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1.
《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》2000,25(3):233-237
Since 1977 five tilt-strainmeter stations have been installed in the Friuli seismic area for the detection of tectonic deformations and pre co and post-seismic effects. In 1994 a station for Radon concentration measurements was installed with the aim to detect possible precursors. The noise effect due to rainfalls and atmospheric pressure variations was already stressed in previous papers. In this work the effect of temperature on both tilt measurements and Radon emanation is examined. A significant correlation between tilt and temperature is present on the annual behaviour, mainly due to thermoelastic effects although annual water table level variations can greatly influence the done results. On shorter periods (10–20 days) significant correlations also exist. Regarding the Radon measurements, an interpretative model has been reported. It relates the variation of the correlation coefficient sign with the temperature. Indeed Radon and temperature are positively correlated in winter and inversely correlated during the summer. 相似文献
2.
通过汶川地震震区大量的实地考察已证实沿着早先活动断裂主要发育了两条地表破裂带：一条是沿着映秀－北川断裂产生的逆冲伴随右旋走滑破裂带,长275km,最大垂直位移达11m,水平位移达12m; 另一条纯逆冲性质的破裂带,沿着灌县－安县断裂发育,最大垂直位移达4m。活动断裂之上的地表破裂带是野外工作中确定地震断裂性质的重要现象。另外,在活动断裂相邻区域和远离区域的路面以及建筑体还大量存在变形现象。通常沿活动断裂产生的地表破裂是典型的同震破裂,相邻区域的地表路面及建筑体发育的变形属于次生变形,远离区域发育的变形则属于震后变形。对次生变形和震后变形测量数据的应用容易影响活动断裂特征的确定和性质的判断,因为路面等建筑体上的挤压拱起、叠置以及水平错断等现象多是受到地震过程中通过断裂活动突然释放的巨大能量作用在局部地表建筑体产生的变形。但是,分布广泛的挤压现象暗示了区域上挤压应力场环境,有利于地表同震破裂位置的推测及地震断裂性质的判断。 相似文献
3.
建（构）筑物的变形控制指标 总被引：1，自引：0，他引：1
城市轨道交通和其他市政地下工程建设难免造成周边建（构）筑物的变形,确定建（构）筑物的变形控制指标是进行安全监测和控制的基础。总结目前建（构）筑物控制的各类变形参数,对其定量化研究成果进行归纳,根据收集的大量变形监测资料,划分建（构）筑物的变形损坏等级,对其沉降、差异沉降和倾斜等常规监测项目进行重点分析,并研究了建筑尺寸和变形量、损坏等级的关系。研究结果表明,砂土地层独立柱基的建筑易于产生变形破坏,应防止建筑过量沉降引起的其他变形损坏;建（构）筑物的角变量小于0.002时一般未出现较大影响;建筑尺寸影响变形的大小,应密切关注易于出现变形损坏的多层、高层建筑。 相似文献
4.
Deep-seated gravitational slope deformations and their relationships with tectonic deformation of rocks is considered, to examine the viewpoint of Tectonics as a causative factor in slope deformation.
First, a distinction is made between the different types of deep-seated gravitational slope deformation. Then, the geomorphological and structural effects of the different macrostructural deformations induced by tectonics, on the scale of the whole deforming ridge is briefly discussed. Finally, some case studies that represent either verified or possible cases of gravity deformation in response to tectonic activity are used as illustration. 相似文献
5.
《Geodinamica Acta》2013,26(1-3):49-64
The astronomical and geodetic observatory OCA, located on the karst plateau of Calern (Caussols, France), has been monitoring earth deformation for several years. Two medium baseline tiltmeters have been installed in a shaft in 2007, along with classical hydrogeological monitoring tools in order to investigate the relationship between current karst deformation and hydrology. Dye tests have shown that the plateau is drained towards the East, to the spring of Bramafam, except for its Western third. Karst tilting, as recorded by the tiltmeters, is linked to rainfall events. These instruments bring additional information to characterize different reservoirs: the deep karst aquifer of Bramafan with high amplitude oscillations of its water table, up to 100 m, the perched aquifer of Moustiques shaft whose response is attenuated, and several slope aquifers with reduced oscillations (Fontaniers, Castel Bon Pré). Tilt deformation reaches 8 μad with a definite orientation between N90°E and N100°E. The best correlation between hydrology and tilts is observed for the deep aquifers. If the first autumn rainfall is ineffective on tilt, it recharges the epikarst and refills the reserves. The winter rains cause the water to flush towards the eastern deep aquifer and provokes a quick tilting of the plateau. Finally, the long term variations in tilt and water table show a very good correlation. The relationship between current hydrological deformations and tectonics is also analyzed; broken and shifted speleothems in the shafts indicate a general shift of the plateau towards the south. 相似文献
6.
