浙西的加里东运动   总被引：1，自引：1，他引：0  

陈忠大  吴小勇 《浙江国土资源》1996,(2)

作者运用地层超覆面展平的方法，在浙西上古生界超覆面展平图中，勾绘了浙西加里东运动形成的古地质图，显示了浙西地区加里东运动的表现，是一个轴迹走向北东的平缓开阔的褶皱运动。通过1：5区域地质调查研究，浙西汾口测区多期褶皱的剖析，证明浙西的加里东运动不仅是简单的局部的升降运动，而且是具一定方向性的广泛的褶皱运动；同时发生浅变质作用叠加于前震旦系岩层之中，后经印支期褶皱叠加形成浙西富有特色的花边褶皱。此外，本文还阐述广浙西加里东运动所形成的褶皱轴迹方向的转换的成因与机理。  相似文献   

Analysis on monitoring crust movement by using GPS in Qinghai-Xiqang Plateau     

Hongxiang Cai  Chenghua Song  Jingnan Liu 《中国科学D辑(英文版)》1997,40(3):300-305

Based on the analysis of the 1993 and 1995 GPS data acquired from crust movement and deformation monitoring in thc Qinghai-Xizang Plateau, the following preliminary conclusions could be drawn: the levelly moving rate and direction of the land massifs in the Qinghai-Xizang Plateau tally with the viewpoint generally held by geologists and geophysicists irr recent years; the accuracy of monitoring crust movement has reached the world advanced level; the result has provided valuable and reliable information to the quantitative analysis of the modern crust movement and deformation in the plateau. Project supported by the Nntional Natural Science Foundation of China.  相似文献   

浙江省萧山—富阳前震旦纪双重基底及构造演化     

包超民 《浙江国土资源》1995,(2)

萧山—富阳一带的前震旦系，分别由中元古代陆缘岛弧型双溪坞群火山岩、新元古代青白口纪河上镇群弧后盆地沉积和双峰式陆相火山岩组成。中元古代末的神功运动表现强烈，青白口纪末的晋宁运动叠加褶皱明显。剖面连续完整，地质现象丰富．是华南重要的层型剖面。  相似文献   

局部热膨胀产生的重力异常及其构造意义     

杨学祥  杨文瑛 《大地测量与地球动力学》1995,(1)

地热梯度的增加不仅引起地壳的体积变化，而且使地壳的荷载发生变化。定量计算表明，在均衡深度以上，局部地壳地热梯度的增加将产生重力负异常。随之而来的地壳均衡运动会造成２ｋｍ左右的地壳上升，用以补偿膨胀后地壳的质量亏损。  相似文献   

中国大陆部分地区的地壳垂直运动   总被引：11，自引：7，他引：4  

黄立人  马青  王若柏 《大地测量与地球动力学》2004,24(4):7-12

利用 195 2～ 2 0 0 2年间我国大陆部分地区 (90 .5°～ 12 7.3°E ,2 1.5°～ 4 4°N)的精密水准测量结果研究了这些地区的现今地壳垂直运动及其发展演变特点。将 5 0年的地壳运动分成两个时间段 :第一时间段的中心时刻 (资料观测时间的平均值 )为 1972 .87;第二时间段的中心时刻为 1983.17。对于这两期资料都采用了伪逆基准下的线性动态运动模型 ,求得的运动速率都归算到北京水准原点 (假定北京原点的运动速率为零 )。  相似文献   

3D numerical simulation of seagrass movement under waves and currents with GPUSPH     

《国际泥沙研究》2021,36(6):711-722

The current study tries a new approach to simulating interactions between waves and seagrass through Smoothed Particle Hydrodynamics (SPH). In this model, the plants are defined as a solid that respects Hooke's law, and are assumed to have direct interaction with the fluid. Given the characteristics of the SPH method, especially in terms of computational time, the dimensions of the simulations were limited. The first goal of the current study was to optimize the approach to avoid reaching certain limits such as the rupture of the simulated plant. Plant movements under waves and/or currents have been studied by several authors in various in-situ, physical, and numerical experiments concerning various vegetation species, thus proving that plant movements can be successfully reproduced by SPH 2D/3D. Manning's roughness coefficient, n, was calculated to confirm that the results were in accordance with what had been measured in flume studies. Even though there is still room for improvement, it is shown that this method can be used to estimate Manning's coefficient for coastal vegetation (seagrass and saltmarsh vegetation) and to greatly improve the modeling and forecasting of coastal erosion and storm surge risks by including the effects of vegetation in integrated models.  相似文献   

