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51.
Preliminary results of measuring the crustal deformation in Qinghai-Xizang area using GPS technique 总被引:5,自引:0,他引:5
GPS repetition measurement tbta in Qinghai-Xizatlg (Tibetan) area in 1992 and 1994 have been used to determine the change
rates of seven bascline vectors of Lhasa-Wenquan, etc. It is the first time to obtain the direct observation results of the
large-scale crustal horizontal motions in this area. Thesc preliminary results also for the first time provide the direct
observation evidence for some important geophysical and geological viewpoints, such as the northward gradual reduce of the
effect of the northward push-pressing to Eurasian continent by Indian Plate in the Qinghai-Xizang area, having a southward
strike slip movement of the Chuan-Dian diamond block, etc. 相似文献
52.
Stretching characteristics and its dynamic significance of the northern continental margin of South China Sea 总被引:5,自引:0,他引:5
Zhang YunFan Sun Zhen Zhou Di Guo XingWei Shi XiaoBin Wu XiangJie Pang Xiong 《中国科学D辑(英文版)》2008,51(3):422-430
To investigate the thinning of the whole crust, and the contribution of the upper versus lower crust to the stretching since Cenozoic, we calculated the stretching factor of the northern margin of South China Sea with data such as whole crustal thickness, depth of Cenozoic sedimentary basement and the horizontal displacement of faults. An isometric line drawing on whole crustal stretching factor is then obtained. Along the seismic Line 1530 in Baiyun sag, we also calculated the stretching factors of the upper and lower crust. The results suggest that the whole crustal thickness decreases seaward while the whole crustal stretching factor increases from shelf to slope. The Moho upwells highest beneath where the crust is thinned most. The value of the whole crustal stretching factor ranges from 1.5 to 6. Two areas were thinned intensely: the center of Yinggehai Basin, and the Baiyun sag in the Pearl River Mouth Basin. The calculation of the upper and lower crustal stretching factors from DSP1530 in Baiyun sag shows that the original crust of Baiyun sag should be thinned before deformation. Its pre-Cenozoic evolution as well as tectonic position during Cenozoic might be responsible for that. 相似文献
53.
Introduction Greeting the coming of the 21st century, Professor HU Yu-xian and other Chinese scholars briefed the trend of earthquake engineering in China and aboard (HU, 1999; HU, ZHOU, 1999). The experiences and lessons learning from the destructive earthquakes in China and abroad in re-cent years, the damage action of the large velocity impulse in ground motion in near field in seis-mic design, numerous earthquake examples show that there are many weaknesses in aspects of earthquake p… 相似文献
54.
Chen Shun-yun Xu Zhao-yong Yang Run-hai Zhao Jin-ming Hao Jin-qi Wang Yun-yun Xiong Bing-heng Wang Zheng-rong 《地震学报(英文版)》2002,15(6):656-666
Based on the phenomena that the deformation gap was observed before the great Tangshang earthquake, this paper discusses the
strain gap according to test and theory. The (strain) patterns were recorded photographically by realtime holographic interferometry
and shadow optical method of caustics, as soon as the loading process started. In the meantime, the AE (acoustic emission)
signals were recorded by a micro crack information storage-analysis system. According to damage theory and location of micro
fracture, we have studied the stain gap and gained: a) It is necessary that strain gap appears under the condition of linear
elasticity theory, and its situation is relatively stable, corresponding to stress concentration. b) Micro fractures, which
appear initially at area of high stress, occur rarely at the strain gap, and their locations are finally in the zone between
the stress concentration area and the strain gap, which indicate the clusters or groups. However, the major macro fracture
(final rupture) started from the shadow areas, and then grew quickly towards the strain gaps, which resulted in failure of
sample.
Foundation item: The Dual Project of China Seismological Bureau (9691309020301), the Specialized Funds for National Key Basic Study (G1998040704),
the project for the MOST under contract (2001BA601B02) and Youth Funds for applied basic study of the Science and Technology
Bureau of Yunnan Province (98D019Q). 相似文献
55.
