喀什河断裂中更新世以来的活动速率     

尹光华  裴宏达  蒋靖祥 《地震地磁观测与研究》2007,28(5):155-161

地貌和新近系位错测量的方法是获得活动断裂在新近纪晚期以来可靠和准确的运动学数据的正确方法,本文结合遥感、地貌、变形测量与新近纪测年等手段,重点研究了伊犁盆地喀什河断裂中更新世以来的垂直活动速率.喀什河断裂在中更新世以来的新活动主要表现在河流阶地和地层的位错,综合研究了这些位错数据,分析了断裂各段在中更新世以来的活动速率,讨论了1812年尼勒克地震的平均位错反映断裂现今最新的活动速率,提供了喀什河断裂中更新世以来不同时期活动的定量数据,填补了天山内部新近纪晚期研究的部分空白,对现今地壳运动与地球动力学研究及减轻地质灾害有重要意义.  相似文献   

Review of Research Progresses on the Science of Earthquake Underground Fluid in China During the Last 40 Years     

Liu Yaowei 《中国地震研究》2007,21(1):16-32

This paper presents a review of the development of scientific research and practice of earthquake underground fluid in China during the last 40 years, summaries early constructive research and primary achievements in this field. The science of earthquake underground fluid is closely correlated with earthquake monitoring and prediction, such as innovations in observation techniques and theoretical methods, and analysis of diversified parameters and research into predictive methods. The historical evolution of observation networks for underground fluid indicates that the demand for strong earthquake monitoring and prediction has become the driving force of the construction and development of the observation network. The development of observation techniques represents the trend based on multiform measurement, syntheses, and digitization. The study results of underground fluid theory and precursory mechanisms suggest that the precursory model, numerical simulation and in-door or field experimental research are the main technological approaches promoting innovation. Research results of earthquake forecast methods use physics based forecast techniques and the ideas of combination of usability and scientific advance. It has been proved by forecast practice that studying underground fluid is a very important subject in earthquake prediction on the Chinese mainland. Finally, the primary work and technical criterion on underground fluid are introduced, and some major scientific issues and development trends in different historical stages are summarized.  相似文献   

公元前186年甘肃武都地震考证与发震构造探讨   总被引：6，自引：1，他引：6       下载免费PDF全文

袁道阳  雷中生  何文贵  熊振  葛伟鹏  刘兴旺  刘百篪 《地震学报》2007,29(6):654-663

根据历史地震资料的重新考证和野外调查，认为现行地震目录所给出的公元前186年甘肃武都地震的参数不确切，应做如下修正:其重破坏区位于武都县桔柑乡——舟曲县坪定乡之间，震中位于武都县两河口附近，震级为7~71/4级， 烈度达Ⅸ~Ⅹ度. 这次地震重破坏区长轴方向为北西西向，大致与该区的迭部——白龙江断裂带中东段走向相吻合， 时间上与探槽揭露的该断裂段最晚一次古地震事件的年代（83plusmn;46）BC之前可以对比. 该断裂段至今仍保存有部分地震形变带的遗迹. 综合分析认为，公元前186年武都7~71/4级地震的发震构造应为迭部-白龙江断裂带的中东段.   相似文献   

1573年甘肃岷县地震史料考证与发震构造探讨   总被引：1，自引：0，他引：1  

郑文俊  雷中生  袁道阳  何文贵  葛伟鹏  刘兴旺 《中国地震》2007,23(1):75-83

通过对1573年甘肃岷县地震的历史资料考证和发震构造的综合研究表明:在1573年岷县地震中遭受破坏最为严重的地区位于如今的岷县县城一带(当时为岷州府所在地)。综合各种资料确定1573年甘肃岷县地震震级为621,极震区烈度为Ⅷ~Ⅸ度,震中位于北纬34.4°,东经104.0°,震中精度为2类,震中位置偏差小于或等于25km。该地区构造上位于东昆仑断裂带和西秦岭北缘断裂带的应变传递和构造转换的中间过渡区,其中的临潭-宕昌断裂带活动特性差异明显,只有部分地段表现出全新世活动特征,地震极震区一带分布有不同程度的滑坡和基岩崩塌等。综合分析认为,临潭-宕昌断裂带的岷县-宕昌段是甘肃岷县1573年621级地震的发震构造。  相似文献   