《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》2000,25(3):271-276
Tilt-strain measurements have been collected since 1977 by several underground stations in the Friuli seismic area (NE Italy) with the aim of detecting seismotectonic deformations. In the work, meteorological effects are initially considered as being able to obscure possible tectonic signals. Two middle-term anomalous signals (tilt and areal strain), not correlated with atmospheric changes, are successively selected for the analysis. They are the strongest and more evident signals recorded in the area after the 1976 destructive seismic events and also are the only two cases of epicentres very near to the recording stations (M = 4.1 and M = 3.9 at 1.8 and 2.9 km, respectively). Evaluations on the basis of micro-cracking and fault creep are carried out. Estimates based on trivial rheological models furnishes crustal viscosity values in agreement with those obtained in the analysis of the silent earthquakes recorded in the same area before the 1976–1977 seismic events. Our data support the hypothesis that prominent precursory signals can be detected only within a distance few times the dimensions of the source area. 相似文献
7.
利用野外露头和镜下薄片等资料、地质统计等方法, 对山东省灵山岛老虎嘴剖面和船厂滑塌剖面软沉积物变形构造分布特征和形成期次进行了研究。船厂剖面发育滑塌褶皱、负载构造、阶梯断层、布丁构造、球—枕构造等典型的软沉积物变形构造;老虎嘴剖面发育层内褶皱、微阶梯断层、层内角砾岩等。根据形成时间、发育部位和形态特征, 将船厂剖面变形划分为滑塌前变形和滑塌中变形, 滑塌前变形又可以细分滑塌体下部变形和滑塌体内部变形。滑塌褶皱具有多级别、多尺度的特点;以厚岩层组成的滑塌褶皱为主, 尺寸为米级;岩层内部纹层形成的次级褶皱为辅, 尺寸为毫米级。滑塌过程中岩层不同部位应力不同, 伴生其他变形构造, 如拉张形成的布丁构造和挤压形成剪切褶皱等。滑塌前已经形成的负载构造等在滑塌过程中保持原来形态, 不因地层变形而变形。这些古地震触发形成的软沉积变形构造证明灵山岛在早白垩世古地震活动频繁。 相似文献
8.
塔里木盆地东南缘新生代构造变形特征研究 总被引：5，自引：1，他引：4
塔里木盆地东南缘新生代变形特征研究对探讨阿尔金构造带新生代的活动特征及阿尔金构造带与西昆仑构造带的相互作用具有重要意义。本文在野外地质调查的基础上,结合地球物理和沉积学资料,探讨了塔里木盆地东南缘的新生代变形及演化特征。塔里木盆地东南缘新生代构造变形受西昆仑构造带、阿尔金构造带和车尔臣断裂带的控制,且变形由西向东减弱。西南部的构造样式主要表现为受西昆仑向北冲断作用控制的冲断构造;东南部为受阿尔金断层走滑作用控制的走滑-冲断构造;而北部则为受车尔臣断层走滑作用控制的基底卷入走滑-冲断构造。中新世,盆地东南缘受西昆仑构造带大规模的冲断活动影响,导致民丰山前盆地挠曲沉降和冲断层发育,而车尔臣断裂仅有微弱活动;上新世开始,构造变形扩展到整个研究区,不仅西昆仑构造带和车尔臣断裂带表现出强烈变形,而且阿尔金断层走滑作用强烈,导致北侧次级断层的强烈走滑冲断作用和若羌山前挤压挠曲盆地的形成。新生代时期,西昆仑构造带北向冲断作用要早于阿尔金构造带的走滑变形,阿尔金构造带的走滑作用对西昆仑构造带北向冲断构造有强烈的改造。 相似文献
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10.
