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1.
The western part of the Argentera–Mercantour massif (French Alps) hosts very large currently active landslides responsible of many disorders and risks to the highly touristic valleys of the Mercantour National Park and skiing resorts. A regional scale mapping of gravitational deformations has been compared to the main geo-structures of the massif. A relative chronology of the events has been established and locally compared to absolute 10Be dating obtained from previous studies. Two types of large slope destabilisations were identified as follows: deep-seated landslides (DSL) that correspond to rock volumes bounded by a failure surface, and deep-seated gravitational slope deformations (DSGSD) defined as large sagging zones including gravitation landforms such as trenches and scarps or counterscarps. Gravitational landforms are mainly collinear to major N140°E and N020°E tectonic faults, and the most developed DSGSD are located in areas where the slope direction is comparable to the orientation of faults. DSL are mostly included within DSGSD zones and located at the slopes foot. Most of DSL followed a similar failure evolution process according to postglacial over steepened topographies and resulting from a progressive failure growing from the foot to the top of the DSGSD that lasts over a 10 ky time period. This massif-scale approach shows that large-scale DSGSD had a peak of activity from the end of the last deglaciation, to approximately 7000 years bp. Both morphologic and tectonic controls can be invoked to explain the gravitational behaviour of the massif slopes. 相似文献
2.
黄土构造节理研究及其应用 总被引：7，自引：2，他引：7
作者发现大量不同力学性质的黄土构造节理后，识别了它们的区域性、系统性特征；认定其两组扭裂面代表新构造应力场最大剪切应力方向，利用黄土构造节理系及由其控制的土层沟槽网络恢复了相应地区Q3-4构造应力场；提出构造节理是黄土区地下水运移的主要通道和赋存的场所；发现构造节理是黄土区地裂缝、滑坡、崩塌和水土流失等地质灾害的构造基础之一，证实构造节理是黄土地层的软弱面，风化和继之而来的应力侵蚀就由此开始，进而逐步塑造黄土碟、穴、井、桥、柱、墙、沟等潜蚀地貌和部分侵蚀地貌。研究黄土构造节理对恢复新构造应力场、帮助预测地裂乃至地震活动、控制水土流失和滑塌灾害、进行工程乃至区域稳定性评价、重新认识黄土潜蚀地貌发育规律、指导干旱半干旱黄土区找水，既有理论意义又有实际意义。 相似文献
3.
Y. Ota Dr. 《GeoJournal》1980,4(2):111-124
The study of tectonic landforms is one of the main themes of geomophological research in Japan, characterized as a tectonically active area along the subducting oceanic plates. The recent trends in the studies of tectonic landforms which include an arrangement or distribution of major ranges and plains, vertical displacement of low-relief erosion surfaces and of marine terraces, and various kinds of deformed features due to active faulting or folding, are introduced here with special reference to the Quaternary geomorphic development. A regionality of each tectonic landforms is also summarized. Further, some fundamental concept of the Quaternary tectonics, for instance, an accumulative character of each type of deformation and sequence of rate of tectonic movement, reconstruction of former stress field as well as a relation between the Quaternary tectonic movement and seismic deformation in present and historic time are discussed on the basis of analysis of the tectonic landforms. The Quaternary tectonics of the Japanese Islands are essentially characterized by the compressional stress, originated from the subduction of oceanic plates, and regionality can be interpreted as the result of the different response of each tectonic region to island arc tectonics. 相似文献
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Livio F. A. Zerboni A. Ferrario M. F. Mariani G. S. Martinelli E. Amit R. 《Landslides》2022,19(8):1825-1841
Triggering mechanisms and causative processes of deep-seated gravitational slope deformations (DSGSD) in Alpine and high mountain areas include, among others, post-glacial de-buttressing, earthquake-induced ground shaking, or co-seismic surface faulting. Distinguishing between climatic or tectonically driven factors is challenging since faults and fracture systems can play both an active and/or passive role in the process initiation. We applied an integrated approach, including morpho-structural analysis, geologic field survey, a paleoseismological approach applied to trenching, radiocarbon dating and detailed sedimentological analysis, to a DSGSD located in the Cavargna Valley (N Italy), an area that was never occupied by extensive ice tongues in the Upper Pleistocene and Holocene. We were able to document at least two phases of movement from the Middle Holocene onwards and related triggering factors. Thanks to the comparison with dated lacustrine turbidites in the Alpine Lakes, we argue a seismic triggering for the landslide onset, with a possible source located in southern Switzerland, close to the Insubric Line. The later evolution of the landslide was instead driven by climatic predisposing conditions (humid and cold), instead, corresponding to a phase of enhanced slope instability.
