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11.
The evaluation of potential rock slope problems using stereographic projection techniques known as kinematic analysis is one of the most important parts of a slope stability investigation to be carried out in jointed rock media. In conventional stereoprojection techniques for the assessment of possible rock slope failures, the peak orientations of joints together with the slope geometry and the friction angle of the weakness planes are used. Other possible joint orientations which may be encountered in the rock media are ignored, although they belong to the group of joint peak orientations. In this study, nearly vertical jointed andesites cropped out at the Altindag settlement region in Ankara were studied in order to evaluate the relevance of this ignored discontinuity orientation data on slope stability. As a result, probabilistic risk maps for planar, toppling and wedge failures were produced using the kinematic rules and digital elevation model of the study area. The comparison of the distribution of the actual failures in the area and the probabilistic risk maps prepared for the study area revealed that all of the identified failures are found to be located in the higher risk zones on the probabilistic risk maps.  相似文献   
12.
《The Journal of geography》2012,111(4):143-155
This article examines possibilities associated with the cultivation of balanced regional images via the use of simple methods. Two experiments based on the primacy effect and the painting picture rule, or visual depiction of regions, were conducted. The results show significant differences in the formation of regional images. More specifically, the presentation of positive prior knowledge and the depiction of regional aspects with strong visual cues led to the formation of regional images that were more balanced. In conclusion, these simple teaching methods are effective for cultivating balanced regional images, an important element of geography education.  相似文献   
13.
安徽安庆月山岩体的磁组构及古地磁特征   总被引:3,自引:0,他引:3  
阎桂林  张鸣 《地球科学》1990,15(6):667-673
  相似文献   
14.
This paper deals with the morphotectonic evaluation of the Delhi region in northern India to understand its impact on land use and urban development. To accommodate heavy urbanization and population rise (being the capital of India), the area has undergone tremendous environmental degradation resulting from a mismatch between adopted land use and morphotectonic considerations. The geomorphic and drainage signatures of the region have evolved out of interaction of varied geological parameters including neotectonic activities. We have evaluated the changes in the drainage pattern of the Yamuna River in the Delhi region to underline its significance in geomorphic evolution and subsequent land use and/or land suitability. The Yamuna River has shown variations both in channel position and geometry over the last two centuries. The observed migration pattern of the river (shifting of confluences, position and disposition of palaeochannels, etc.,) cannot be attributed to normal river phenomenon and appears to have been effected by neotectonic changes. In addition, some case studies are discussed to underline the significance of geomorphic factors in urban development.  相似文献   
15.
《Urban geography》2013,34(4):360-382
Many European urban regions have experienced a transformation from a compact monocentric toward a less compact polycentric urban region since the 1960s. The debate on emerging polycentricity in Europe so far tends to be more theoretical than analytical. The trend toward increasingly polycentric urban regions is meanwhile beyond dispute, but the effects of this transformation on urban regions and their components have only been explored to a limited extent. Are the "old" central cities only losing people, functions, and status to the new urban centers, or do these centers complement each other and specialize in terms of economic activities and population composition? This article presents evidence for the Amsterdam urban region regarding population distribution, selective migration, job growth, and economic specializations of the region's subcenters. It will become clear from our data that the Amsterdam urban region has indeed become more polycentric, but also that Amsterdam has managed to remain a vital center. The newer and older urban subcenters have become increasingly important, but rather than competing with Amsterdam, they develop in a complementary way.  相似文献   
16.
东喜马拉雅南迦巴瓦峰地区地质构造十分复杂,对该区板块缝合带的空间位置问题,长期以来,一直认为沿雅鲁藏布江呈弧形展布。笔者以ETM+为主要信息源,以遥感与GIS为技术支撑,对南峰地区的断裂构造进行了详细的遥感解译分析,从构造统计分析的角度对断裂构造进行定量研究,从分维值及趋势值的空间分布及变化特征分析,认为缝合带的南东段、北段大致沿雅鲁藏布江展布,而北西段位于雅鲁藏布江的北西侧,沿东久-米林(断裂带)展布,这也与近几年来开展了1∶25万区域地质调查获得的新认识相一致。  相似文献   
17.
