Precision estimation and geomorphological analysis based on the DEM generated by InSAR: Taking Damxung-Yangbajain area as an example

Digital elevation model （DEM） can be generated by interferometric synthetic aperture radar （InSAR）. In this paper, the interferometric processing and analyses are carried out for Damxung-Yangbajain area in Tibet, using a pair of Europe remote-sensing satellite （ERS）-1/2 tandem SAR images acquired on 6 and 7 April 1996. A portion of the In- SAR-derived DEM is selected and compared with the 1：50 000 DEM to determine the precision of the InSAR-derived DEM. The comparison indicates that the root mean squared errors （RMSE）, which are used to evaluate error, are about 35, 60, 10, and 15 m in the studied area, mountainous area, basin area and near-fault area, respectively, suggesting that obvious errors are mainly in mountainous area. Besides, the limitation of InSAR technology to generate DEM is analyzed. Our investigation shows that InSAR is an effective tool in geodesy and an important complement to field surveying in some dangerous areas.

念青唐古拉山西布冰川区的冰碛层

念青唐古拉山西布冰川区冰碛物的研究表明 ,在 70 0～ 5 0 0kaBP以来的更新世期间经历了 3次冰期 ,全新世期间经历了 2次冰期和 1次寒冷期 ,形成了可以与青藏高原及邻区相对比的冰碛物系列 ,指示了念青唐古拉山至少自中更新世以来一直处于冰冻圈中。冰碛物中砾石成分的规律性变化反映了念青唐古拉山第四纪期间处于强烈隆升状态 ,冰碛物是盆地同伸展断陷期的堆积物。根据冰碛物与念青唐古拉山南东麓正断层间的关系可以得出 :中更新世以来构成念青唐古拉山南东麓正断层带的主要断层 (F2 )的平均垂直活动速率为 0 .5～ 1.2 5mm/a ,左旋走滑活动速率和相应的垂直活动速率基本上是

试论西藏当雄—羊八井活动构造带的基本特征及其对青藏铁路安全运营的影响

青藏铁路横穿处于强构造活动区和高寒环境的青藏高原,具有复杂的工程地质条件,不仅发育冻土和融冻灾害,而且穿越不同性质的活动断裂。本文分析了铁路经过的当雄-羊八井活动构造带的基本特征,讨论了其对铁路可能产生的严重影响。铁路的开通是工程建设的巨大成就,但是否真正解决了这些地质难题,还有待铁路长期运营的实践和考验。