基于T-S模糊神经网络的采空塌陷危险性判别 总被引:1,自引:0,他引:1
采空区地面塌陷的危险性判别受地质因素、采矿因素等多重因素的影响,各因素往往影响程度不同且部分因素之间又相互联系。为了能够较准确地对采空塌陷危险性进行评估,引入了T-S模糊神经网络模型。以北京西山地区采空塌陷为例,根据塌陷特点,分别选取了地质构造复杂程度、覆盖层类型、第四系覆盖层厚度、覆岩强度、煤层倾角、采深采厚比、采空区埋深、采空区空间叠置层数8项影响因素作为评价指标,并建立了分级标准。将单因素评价指标均匀线性插值作为训练样本,建立了T-S模糊神经网络判别模型。利用训练好的神经网络模型对选取的8处采空区进行评估,结果分别为:Ⅰ、Ⅱ、Ⅲ、Ⅱ、Ⅲ、Ⅱ、Ⅲ、Ⅱ,结果与实际情况吻合。研究表明,利用T-S模糊神经网络研究采空塌陷危险性是可行的。 相似文献
56.
城市居民时空行为序列模式挖掘方法 总被引:1,自引:0,他引:1
通过问卷调查获得北京市500个家庭的活动日志数据.运用序列比对方法对时空行为序列数据进行序列模式挖掘,对每类序列模式通过频繁模式挖掘出其中潜在有用的行为模式.试验结果表明,序列比对方法与频繁模式挖掘相结合在城市居民行为模式分析中应用成功,其弥补了传统数据分析方法的不足,为复杂时空行为数据的分析提供了一种新视角. 相似文献
57.
58.
59.
陕西不同生态区苹果品质差异及与气象因子的关系 总被引:2,自引:0,他引:2
为做好苹果气候品质认证工作,基于2013—2015年陕西31个苹果种植生产基地县155片果园的果实品质调查数据和物候监测资料,应用灰色关联度分析和逐步回归方法,分延安果区、渭北东部果区、渭北西部果区和关中果区4个生态类型区,分析了苹果品质的分异特征,研究了影响苹果品质的关键物候期及主要气象因子。结果表明:各生态类型区的果形指数和可滴定酸含量较为一致,单果重、可溶性固形物含量和果实着色度差异较为明显。第一次膨大期最高气温、生长季最高气温和幼果期平均气温对苹果品质的影响最为显著。其中开花期和幼果期气温高、降水少,第一次膨大期气温低、日照多,着色期气温低、相对湿度大有利于提高陕西苹果品质。利用多元回归构建的品质预测模型拟合效果较好,可在业务中应用。 相似文献
60.
The midwinter suppression(MWS) of the North Pacific storm track(NPST) has been an active research topic for decades. Based on the daily-mean NCEP/NCAR reanalysis from 1948 to 2018, this study investigates the MWS-related atmospheric circulation characteristics in the Northern Hemisphere by regression analysis with respect to a new MWS index, which may shed more light on this difficult issue. The occurrence frequency of the MWS of the upper-tropospheric NPST is more than 0.8 after the mid-1980 s. The MWS is accompanied by significantly positive sea-level pressure anomalies in Eurasia and negative anomalies over the North Pacific, which correspond to a strengthened East Asian winter monsoon. The intensified East Asian trough and atmospheric blocking in the North Pacific as well as the significantly negative low-level air temperature anomalies, lying upstream of the MNPST, are expected to be distinctly associated with the MWS. However, the relationship between the MWS and low-level atmospheric baroclinicity is somewhat puzzling.From the diagnostics of the eddy energy budget, it is identified that the inefficiency of the barotropic energy conversion related to the barotropic governor mechanism does not favor the occurrence of the MWS. In contrast, weakened baroclinic energy conversion, buoyancy conversion, and generation of eddy available potential energy by diabatic heating are conducive to the occurrence of the MWS. In addition, Ural blocking in the upstream region of the MNPST may be another candidate mechanism associated with the MWS. 相似文献