穿越活断层铰链式衬砌隧道减震措施动力响应研究   总被引：2，自引：1，他引：1       下载免费PDF全文

姬云平 《地震工程学报》2021,43(4):909-919

鉴于穿越地震活动带逆断层的铁路山岭隧道易受逆断层滑动的影响,且目前铁路隧道穿越多条活动性断层可供借鉴经验较少的现状。文章采用数值分析方法,对活动逆断层错动下的铰链式衬砌隧道在地震荷载作用下围岩加固方式、超挖设计结构的动力响应进行对比分析。结果表明逆断层错动时,对浅部地层变形的影响范围大于深部,但最大附加变形出现在深部断层面附近,且错距越大其最大附加变形值越大,断层活动对隧道结构安全影响较为显著。注浆加固并不改变衬砌在地震中的震动频谱特性,宜采用施作单层衬砌预留修复空间的设计方案。对于是否超挖设计的两种工况下,衬砌位移变化规律一致,衬砌的震动频谱特性一致。经过监控量测发现支护压应力在埋设2个月左右后趋于稳定。所得结论可为今后类似工程结构设计与施工提供参考。  相似文献   

中国地壳运动观测网络基准站重力场变化的海潮负荷信号改正问题   总被引：7，自引：0，他引：7  

孙和平  周江存 《地球科学进展》2002,17(1):39-43

利用最新的全球海潮模型（Csr3．0，Fes95．2，Tpxo2和Csr4．0）和原有的Schwiderski海潮模型以及中国近海海潮数据和标准地球模型负荷格林函数，采用直接褶积积分方法研究了中国地壳运动观测网络25个基准站重力固体潮观测中的海潮负荷效应问题，计算了 8个主要潮汐波的负荷振幅和相位，构制了北京和上海等10个台站重力负荷随时间变化函数。  相似文献   

Magma transfer processes at persistently active volcanoes: insights from gravity observations     

Corinne A. Locke  Hazel Rymer  John Cassidy 《Journal of Volcanology and Geothermal Research》2003,127(1-2):73-86

Magma transfer processes at persistently active volcanoes are distinguished by the large magma flux required to sustain the prodigious quantities of heat and gas emitted at the surface. Although the resulting degassed magma has been conjectured to accumulate either deep within the volcanic edifice or in the upper levels of the sub-edifice system, no direct evidence for such active accumulation has been reported. Temporal gravity data are unique in being able to quantify mass changes and have been successfully used to model shallow magma movements on different temporal scales, but have not generally been applied to the investigation of postulated long-term accumulation of magma at greater spatial scales within volcanic systems. Here, we model the critical data acquisition parameters required to detect mass flux at volcanoes, we review existing data from a number of volcanoes that exemplify the measurement of shallow mass changes and present new data from Poas and Telica volcanoes. We show that if a substantial proportion of degassed magma lodges within the sub-edifice region, it would result in measurable annual to decadal gravity increases occurring over spatial scales of tens of kilometres and propose that existing microgravity data from Sakurajima and, possibly, Etna volcanoes could be interpreted in these terms. Furthermore, such repeat microgravity data could be used to determine whether the accumulation rate is in equilibrium with the rate of production of degassed magma as calculated from the surface gas flux and hence identify the build-up of gas-rich magma at depth that may be significant in terms of eruption potential. We also argue that large magma bodies, both molten and frozen, modelled beneath volcanoes from seismic and gravity data, could represent endogenous or cryptic intrusions of degassed magma based on order of magnitude calculations using present-day emission rates and typical volcano lifetimes.  相似文献   

汶川大地震前后GPS观测的精密单历元解得到的震区地壳运动          下载免费PDF全文

顾国华  孟国杰  方颖 《地震学报》2011,33(3):319-326

利用BERNESE软件的单历元观测值双差定位功能,获取了接近2008年5月12日汶川Ms8.0大地震震中5个GPS观测站(PIXI,CHDU,JYAN,NEIJ和LUZH站)震前的短临位移过程及震后短时间的位移.通过拟合和对比分析,讨论了单历元解的精度.计算结果表明,以YANC站为固定站,LUZH站震前5月9日N(南北...  相似文献