山西清徐县地裂缝灾害现状及类型分析 总被引：3，自引：0，他引：3
研究了山西省清徐县平泉村武家坡村地裂缝地质灾害的现状和主要特征。清徐县平泉村至武家坡村等7个村庄自2002年春天出现地裂缝以来,其灾害呈现日趋加重的趋势,给当地村民的生产及生活带来了极大影响。经过对平泉村至武家坡村地裂缝的现场实地调查,认为清徐县平泉村-武家坡村地裂缝的分布情况复杂,影响带的宽度从3m左右到100多米不等,凡位于地裂缝带内的大部分建筑物都遭到了破坏。地裂缝带内的地面变形形式有陡降型和缓降型两类,其中位于陡降型变形带上的建筑物破坏最为严重。地裂缝引起建筑物的破坏主要有墙体开裂、地面倾斜、地基下沉、楼梯断裂、门窗变形等多种形式。清徐地裂缝目前仍处于活动阶段,这种活动趋势还将持续一段时间,建议地裂缝带内的村民应尽快搬迁,并限制其在地裂缝带内的工程活动,以免造成更大的损失。 相似文献
11.
Based on the USGS slip distribution data (Finite Fault Model), the vector field of the seafloor deformation in the source
of the tsunami that occurred on March 11, 2011, was calculated. The field of seafloor deformation and distribution of depths
in the area of the source were used for reconstruction of the initial elevation of the water surface in the tsunami source.
It was found that the contribution of horizontal deformations into the amplitude of the initial elevation, into the displaced
water volume, and into the potential energy of the initial elevation is at about 20–25%. Within the framework of the linear
theory of long waves, numerical simulation of evolution of the initial elevation was made. The simulation results were compared
to the signals recorded by the four deep water stations DART which were the nearest to the source. It was shown that account
of the horizontal deformation of the seafloor provides a more precise coincidence between the model and real data. Insignificant
differences in arrival times of the model and real signals were interpreted as manifestation of phase dispersion and finite
duration for the seafloor deformation to form. 相似文献
12.
甘肃省永靖县黑方台属于典型的黄土台塬,其黄土具有较强的湿陷性,长期的大水漫灌引起厚层黄土发生严重的湿陷现象,进而诱发滑坡及严重的地面变形。本文以黑方台地表变形为研究对象,采用PS-InSAR技术对2014~2017年期间Sentinel-1 A卫星3条轨道的降轨数据进行处理,得到了不同视线（LOS）方向的变形,进而通过反演和计算得到该地区三维地表形变信息,分析了视线向、垂直向以及水平向的地表变形特征,预测了未来的发展趋势。结果表明:在靠近台塬中部区域以及塬边部分区域的视线向变形速率较大,沉降范围为4~13 mm·a-1;垂向变形较大的区域大都靠近台塬中部,平均变形速率为-20~-6 mm·a-1;整个台面南北向变形很小,平均变形速率为-5~5 mm·a-1,东西向变形较大,平均变形速率大都超过20 mm·a-1。研究区属于不均匀沉降区域;整体来看,研究区的地表变形在短期内仍然处于缓慢加速发展阶段,随着农业灌溉的持续进行,研究区地表变形速率达到一定值后会逐渐下降。 相似文献
13.
通过对滑坡地质环境和变形监测的分析,论述从持续强降雨入渗,经土体饱水软化,到滑动面孕育的滑坡形成机制.并通过数值模拟分析变形破坏前后应力场、变形场和破坏区的分布特征,以深化对滑坡变形破坏特征的认识. 相似文献
14.
Simple monitoring method for precaution of landslides watching tilting and water contents on slopes surface 总被引：2，自引：2，他引：0
Taro Uchimura Ikuo Towhata Trinh Thi Lan Anh Jou Fukuda Carlos J. B. Bautista Lin Wang Ichiro Seko Taro Uchida Akira Matsuoka Yosuke Ito Yuichi Onda Sho Iwagami Min-Seok Kim Naoki Sakai 《Landslides》2010,7(3):351-357
A low-cost and simple monitoring method for early warning of landslides is proposed. To detect abnormal deformation of a slope, this method employs a tilt sensor in place of an extensometer on the slope surface. In order to examine the relevance of measuring rotation angle on a slope surface by tilt sensor, model tests were conducted, and rotation on the slope surface was observed together with slide displacement along the surface. The rotation data responded 30 min before failure in a model test, which could be useful as a signal for early warning. However, the behavior of rotation before failure varies from case to case, and thus, criteria to issue warning should be defined more carefully. For a model slope made of uniform loose sand, measurement of slide displacement along the slope surface is sensitive to failure at the toe, while the measurement of rotation on the slope surface is useful to detect the development of progressive failure upward along the slope. Wireless sensor units with microelectromechanical systems (MEMS) tilt sensor and volumetric water content sensor were also examined on a real slope in Kobe City, and a long-term monitoring was attempted. A simple but possible way to define the criteria of judgment to issue warning can be proposed based on combination of data obtained by the tilt sensors and volumetric water content sensors. 相似文献
15.