极地气象与全球变化   总被引：1，自引：0，他引：1  

卞林根  陈百炼  辛羽飞 《气象》2007,33(3):3-9

目前，全球变化加快，极地地区变化尤为突出，这对区域或全球的社会、经济和生态系统都将产生显著的影响。最明显的证据是极区的冰川和冰雪范围持续减少，永久冻土在消融和消失，北冰洋海冰范围和厚度减小。极地环境的变化跟地球其它区域的变化息息相关，如臭氧洞的形成与来自低纬度的污染物积聚有关。极地地区的科学研究非常重要，不断地给我们提出新的科学挑战。极地冰盖下和大面积海冰下存在着大量的未知领域，许多极地研究的前沿问题实际上存在于传统学科的交叉领域。因此，世界气象组织（WMO）和国际科联（ICSU）共同发起并于2007年3月1日启动实施2007-2008年国际极地年（IPY），旨在为极地气象学、海洋学、冰川和水文学等领域的科学研究和观测做出贡献，有助于发展更精确的海一冰一大气环流模式，进一步提高对天气预报和气候变化的预测和预估水平。  相似文献   

应用卫星遥感技术监测大气痕量气体的研究进展   总被引：8，自引：2，他引：8  

张兴赢  张鹏  方宗义  邱红  李晓静  张艳 《气象》2007,33(7):3-14

大气污染是全球环境变化的焦点,传统的地面定点监测大气污染技术已经越来越不能满足科学研究和国家决策的需求,大尺度卫星遥感大气污染技术作为一种新兴的研究手段,可以得到大尺度、长时间序列的污染物时空分布特征和变化趋势,进而研究大气化学变化对全球气候和生物地球化学循环的影响。对卫星遥感大气痕量气体科学领域的发展和国际上使用的各类大气痕量气体传感器以及所取得的科研成果进行了全面的综述,结合中国地区的自身特点,提出我国利用卫星遥感技术研究大气成分的思路和未来开展科研工作的方向。  相似文献   

业务单位开展科研和技术开发工作的思考     

葛蕾 《广西气象》2007,28(4):86-87,90

通过对业务部门10多年来从事科研组织管理工作的分析,找出了业务单位开展科研与技术开发的对策与措施,对发挥各级气象业务部门的作用,提高气象预报服务质量,加强人才的培养,开展科研和技术开发工作是十分必要的。  相似文献   

A Conceptual Framework for Enhancing the Utility of Rainfall Hazard Forecasts for Agriculture in Marginal Environments   总被引：1，自引：0，他引：1  

Muhammad?T.?UsmanEmail author  Emma?Archer  Peter?Johnston  Mark?Tadross 《Natural Hazards》2005,34(1):111-129

Semi-arid and dry sub-humid areas (especially in the tropics) are characterized by high inter-annual and intra-seasonal rainfall variability. Agriculture, which employs the bulk of the rapidly increasing populations, is largely rain-fed, low-input based and highly resource dependent. Recent spates of drought have, therefore, exacerbated the now-too-familiar specter of famine and starvation in these areas with glaring examples being the recurring episodes in sub-Saharan Africa since the great Sahel drought of 1969–1973. A great need for accurate and timely hazard forecast products in aid of agriculture thus exists.Several schemes are currently employed by various agencies around the globe in this direction. There does remain, however, a gap between product provision and user expectations. This paper examines this gap suggesting a five-point framework within which it can be addressed as an action agenda for the climate science community. The paper posits that changes are possible to existing methodologies (related to three of these points), which, within the context of current science, can greatly enhance the utility of forecast products for agriculture in marginal areas. The remaining two points have, however, been identified as requiring additional applied research and necessary pointers for addressing these issues are provided. First is the need for appropriate impact-related indicators for intra-seasonal and interannual rainfall variability that are easy to compute, amenable to forecasting and follow closely the experiences of farmers in marginal areas. The second is a consideration of appropriate forecast information formatting and communication medium that guarantee effective feedback between forecast producers and users. Specific examples of the status quo and of work currently underway are cited from southern Africa – a region currently attracting international attention as a result of recent droughts and the threat of famine.  相似文献   