相似文献6.
Mohammed Zia Kanika Sharma Arun Kumar Saraf Josodhir Das Suman Baral Mrinmoy Das 《Natural Hazards》2014,71(3):1379-1388
The central Kutch region of Gujarat, India, experienced a M7.7 earthquake on January 26, 2001, causing large-scale ground deformations including a huge loss of lives and infrastructure. The rupture of a hidden reverse fault was the reason for this intense tectonic activity. The post-seismic ground deformations, attributed to the relaxation phase of a stressed crustal layer, have been analyzed using a pair of Advanced Land Observation Satellite-Phased Array type L-band Synthetic Aperture Radar interferometric synthetic aperture radar (InSAR) images. The InSAR images were obtained in 2007 and 2010, covering an area around Bhuj. It falls on the Kutch Mainland Fault and Katrol Bhuj Fault. Using the ADORE-DORIS software, interferometric imagery has successfully been generated, covering the study area. This allowed making interesting geological inferences. Three different regions in the study area elicited countable visible colored fringes, indicating different amounts of positive and negative ground deformations (surface motion with respect to the satellite). They occurred within the InSAR data acquisition dates. The region around Bhuj and to the north and east of Bhuj showed top surface deformations of about 35, 35, and 24 cm, respectively. The synoptic view of the interferometric image of the study area suggests two crustal fault lines running to the north and south of Bhuj city. The Institute of Seismological Research, geophysical and Global Positioning System data, indicates that huge seismic events occurred during the year 2007–2010 and supports the observational inference of clustering of interferometric fringes to the E and NE of the study area. 相似文献
7.
Control of slope deformations in high seismic area: Results from the Gulf of Corinth observatory site (Greece) 总被引：1，自引：0，他引：1
The northern coast of the Peloponnesus (Greece) is characterized by high seismic activity related to the Gulf of Corinth opening with an extension rate of 16 mm y− 1. Studies presented in this paper focus on the characterization of links between tectonic and slope deformations on the Panagopoula slope, located on the southern coast. The approach is centred on qualitative and quantitative data acquisition based on geological and geomorphological investigations, geophysical imagery by electrical resistivity tomography and slope displacement monitoring.Firstly, we highlight two different types of slope deformation on Panagopoula: a superficial landslide affecting weathered limestone, and a large-scale deformation without global failure expressed in the field. Tectonic features play a major role in these two dynamic processes, taking into account the strong geometrical link between the inherited fractures and gravitational scarps mapped in the field.Secondly, the displacements survey network, distributed on both sides of a significant fault crossing the slope, allows the quantification of slope displacements underlying two components: (i) a gravitational sliding (N010) along the slope, and (ii) a supposed tectonic component (N240). 相似文献
8.
《Geodinamica Acta》1999,12(2):71-80
In the Maghreb, the southern border of the Kabylie (Algeria) mountains is considered as an aseismic region. The detailed study of the historical seismicity of this region shows moderate seismic activity (M1 = 5.0) which is not coherent with the observed tectonic deformations. However, an analysis of the morphology on Landsat image, aerial photos and the topography shows Quaternary deformations in the southern side of the “Kabylie massifs” (Algeria). These deformations are interpreted as reactivation of Miocene thrust faults. The tectonic Quaternary scarps are more spectacular in the Bouira and Tazmalt region and might be associated with successive strong earthquakes (M = 7.0). Therefore, this major active thrust fault observed in this region, as in many intraplate regions, poses the problem of the long return period of seismic activity in this zone. © Elsevier, Paris 相似文献
9.
Bondur V. G. Garagash I. A. Gokhberg M. B. Lapshin V. M. Nechaev Yu. V. 《Doklady Earth Sciences》2010,430(1):147-150
A three-dimensional geomechanical model of Southern California, including mountain relief, fault tectonics, and characteristic
internal borders, such as the roof of the consolidated crust and Moho surface, was created. The initial stress state of the
model is determined by the gravitational force and horizontal tectonic movement, established on basis of GPS observations.
