丹巴县甲居滑坡复活机制及其稳定性分析   总被引：3，自引：0，他引：3  

李明辉  郑万模  石胜伟  谢忠胜 《山地学报》2008,26(5)

甲居滑坡为一个特大型堆积层古滑坡,因其位于四川省丹巴县甲居藏寨风景旅游区而广受关注.结合滑坡形成的地质环境条件,从滑坡形态、坡体结构、地表变形破坏发育特征等方面人手,对该典型堆积层滑坡进行了分析论述.研究表明,滑坡形成演化历史较为复杂,是一个多级多层滑动形成的非连续复合变形体,其变形复活与滑坡岩土结构、河流侵蚀和人类工程活动密切相关,滑坡具有长期间歇性蠕滑变形特征,以局部滑移为主,难以产生整体性变形破坏,进而为滑坡下一步的监测治理提供了依据.  相似文献   

塔里木盆地库车坳陷盐构造特征及其与油气的关系   总被引：32，自引：9，他引：23       下载免费PDF全文

胡剑风  刘玉魁  杨明慧  郑多明  刘虎  雷刚林  周厉 《地质科学》2004,39(4):580-588

库车坳陷发育古近系和新近系两套膏盐层,其分布特征各异.膏盐层的塑性流动形成多种类型的盐构造.盐构造演化可大致分为4个阶段.前两个发育阶段与盐序列本身及其上覆地层的差异负载作用有关,后两个发育阶段主要与南天山的山前冲断构造作用有关.盐构造在不同的演化阶段具有不同的形态特征,因而对库车坳陷的油气成藏至关重要.盐构造不仅有利于储层发育、油气保存和圈闭形成,而且有利于油气运聚,构成了油气成藏的界限.盐构造发育区是大-中型油气田勘探的有利地区.  相似文献   

Behavior of Marine Clay Subjected to Cyclic Loading with Sustained Shear Stress     

G. Gerald Moses  S. Narasimha Rao 《Marine Georesources & Geotechnology》2013,31(2):81-96

Foundations of offshore structures are designed to withstand a combination of static and cyclic loads due to ocean waves. Wave action on offshore structures can cause a significant amount of cyclic horizontal and vertical forces to be transmitted to the soil through the foundation. In all these cases, these cyclic loads are considered to be superimposed over the initial sustained static stress due to the self-weight of structures. This study considers various factors that influence the development of deformation and pore water pressure in a typical cemented marine clay. These results show that the sustained static shear stress significantly influences the strength and deformation behavior of marine clay under cyclic loading. Up to a certain range of sustained static stress, there is an improvement in strength during cyclic loading and the cyclic strains are greatly reduced.  相似文献   

Observed Variability of Thermohaline Fields,Currents and Eddies in the Western Bay of Bengal During BOBMEX-99     

P. V. Hareesh Kumar  N. Mohan Kumar  T. N. Shyni  A. R. Rao 《Marine Geodesy》2013,36(2):219-233

Field measurements during the Bay of Bengal Monsoon Experiment (BOBMEX-99), data from a deep sea moored buoy, and satellite altimeter were used to describe variability in the hydrographic and meso-scale features in the Bay of Bengal (BoB) during the summer monsoon of 1999. The thermohaline fields showed two regions of upsloping of isopleths centered at 82°E and 84.75°E, ～110 km and 450 km away from the coast, respectively, followed by downsloping. The upsloping/downsloping of isopleths and the alternating currents was part of cyclonic and anti-cyclonic circulation patterns in the western BoB. In this region, both wind and current were important in the dynamics of coastal upwelling. The observations showed a relationship between the propagating waves and eddy on variability of thermohaline fields. On an annual cycle, four Kelvin waves were observed in the BoB, but only the downwelling Kelvin wave formed during October entered the Arabian Sea. During the monsoon season, four eddies were formed in the western BoB, of which the anticyclonic eddy centered at 15°N, 84°E and the cyclonic eddy centered at 17.5°N, 84.5°E were prominent. The baroclinic instability caused by the opposing currents along the east coast and the wind stress curl favored the formation of eddies. Okhubo-Weiss and Isern-Fontanet parameter confirmed the presence of eddies in the BoB.  相似文献   

Millennium recurrence interval of morphogenic earthquakes on the Qingchuan fault,northeastern segment of the Longmen Shan Thrust Belt,China     

