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101.
华南地区崩岗侵蚀灾害及其防治 总被引:9,自引:0,他引:9
刘瑞华 《水文地质工程地质》2004,31(4):54-57
根据区域调查和定位研究资料,介绍了华南地区崩岗侵蚀及其灾害特点,概述了崩岗的形成、发育规律及其演变过程,分析了崩岗侵蚀及其灾害的影响因素。提出进行崩岗灾害防治时,应在水土保持传统方法基础上,整合水文地质学和工程地质学及其它相关学科理论,应用GIS技术对崩岗侵蚀进行科学监测和管理,为坡地利用和环境整治以及灾害防治提供依据。 相似文献
102.
KERR ANDREW C.; TARNEY JOHN; KEMPTON PAMELA D.; PRINGLE MALCOLM; NIVIA ALVARO 《Journal of Petrology》2004,45(9):1877-1906
The fault-bounded Bolívar Ultramafic Complex (BUC) onthe eastern fringes of the Western Cordillera of Colombia wastectonically accreted onto the western coast of South Americain the late Cretaceousearly Tertiary, along with pillowbasalts of the CaribbeanColombian Oceanic Plateau (CCOP).The complex consists of a lower sequence of ultramafic cumulates,successively overlain by layered and isotropic gabbroic rocks.The gabbros grade into, and are intruded by, mafic pegmatitesthat consist of large magnesiohornblende and plagioclase crystals.These pegmatites yield a weighted mean 40Ar39Ar step-heatingage of 90·5 ± 0·9 Ma and thus coincidewith the timing of peak CCOP volcanism. The chemistry of theBUC is not consistent with a subduction-related origin. However,the similarity in SrNdPbHf isotopes betweenthe CCOP and the BUC, in conjunction with their indistinguishableages, suggests that the BUC is an integral part of the plume-derivedCCOP. The parental magmas of the Bolívar complex wereprobably hydrous picrites that underwent 2030% crystallization.The residual magmas from this fractionation contained 相似文献
103.
Natural disasters like floods, tornadoes, tropicalcyclones, heat and cold wavewreak havoc and cause tremendous loss ofproperty all over the world. Most ofthe natural disasters are either dueto weather or are triggered due toweather related processes.Extreme weather events claimed thousands oflives and caused damage on vastscale. Recent super cyclone which affectedOrissa in 1999, Bangladesh cyclone of1970 and Hurricane Andrew in 1992 areexamples of some of the more damagingtropical cyclones which affected developingas well as the developed world. Heatand cold waves are also extreme events,which cause enormous losses in terms oflives lost and human discomfort and ailmentsarising out of them. The heat waveof 1995 and 1998 are still fresh in the mindof the Indian public. The estimated lossof human lives due to heat wave in 1998 was morethan 15,000. Economic losses asa result of these disasters and in particular inassociation with tropical cyclones haveincreased enormously over the last three decades.During 1961–1991, total loss oflives from drought alone was 1,333,728 overthe whole world. In terms of economiclosses, there is 8–10 fold increase from thebase figure of 1960. The socio-economicimpact of natural disaster is complex dependingupon the vulnerability of the placeand mitigation strategies that are put in place.Meteorology plays a crucial role in forewarningpeople about the severe/extremeweather systems and a constant endeavour by themeteorological services worldover has gone a long way towards minimizing thelosses caused by natural disasters.The paper summarises the natural disasterstatistics over south Asia and the possibleprediction strategies for combating theirsocio-economic impacts. 相似文献
104.
The temperature appeared rising trend during the 20th century in China's tropics.Two cooling stages and two warming stages in the process of climatic fluctuation can be recognized.After the 1980s the climate is the warmest which corresponds to the global change,but the warmest period is the 1940s in Kunming.The climate pattern mostly appears contemporaneity of warming and humidity,which is different from the situation of whole China.The natural disasters tend to be aggravated.The number of typhoons increased.Flood damages occurred frequently in the years of more typhoons.The number of droughts and cold damages increased.It was snowed in Guangzhou.There was frost in Haikou and Yaxian.Four years of heavy snow have been recorded in Kunming. 相似文献
105.
日本国内旅游业的发展及其地域特征 总被引:1,自引:1,他引:1
日本旅游业已成为国民经济的重要部门,据2002年日本交通省的统计表明,观光产业GDP已占国内生产总值的2.2%,这一数字与美国相近。但与西方国家显著不同的是,在美、英、法、意等旅游业发达国家中,国际旅游业占据举足轻重地位,而日本的旅游业却以国内旅游为主体。据日本最大旅行社JTB的统计,2002年日本旅游出行人数为34013万人次(其中出国旅游1664万人次),而同年日本接待的外国入境游客刚刚超过500万人次。本文旨在介绍和分析日本国内旅游业的发生、发展的变化特征,以及国民不同的旅游方式和旅游地域差异。 相似文献
106.
M. E. Dickson 《The Australian geographer》2004,35(2):223-238
Lord Howe Island is a small eroded remnant of a Late Miocene shield volcano. A fringing coral reef dissipates wave energy along a portion of the shoreline, but the remainder of the coast is rugged with spectacular high basaltic sea cliffs. This paper investigates the evolution of talus slopes that occur beneath the loftiest cliffs, and places this analysis within the context of a longer history of island planation that has resulted in a wide truncated shelf around the island. During the Last Glacial, when the sea level was lower than at present, talus slopes accumulated around the extent of the island's cliffed coast because material eroded from cliffs by subaerial processes could not be removed by marine processes. The survival of these slopes during the Holocene has depended on a balance achieved between rates of subaerial and marine erosion. This balance is fundamentally influenced by cliff height, as cliffs higher than 200 m are plunging or veneered by talus slopes, whereas lower cliffs have erosional shore platforms. On comparison with published erosion rates from inland basalt scarps it appears that marine processes may account for over 90 per cent of the total cliff retreat that has occurred at Lord Howe Island, yet contemporary coastal morphology attests to the significance of subaerial processes in recent times. It is likely that marine cliffing was very rapid soon after volcanism ceased, but rates of erosion decreased through time as wave energy became increasingly attenuated across a widening planation surface, and as increasing cliff heights yielded greater quantities of talus that provided protection from rapid marine erosion. 相似文献
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随着我国机构改革的不断深入和社会主义市场经济体制的逐步建立和完善,地震学会同其他社会团体一样将成为现代社会的支柱之一。以山西省地震学会目前的工作现状为例,指出学会在管理体制、运行机制和活动方式等方面存在的问题,提出了发展思路及建议。 相似文献