Monitoring of variations in the stress state of the Earth’s crust and lithosphere, which are generated by seismic processes,
has shown that the model enables us to predict an increase of seismic activity in a region and to mark the places in which
average earthquakes can occur in the following two weeks. 相似文献
10.
东营凹陷盐-泥构造的样式和成因机制分析 总被引：8，自引：0，他引：8
以地震剖面的精细解释为基础,借鉴典型盐或泥构造的研究成果,文中确立了东营凹陷盐-泥构造样式:盐-泥枕构造、盐-泥滚—滑脱断层簇—滚动背斜构造、盐-泥核背斜—拱顶断层簇构造。区域伸展作用下的重力滑动作用是东营凹陷盐-泥构造的主导成因机制。重力滑动作用表现为触发盐-泥层的聚集—隆升和引起薄皮滑脱作用。由此文中将盐-泥构造演化历程划分为盐-泥枕发育期和滑脱断层—盐-泥滚—盐-泥核背斜发育期。最终建立了东营凹陷盐-泥构造的成因-演化模式。 相似文献
11.
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
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This paper highlights the seismic microzonation carried out for a nuclear power plant site. Nuclear power plants are considered to be one of the most important and critical structures designed to withstand all natural disasters. Seismic microzonation is a process of demarcating a region into individual areas having different levels of various seismic hazards. This will help in identifying regions having high seismic hazard which is vital for engineering design and land-use planning. The main objective of this paper is to carry out the seismic microzonation of a nuclear power plant site situated in the east coast of South India, based on the spatial distribution of the hazard index value. The hazard index represents the consolidated effect of all major earthquake hazards and hazard influencing parameters. The present work will provide new directions for assessing the seismic hazards of new power plant sites in the country. Major seismic hazards considered for the evaluation of the hazard index are (1) intensity of ground shaking at bedrock, (2) site amplification, (3) liquefaction potential and (4) the predominant frequency of the earthquake motion at the surface. The intensity of ground shaking in terms of peak horizontal acceleration (PHA) was estimated for the study area using both deterministic and probabilistic approaches with logic tree methodology. The site characterization of the study area has been carried out using the multichannel analysis of surface waves test and available borehole data. One-dimensional ground response analysis was carried out at major locations within the study area for evaluating PHA and spectral accelerations at the ground surface. Based on the standard penetration test data, deterministic as well as probabilistic liquefaction hazard analysis has been carried out for the entire study area. Finally, all the major earthquake hazards estimated above, and other significant parameters representing local geology were integrated using the analytic hierarchy process and hazard index map for the study area was prepared. Maps showing the spatial variation of seismic hazards (intensity of ground shaking, liquefaction potential and predominant frequency) and hazard index are presented in this work. 相似文献
14.
Maria A. Zoran Roxana S. Savastru Dan M. Savastru 《Central European Journal of Geosciences》2014,6(2):195-206
Cumulative stress energy in active seismic regions caused by tectonic forces creates various earthquake precursors. This energy transformation may result in enhanced transient thermal infrared (TIR) emission, which can be detected through satellites equipped with thermal sensors like MODIS (Terra/Aqua) and AVHRR (NOAA). Satellite time-series data, coupled with ground based observations, where available, can enable scientists to survey pre-earthquake signals in the areas of strong tectonic activity. This paper presents observations made using time series MODIS and NOAA-AVHRR satellite data for derived multi-parameters including land surface temperature (LST), outgoing long-wave radiation (OLR), and mean air temperature (AT) for the moderate, 5.9 magnitude earthquake, which took place on the 27th of October, 2004, inthe seismic region of Vrancea, in Romania. Anomalous thermal infrared signals, reflected by a rise of several degrees celsius (°C) in LSTs, and higher OLR values were seen several days before the earthquake. AT values in the epicentral area also increased almost two days prior to the earthquake and intensified three days after the main shock. Increases in LSTs and OLR disappeared three days after the main shock. The survey and joint analysis of geospatial and in-situ geophysical information on land surface temperatures and outgoing long-wave radiation provides new insights into the field of seismic hazard assessment in Vrancea, a significant area of tectonic activity in Romania and Europe. 相似文献
15.