甘肃陇南市武都区小水沟泥石流治理防治工程   总被引:2,自引:0,他引:2  
2008年5.12汶川特大地震对甘肃省陇南市造成了严重危害。震后次生地质灾害对陇南市城镇村庄、交通和人民群众生命财产安全造成严重威胁。武都区蒲池乡小水沟震后产生了大量的崩塌、滑塌堆积体,一旦遭遇暴雨,极易发生泥石流灾害,直接危及小水沟沟口左岸九年制义务学校一座及沟口两岸居民,因此治理该泥石流沟是十分必要的。通过对当地暴雨特征、地层岩性、地质构造、泥石流固体物质源及形成的踏勘,针对该泥石流具有危险度高,流量大的特点,执行全面规划、重点治理的设计思路,采取了防护、生物工程相结合的综合防治措施。拦挡工程为有效发挥工程泻洪、拦渣、调节、固床、稳坡和控制固体物质补给量,预防沟道下切及沟壑发展,减少泥石流对下游村庄危害,起到了积极作用;生物工程的主要作用是稳固堤前砂土、减缓水石流流速、减小水石流对护堤的直接冲蚀和破坏、保障堤内居民生命财产安全和耕地的正常使用、增大植被覆盖率,绿化环境等。  相似文献   
18.
本文通过对豫东、豫北等河南农业主产区80年代以来工业化进程的调研分析,在总结经验教训的基础上,针对这些地区工业发展的特殊条件,提出了平原农区工业化的基本思路和途径,主导产业的选择和注意处理的几个问题。  相似文献   
19.
《湘绮楼日记》记录的湖南长沙1877-1878年寒冬   总被引:5,自引:4,他引:5  
在对清代王运所著的《湘绮楼日记》中长达40余年(1869—1916)的冬季(12月—2月)天气记录进行整理之后,从王运在湖南长沙、衡阳一带记录的30多个完整冬季之中,提取了一个特殊的寒冬——1877—1878年冬天(记录于长沙境内)。将这年的天气记录与日记中其他年份进行比较,其寒冷程度可以明显地体现在以下几个方面(1)降雪——降雪日数14天,为最多的年份之一,且降雪次数最多;(2)积雪——积雪日数在27天以上,为历年之最;(3)冰冻——根据该年日记记录,冰冻的严重程度和持续时间均超过其他年份;(4)《日记》作者感受——王运留下了大量对“寒”、“暖”的感应记录,这一年有历年最多的“寒”记录(15条)和最少的“暖”记录(0)。由此可以得出结论1877—1878年冬天是《湘绮楼日记》中所仅见的、异常寒冷的严冬。文中对这年当地冬季严寒的天气过程和气候特点进行了初步分析。  相似文献   
20.
Detailed palaeomagnetic and rock magnetic analyses provide improved palaeomagnetic results from 23 sites in the Borgmassivet intrusions in the Ahlmannryggen region of Dronning Maud Land, East Antarctica. These intrusions are of similar age to their host, the ca. 1130 Ma Ritscherflya Supergroup (RSG). A mean direction of D=235.4°, I=−7.6° with k=45.9 and α95=4.5° was obtained from this study. When combined with previously reported results from 11 sites in the same region, including sites from the Ritscherflya Supergroup, it gives an overall mean direction for 34 sites from the igneous suite with D=236.5°, I=−3.6°, k=27.9 and α95=4.8°. Isothermal remanent magnetization (IRM) experiments on several specimens suggest magnetite or titanomagnetite as the primary remanence carrier, while high temperature magnetic susceptibility experiments indicate the presence of single domain particles. These observations, together with field evidence and the high coercivities and unblocking temperatures, support a primary origin for the observed characteristic remanence. The Borgmassivet palaeomagnetic pole lies at 54.5°E, 8.3°N with A95=3.3°. If Antarctica is moved to its Gondwanan position adjacent to southeast Africa, the Borgmassivet pole (BM) coincides with that of the African well-established, well-dated (1100 Ma) Umkondo Large Igneous Province pole, supporting the hypothesis that the Grunehogna craton of Dronning Maud Land was part of the Kalahari craton of southern Africa at ca. 1100 Ma.  相似文献   
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