Aiming Lin  Bing Yan  Gang Rao 《Journal of Seismology》2016,20(2):535-553

The 2008 M _w 7.9 Wenchuan produced a ～285–300-km-long coseismic surface rupture zone, including a 60-km-long segment along the Qingchuan fault, the northeastern segment of the Longmen Shan Thrust Belt (LSTB), Sichuan Basin, central China. Field investigations, trench excavations, and radiocarbon dating results reveal that (i) the Qingchuan fault is currently active as a seismogenic fault, along which four morphogenic earthquakes including the 2008 Wenchuan earthquake occurred in the past ca. 3500 years, suggesting an average millennium recurrence interval of morphogenic earthquakes in the late Holocene; (ii) the most recent event prior to the 2008 Wenchuan earthquake took place in the period between AD 1400 and AD 1100; (iii) the penultimate paleoseismic event occurred in the period around 2000 years BP in the Han Dynasty (206 BC–AD 220); (iv) the third paleoseismic event occurred in the period between 900 and 1800 BC; and (v) at least three seismic faulting events occurred in the early Holocene. The present results are comparable with those inferred in the central and southwestern segments of the LSTB within which the Wenchuan magnitude earthquakes occurred in a millennium recurrence interval, that are in contrast with previous estimates of 2000–10,000 years for the recurrence interval of morphogenic earthquakes within the LSTB and thereby necessitating substantial modifications to existing seismic hazard models for the densely populated region at the Sichuan region.  相似文献   

Determining tidal turbine farm efficiency in the Western Passage using the disc actuator theory     

Shivanesh Rao  Huijie Xue  Min Bao  Simon Funke 《Ocean Dynamics》2016,66(1):41-57

Tidal power potential is determined across the Western Passage in Passamaquoddy Bay using the Finite Volume Community Ocean Model (FVCOM). The tidal turbines are implemented in FVCOM using the disc actuator theory method to determine the power potential for different densities and arrangements of tidal turbines. At the most efficient setting for 10 turbines across the Western Passage, the optimal turbine drag coefficient is 2.0 and the average power output, in a 2-week period, is ～819 kW. Results suggest that for a single row of turbines, the addition of turbines decreases the efficiency of the turbine farm, but this decrease in efficiency is less than 7 %. A parallel distribution of turbines in an array diminishes the average power for turbines in the shadow of other turbines, while staggered distribution in an array increases the average power extraction for some turbines, due to the speed gains in the gaps between turbines. A simple tidal farm optimization using the OpenTidalFarm (OTF) model suggests a similar tidal farm distribution.  相似文献   

用小波分析提取重力固体潮     

刘明辉  周银兴  叶鹏  李江  林湛  陈阳 《地震地磁观测与研究》2014,35(5)

地球固体潮观测对验证各种地球模型、研究地球内部构造具有重要意义,可为地震预报提供重要的参考依据.BBVS-120甚宽带地震计具有较低的自噪声水平,在低频端输出信号的频率很低,涵盖固体潮信息频带范围.本文提出:BBVS-120地震计输出信号中存在周日波、半日波和1/3日波的固体潮信号,利用小波分析,提取垂直分量中的重力固体潮信号,并作调和分析.  相似文献   

2007年9—11月T213与ECMWF及日本模式中期预报性能检验   总被引：1，自引：0，他引：1  

饶晓琴 《气象》2008,34(2):107-114

2007年9-11月冷空气频繁,气温变幅大,热带气旋活跃,给中期天气预报增加了一定的难度.为积累预报经验,提高中期预报准确率,对9-11月T213模式96小时预报产品进行了天气学检验,并与ECMWF、日本模式进行对比分析.结果表明,T213、ECMWF和日本模式对亚洲中高纬大气环流调整具有较好的中期预报性能,对转折性、灾害性天气的预报有较强指示意义.综合来看,ECMWF对天气系统和要素的预报误差最小,T213模式误差最大,日本模式温度预报性能与ECMWF相当.对0713号台风登陆前的位置和移速,ECMWF预报较为准确,T213模式对台风登陆前移速预报偏慢,对台风登陆后的位置预报偏差最小,日本模式对台风位置和强度预报较为失败.  相似文献   

我国中东部一次大范围霾天气的分析   总被引：27，自引：4，他引：23  

饶晓琴  李峰  周宁芳  杨克明 《气象》2008,34(6):89-96

利用空气污染资料、常规气象观测资料和NCEP再分析资料,对2007年2月5日我国中东部大范围霾天气进行了综合分析.结果表明:前倾槽结构和逆温层结为霾的形成提供了有利条件;800hPa以下层垂直速度、涡度和散度的绝对值较小.是霾维持的动力因子.大气混合层高度的变化对霾的生消有很好指示作用,霾天混合层高度北高南低分布,致使南方比北方更易出现严重霾天气.此外,要素对比结果表明,霾的相对湿度比雾低,温度露点差比雾大,逆温强度比雾弱,大气混合层高度比雾高,这些可为霾的预报提供参考依据.  相似文献   

四川省邻水县土壤锌地球化学特征及玉米水稻籽实锌含量预测          下载免费PDF全文

马旭东  余涛  杨忠芳  张虎生  武芝亮  王珏  李明辉  雷风华 《中国地质》2022,49(1):324-335

[研究目的]锌(Zn)是一种人体所必需的微量元素.利用区域地球化学调查数据,准确预测农作物中Zn含量,从而开展富Zn农产品开发规划仍存在较大难度.[研究方法]本文选择四川省邻水县为研究区,依据土地质量地球化学调查所获得的表层土壤、农作物及根系土中地球化学指标数据,系统研究了土壤与农作物中Zn含量和空间分布特征,分析了玉...  相似文献