆仑山口-江错断裂的东南段分布,分析表明其中的江错断裂应是此次地震的发震断层;同震破裂的西段总体走向275°~300°,主要表现为挤压鼓包和雁列式张裂隙的斜列组合,其中江错贡麻段至江多村段出现了明显的1.4~0.8 m的垂直位移,指示该段可能具有较明显的正断层成分;中部黄河乡段主要由一系列呈左阶斜列的北西向P剪切裂缝和右阶雁行排列的北东向张裂隙构成,走滑位移较小;而东段地表破裂出现了多个分支,其中北支昌马河段主要由一系列雁行排列的张裂隙组成,总体走向为260°,与断裂西段的走向明显不同;地震造成的最大左旋位移出现在西段的错尔加拉破裂段,约2.8 m,指示此次地震地表破裂带的走滑位移主要呈从西向东的单侧扩展-衰减特征。考虑到此次玛多地震出现在东昆仑主干断裂南侧的巴颜喀拉地块内部,表明该地块内部具有发生7级以上大地震的能力,因此,巴颜喀拉地块内部强震活动的孕震条件和机理应该是未来需要进一步关注的科学问题。      

Salt-dissolution-induced subsidence in the Dead Sea area detected by applying interferometric techniques to ALOS Palsar Synthetic Aperture Radar images

This paper discusses the interpretation of ground motions detected in the dried up Lynch Strait, Dead Sea area, by applying radar interferometric techniques to ALOS Palsar Synthetic Aperture Radar images. Four ALOS scenes spanning from December 15, 2007 to May 17, 2008 have been processed leading to the generation of five interferograms. Three ground deformation zones have been detected. One of them shows surface displacement which could be related to an earthquake (ML 3.1) that took place on April 13, 2008. High rates of subsidence have been measured in the northern Lynch Strait. They suggest that these subsidence phenomena follow the same trend of rapid increase as sinkholes. Additional measurements should be carried out in order to refine this observation.

The comparison between sinkholes' distributions in the Lynch Strait with that of Ghor Al Haditha, six kilometers eastward, supports the idea that the earthquake that hit the southern Dead Sea on April 23, 1979 (M 5.1) reactivated faults and fractures in the Lynch Strait triggering the development of sinkholes and subsidence in the frame of the Dead Sea recession.     

中国地质科学院对5.12汶川地震的快速反应与调查研究

面对5.12汶川8级地震突发灾害,中国地质科学院组织专家,科学分析发震动力学背景,第一时间奔赴震中地区开展地表破裂变形与地震地质灾害调查,随后系统开展地震科学钻探选址、活动断裂与地震变形观测、地应力测量、地质灾害地面调查、堰塞湖与水工环综合评价。6位专家参加国家汶川地震专家委员会,编辑出版《汶川地震灾区地震—地质灾害图集》,组织召开汶川地震动力学分析研讨会,2位专家参加国土资源部抗震救灾前方指挥部工作。在第33届国际地质大会期间,组织汶川地震大型展览,应邀作汶川地震、地震科学钻、地表破裂等学术报告,受到国际同行的高度关注。组织申报汶川地震断裂带科学钻探工程,2008年11月第一口地震科学钻开工;组织落实国家专项、973课题、地质调查项目等科研任务,有效地调整了面向地质灾害的学科结构和人才布局。     

Abnormal Phenomena Recorded by Several Earthquake Precursor Observation Instruments Before the Ms 8.0 Wenchuan,Sichuan Earthquake

Abstract: The paper introduces the anomalies observed by digital tiltmeter, cross-fault deformation meter, 4-component borehole strainmeter and geothermometer before May 12, 2008, Ms8.0 Wenchuan earthquake, Sichuan. The digital tiltmeter installed in the epicentral region in Shifang County recorded the tilt anomalies 15 days before the earthquake with variation amplitude of 3.7 times larger than the annual deviation of 2007. The cross-fault deformation meter installed at Zimakua station on the Xianshuihe-Anninghe fault zone detected displacement anomaly occurring since 2006 with the variation amplitude exceeding the cumulative value of the last ten years. Five borehole strainmeter stations in the Chongqing section of Three Gorges Reservoir area observed unconventional strain changes occurring in the period from May 1 through 12, 2008. Among them, the strainmeter at Wanzhou station recorded the great compression strain rate on the EW component at 14:00 o'clock of May 10, and the anomaly amplitude was so large that the instrument output exceeded its dynamic range, corresponding to a level of ~104 nanostrains. The geothermometers installed in Xi’an, Chongqing and Xichang recorded the sudden temperature changes from November 2007 to January 2008 with the variation amplitudes several times larger than the ordinary deviation. The above phenomena and the criteria for distinguishing the anomalies from background fluctuations are discussed in this paper.     

Abnormal Phenomena Recorded by Several Earthquake Precursor Observation Instruments Before the Ms 8.0 Wenchuan, Sichuan Earthquake

The paper introduces the anomalies observed by digital tiltmeter, cross-fault deformation meter, 4-component borehole strainmeter and geothermometer before May 12, 2008, Ms8.0 Wenchuan earthquake, Sichuan. The digital tiltmeter installed in the epicentral region in Shifang County recorded the tilt anomalies 15 days before the earthquake with variation amplitude of 3.7 times larger than the annual deviation of 2007. The cross-fault deformation meter installed at Zimakua station on the Xianshuihe-Anninghe fault zone detected displacement anomaly occurring since 2006 with the variation amplitude exceeding the cumulative value of the last ten years. Five borehole strainmeter stations in the Chongqing section of Three Gorges Reservoir area observed unconventional strain changes occurring in the period from May 1 through 12, 2008. Among them, the strainmeter at Wanzhou station recorded the great compression strain rate on the EW component at 14:00 o'clock of May 10, and the anomaly amplitude was so large that the instrument output exceeded its dynamic range, corresponding to a level of ～104 nanostrains. The geothermometers installed in Xi'an, Chongqing and Xichang recorded the sudden temperature changes from November 2007 to January 2008 with the variation amplitudes several times larger than the ordinary deviation. The above phenomena and the criteria for distinguishing the anomalies from background fluctuations are discussed in this paper.     