《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》2000,25(4):415-420
A small scale experiment with borehole tiltmeters above a gasfield in the Netherlands is described. Pressure variations in the gasfield may cause subsurface deformations leading to tilt. We describe the technique of the installation of the tiltmeters and the influence of the surface conditions on the measurements. For this case study we quantify the minimum pressure variation which is required to result in observable, induced tilt. Tidal tilt observations are shown and used for the verification of the measurements. Finally, we compare the observations with computed ocean tide loading tilt for the M2 tidal component. 相似文献
16.
Displacement patterns of a landslide affected by human activities: insights from ground-based InSAR monitoring 总被引：2，自引：0，他引：2
Francesca Bozzano Ivan Cipriani Paolo Mazzanti Alberto Prestininzi 《Natural Hazards》2011,59(3):1377-1396
Landslides interacting with large infrastructures represent a major problem for the economy, society as a whole, and the safety
of workers. Continuous monitoring for 23 months using an integrated platform with a ground-based SAR interferometer (GB-InSAR),
a weather station, and an automatic camera gave us the opportunity to analyze the response of an unstable slope to the different
phases of work. The deformational behavior of both the natural slope and the man-made structures was recorded and interpreted
in relation to the working stages and the rainfall conditions during the whole monitoring period. A typical pattern of displacement
was identified for shallow landslides, debris produced by the excavation and gabions, metallic walls, and anchored bulkheads.
Furthermore, insights into the dynamics and behavior of the slope and the man-made structures that interact with the landslide
were obtained. Extreme rainfall is the main trigger of shallow landslides and gabion deformations, while anchored bulkheads
are less influenced by rainfalls. Movement of debris that is produced by excavations and temporary metallic barrier deformation
are closely related to each other. The herein proposed monitoring platform is very efficient in monitoring unstable slopes
that are affected by human activities. Moreover, the recorded patterns of displacement in the slope and the man-made structures
can be used as reference data for similar studies and engineering designs. 相似文献
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循环加卸载下花岗岩非均匀变形演化的声发射特征试验研究 总被引：1，自引：0，他引：1
为了研究岩石材料在循环加卸载过程中的声发射特征与非均匀变形的对应关系,开展了花岗岩试件单轴循环加卸载试验。利用声发射系统和CCD相机分别对试样变形破坏过程中的声发射信号和试件表面的变形图像进行采集,结合数字散斑相关方法,对试件非均匀变形演化过程中的声发射特性进行研究。研究结果发现：每次循环加载过程中,非均匀变形的最小点皆与应力卸载的最低点相对应。而自局部化带启动后,每次循环加载过程中的非均匀变形的最大点滞后于循环加载应力的顶点。非均匀变形演化与声发射信号存在较好的对应关系,循环加载过程中非均匀变形的首次转折增大点对应声发射信号增加的起点,非均匀变形的最大点对应声发射信号平静期的起点。随循环次数增加,非均匀变形程度与Felicity比呈负相关关系,即非均匀变形越大,损伤程度越大,Felicity比越小。 相似文献
20.
歪石砬子变粒岩构造演化序列 总被引：4，自引：1，他引：3
歪石砬子变粒岩为早元古代变质岩,因经历了多期变形的叠加与改造,岩石构造非常复杂,可划分为四期变形,由区域变质变形,层间韧性剪切带,开阔褶皱和单向膝折带组成构造演化序列,前两期变形属中浅部构造层次变形,后两期变形属表浅部构造层次变形;构造应力场由近南北向挤压转为近东西向挤压。 相似文献