International standard (ISO) on seismic actions for designing geotechnical works–An overview     

Susumu Iai   《Soil Dynamics and Earthquake Engineering》2005,25(7-10):605-615

The seismic performance of geotechnical works is significantly affected by ground displacement. In particular, soil–structure interaction and effects of liquefaction play major roles and pose difficult problems for engineers. An International Standard, ISO23469, is being developed for addressing these issues in a systematic manner within a consistent framework. The objective of this paper is to give an overview of this International Standard.In this International Standard, the seismic actions are determined through two stages. The first stage determines basic seismic action variables, including the earthquake ground motion at the site, the potential for earthquake-associated phenomena such as liquefaction and induced lateral ground displacement. These basic variables are used, in the second stage, for specifying the seismic actions for designing geotechnical works. In the second stage, the soil–structure interaction plays a major role. Types of analyses are classified based on a combination of static/dynamic analyses and the procedure for soil–structure interaction classified as follows:

– simplified: soil–structure interaction of a global system is modeled as an action on a substructure;

– detailed: soil–structure interaction of a global system is modeled as a coupled system.

Land, ethnic, and gender change: Transnational migration and its effects on Guatemalan lives and landscapes   总被引：1，自引：0，他引：1  

Matthew J. Taylor  Michelle J. Moran-Taylor 《Geoforum》2006,37(1):41-61

Migration to the United States of America from Guatemala effects many aspects of Guatemalan life. We document, through extensive ethnographic fieldwork, how migrants and their remittances effect gender relations, ethnicity, land use, and land distribution. Our evidence is drawn from research in four communities. San Pedro Pinula and Gualán represent communities of eastern Guatemala. San Cristóbal Totonicapán is an Indigenous town in Guatemala’s western highlands, and San Lucas is a lowland frontier community in the Guatemalan department of Ixcán, which borders Chiapas, Mexico. Our results reveal that migrants and their remittances, both social and tangible, result in significant changes in land use and land distribution in Ixcán. Migrant money permits the conversion of rainforest into cattle pasture and also results in the accumulation of land in the hands of migrants. In terms of land use, we see in San Pedro Pinula that migrant money also allows the Pokoman Maya to make small entries into the Ladino (non-indigenous) dominated cattle business. In San Pedro Pinula, the migration and return of Maya residents also permits them to slowly challenge ethnic roles that have developed over the last five centuries. When we look at how migration effects gender roles in Gualán and San Cristóbal we also note that migration and social remittances permit a gradual challenge and erosion of traditional gender roles in Guatemala. We point out, however, that migration-related changes to traditional gender and ethnic roles is gradual because migrants, despite their increased earnings and awareness, run into a social structure that resists rapid change. This is not the case when we examine land transformations in Ixcán. Here, migrants encounter few barriers when they attempt to put their new money and ideas to work. Despite the advantages that migration brings to many families, especially in the face of a faltering national economy and state inactivity regarding national development, we conclude that migration and remittances do not result in community or nation-wide development. At this stage migrant remittances are used for personal advancement and very little money and effort is invested in works that benefit communities or neighborhoods. We call for continued studies of the effects of international migration on Guatemalan hometowns that build on our initial studies to better understand the longer-term ramifications of migration in a country where no community is without migrants.  相似文献