Revisions of the M 8.0 Wenchuan earthquake seismic intensity map based on co-seismic landslide abundance

Natural Hazards - Hundreds of thousands of landslides were triggered by the May 12, 2008, Mw 7.9 Wenchuan earthquake in China. A detailed inventory of landslides triggered by the earthquake was...     

Secondary geological hazard analysis in Beichuan after the Wenchuan earthquake and recommendations for reconstruction

The Wenchuan earthquake, also known as 2008 Sichuan Earthquake, occurred along the Longmenshan fault zone on 12 May 2008 at 14:28:01.42 CST (06:28:01.42 UTC). It caused serious damage to structures in the region. Beichuan is a town which is within these severely damaged areas. According to the earthquake intensity distribution map of 2008 Wenchuan earthquake officially released by the China Earthquake Administration, the earthquake intensity in Beichuan was XI on the China seismic intensity scale. As the earthquake occurred in a mountainous area, there were thousands of landslides, rockfalls, debris flows, and surface ruptures triggered by the earthquake over a broad area. These secondary geological hazards substantially increased the human, social and economic impact of the earthquake. This paper presents a post-earthquake analysis on the secondary geological hazards in Beichuan. The risk analyses associated with construction of the National Earthquake Memorial Museum in Beichuan are assessed and recommendations on risk mitigations for the mass reconstruction over the ruins are also provided based on this field study.     

Ten years of landslide development after the Wenchuan earthquake: a case study from Miansi town,China

Natural Hazards - The earthquake outbreak on 12 May 2008, in Wenchuan County caused long-term instability and frequent geological hazards on the mountain slopes in the earthquake area. Considering...     

Gender and voluntary work in late adulthood in rural communities in the Netherlands

This article discusses the involvement of older women and men in voluntary work in rural communities in the Netherlands. Gender, ageing and civil society form the core concepts in the article. Politicians and policy makers in the Netherlands are worried about the perceived decline of civil society and about the consequences of this decline for specific categories of older women in terms of well-being and social exclusion. The paper presents the results of two surveys of involvement of older women and men in civic organisations, voluntary work and local actions. The surveys indicate high levels of involvement of both women and men. No gender differences are found in activity level. However, the data demonstrate the gendered nature of civil society. Women are more engaged in informal voluntary work and informal local actions, while men are more active in formal organisations and functions. This gender segmentation is not absolute, however. Many older women and men transgress the traditional feminine–masculine boundaries. The surveys highlight the involvement of women and men in rural communities, but indicate lower activity levels in urban areas.     

A study of the human-fatality rate in near-fault regions using the Victim Attribute Database

After the 1999 Chi-Chi earthquake, the Taiwanese government immediately issued new guidelines prohibiting the construction of structures for human occupancy within the Chelungpu fault zone. However, these guidelines were not based upon an in-depth hazard analysis of the near-fault regions. The positions of more than 80% of the 2,492 victims of the Chi-Chi earthquake were found by our research team. A Victim Attribute Database has been compiled that includes the GPS coordinates of the positioned victims as well as other attribute data associated with the victims. The human-fatality rates in the near-fault regions have been analyzed with regard to distances from the Chelungpu fault, the hanging-wall and footwall areas, as well as building type. The severity at the human-fatality rates in the near-fault regions is inversely proportional to distances from the causative fault, i.e., the closer the distance, the higher the human-fatality rate observed. The human-fatality rate for victims who lived in closer proximity to the hanging-wall areas is also significantly higher than those who lived in closer proximity to the footwall areas, especially in areas on either side of the fault and within 1,000 m of the fault surface trace. In terms of different building types, factors that include the capacity of the buildings to resistant strong shaking and the level of strong ground-motion greatly affected the human-fatality rates in the hanging-wall and footwall areas. Therefore simply prohibiting the construction of buildings within the active fault zone would be an insufficient method of reducing the number of potential victims; a nationwide effort should be undertaken to upgrade the capacity of buildings to resist strong shaking.     

The Roermond earthquake of 13 April 1992, the Netherlands: geological aspects

The epicentre of the Roermond earthquake is located near the western boundary fault of the Roer valley trough, one of the deepest and the most active in the Quaternary part of the Lower Rhine graben. The Late Pleistocene and Holocene activity of the trough is manifested by offsets of the main (Mindel) and the lower (Riss and Late Pleistocene) terraces along the boundary faults.
Surface fractures have been observed in an area of more than 50 km²: 2.5–3.5 km to the north of the town of Roermond, at 0.8 km to the south of the village of Herkenbosch and in the southeastern part of the village of Montfort. Three types of ruptures were differentiated: scarps up to 50 cm high along open fractures near the Maas River; open fractures (continued by scarps in some places) and open fractures with a liquefaction of the Quaternary alluvium sands. The last type is predominant. The location of the ruptures depends on the landscape and water-table of the region. While they could be produced solely by hydraulic shock during the earthquake (increased by the wet spring season), the majority of the ruptures strike N50°W ± 10°, i.e. parallel to the main trough faults, or N55°E ± 10°, along 'neotectonic lines', parallel to the Maas valley and deduced from space imagery. Thus, the ruptures could be the secondary surficial effect of the earthquake, linked indirectly with the active tectonics of the region.