Farshid Vahedifard Christopher L. Meehan 《Geotechnical and Geological Engineering》2011,29(6):1023-1034
Predictive displacement-based methods provide a useful index of the seismic performance of earth dams and embankments and
can be used in preliminary assessments of these structures. In practice, simplified Newmark-type sliding block methods are
commonly used for this purpose. Using a database of 122 previously published case histories of permanent deformations of earth
dams and embankments, the performance of six simplified sliding block models was examined. The results show that all six simplified
methods underpredict seismic displacement for many of the embankment and earth dam cases that were examined, sometimes by
a significant amount. An empirical correlation was developed by performing linear multiple regression analysis utilizing multiple
slope and ground motion input parameters. This approach is believed to more properly reflect strong ground motion characteristics
than the use of a single ground motion parameter such as the peak ground acceleration, the approach that has been previously
employed in other correlations of this type. After exploring numerous functional forms, the final resulting seismic displacement
correlation that was proposed was determined to be a function of the critical acceleration, the critical acceleration ratio,
the slope height, the peak ground acceleration, the peak ground velocity, the spectral acceleration, and the predominant period
of earthquake shaking. The proposed empirical equation yields better correlation with the case history database than does
other existing empirical correlations or simplified sliding block models. 相似文献
16.
One of the most critical lessons of the recent earthquakes is the need for seismic planning for lifelines, with appropriate
supplies and back up systems for emergency repair and restoration. Seismic planning, however requires physical loss estimations
before the earthquakes occur. Buried pipeline damage correlations are critical part of loss estimation procedures applied
to lifelines for future earthquakes. We review the existing pipeline damage relationships only for ground shaking (transient
ground deformations) in the light of recent developments and evaluate them with Denizli City, Turkey water supply system.
Eight scenario earthquakes with four different earthquake magnitudes between M6 and M7 caused by two different fault ruptures (Pamukkale and Karakova-Akhan Faults) were used. Analyses were performed by using
Geographical Information Systems (GIS). This high number of different scenario earthquakes made it possible to compare the
pipeline damage relationships at different ground shaking levels. Pipeline damage estimations for Denizli City were calculated
for each damage relationship and earthquake scenario. Relative effects of damage relationships and scenario earthquakes on
the results were compared and discussed. The results were presented separately for brittle, ductile, and all pipelines. It
was shown that the variation in ductile pipeline damage estimations by various relationships was higher than the variation
in brittle pipeline damage estimations for a particular scenario earthquake. 相似文献
17.
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
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19.
2008年MS 8.0级汶川大地震发生在具有复杂的地质构造背景、强烈的地表起伏、不均匀的弹性和黏性结构的龙门山断裂带上。由于震前地震活动性不够强烈且地表构造变形较小,龙门山断裂带的地震危险性在汶川地震之前被低估。从数值模拟的角度,建立黏弹性有限元模型,考虑了初始地形、重力、构造加载、黏弹性松弛等因素对2008年汶川大地震的孕震、同震及震后150年变形全过程的影响,定量研究了映秀-北川断裂带的同震及震后变形,分析了弹性层、黏弹性层的应力积累、释放、调整的特点,模拟得到地表同震和震后位移与大地测量资料较为吻合,对汶川大地震的余震分布进行了力学上的解释,模拟得到震前、同震及震后的应力变化有助于深入分析大地震的动力学成因及其对周围区域的地震危险性影响。 相似文献
20.
E. A. Rogozhin 《Geotectonics》2012,46(5):369-378
The September 24, 1999 Ahram Earthquake in southwestern Iran was moderate in energy (M = 5.0–5.5 from different sources) and did not entail significant destruction and casualities. The tectonic position of the source zone, surficial seismic dislocations, and results of macroseismic and seismological study of this seismic event in the junction zone of the Zagros Fold System and the piedmont plain are described in the paper, including data on rejuvenated ancient ruptures exposed in two trenches excavated across the strike of the regional Kazerun-Borazjan Fault. One of the trenches was driven a few months before and the other a year after this seismic event. The conclusion is drawn that new deformations in the Quaternary near-surface sediments observed at the walls of both trenches may be regarded as unusual seismic ruptures of the Ahram earthquake. These ruptures, described as proved primary seismic dislocations of such a moderate seismic event, are a unique phenomenon in the world seismotectonic practice. The localization of the earthquake source zone in the Kazerun-Borazjan Fault Zone with complex kinematics makes it possible to study the internal structure of one of the most important tectonic lines of the Zagros Fold Region. 相似文献