Integrated Use of Optical and Radar Satellite Data for Active Faults and Corresponding Displaced Landforms in Kozani Basin (Greece)

Abstract

The usefulness of integration of SAR (ERS-1) and Landsat TM data for study active faults and the corresponding displaced landforms in flat or almost flat areas has been demonstrated. The study area is the Kozani basin which in May 13, 1995 was affected by a strong earthquake (Ms=6.6). After co-registration and resampling the two data sets were merged to form a combined image. The combined image offers the spectral characteristics of the TM data with the spatial resolution and roughness sensitivity of SAR images. The merging method used was the IMS to RGB transform. The criteria and parameters examined were geomorphic features, drainage network analysis, slope processes, terrain analysis, and observations on spatial distribution of soil cover as well as linear features that correspond to fracture zones crossing the basin. The use of the combined image allowed us to identify tectonic terraces in the basin produced by activity of normal faults located in the adjacent relief zone.     

黔西南地区遥感构造与金矿的关系及找矿预测

遥感图像显示黔西南地区有两个地层区——台地相区和槽盆相区。复合内生微细浸染型金矿均产于短轴背斜、穹窿和与之伴生的断裂内,因此遥感解译的正向环形构造和环形影像对找矿有重要意义。另外,区内金矿与遥感解译推测的隐伏断裂也有一定关系。基于上述认识,以ETM+和GeoEye数据为数据源生成融合图像,进行遥感构造解译和分析,圈定了金矿找矿预测区,为进一步开展贵州省矿产资源潜力评价和找矿工作提供了参考依据。     

渭河盆地深大断裂处构造应力特征及其活动特性

利用渭河盆地2001~2010年高精度GPS监测资料,采用有限元数值分析法,分析了渭河盆地内深大断裂处的构造应力特征及断裂活动特性。结果表明,盆地西部断裂处均呈现出明显的近E-W（east-west）向挤压应力特征,而盆地中部断裂处则均呈现出显著的NW-SE（northwest-southeast）向拉张应力特征,东部断裂处呈现出一定的NW-SE向拉张应力,但该部量值较中部断裂处小;走向各异的同一条深大断裂不同区段,呈现出的应力特征、量值以及活动速率也存在差异性;跨断裂剖线显示沿断裂走向的速度分量在断裂两侧均发生了一定量值的变化,构造断裂具有一定的扭动特性。模拟计算结果进一步显示盆地中部较东、西部受NW-SE向拉张应力作用显著,且在中部这些具有拉张应力特征的深大断裂交汇处,特别是断裂活动速率较大的区段,正是盆地内地裂缝灾害最为集中发育的区域。     

热红外遥感浙江地表热环境分布研究

全球气候变暖与人类戚戚相关,研究发现不仅是城市的热岛效应引起了局部区域的地表热环境分布差异,很多地质构造、岩性、土壤、植被等地质及自然地理因素也有影响。本研究选取浙江省作为研究区,利用Landsat 8 OLI/TIRS遥感影像反演地表温度,分析冬季地表热环境分布及其影响因子。结果表明,断裂带附近地表热环境受到断裂带分布影响;岩石和土壤通过不同的地表覆被类型影响地表温度。地表热环境分布与断裂带等自然因素存在一定相关性。     

内蒙古巴彦塔拉盆地构造与铀矿化的遥感地质研究

通过TM数据假彩色合成、纹理分析、目视解译及隐伏信息提取等手段,解译了内蒙古巴彦塔拉盆地内铀矿找矿目标层(K₁b)出露范围,解译并野外追索了NE向的控盆断裂组(F₁、F₂、F₃)、NNE向断裂组(F₂₀、F₂₁)以及NW、近EW向断裂组,通过对古河道、现代地貌水系的分析,总结了区内新构造运动的特点;通过热辐射信息、植被信息的提取,分析了地下水补-径-排的特点和铀矿化的关系。     

融合多元遥感信息的新右江次级活动断裂解译

提出了融合多光谱影像、全色影像、DEM等多元遥感信息的断裂特征增强方法,建立了以地形和水体的空间特征变化为基础的断裂解译标志,解译并发现桂西北巴马-马山断裂带和右江断裂带之间存在一条北西向展布、长约40km的新的右江次级活动断裂,结合野外地震地质调查进行了验证。多元遥感信息融合处理中,将KL变换、HIS变换、乘积变换、比值变换、小波变换等融合方法进行了全面比较,对融合后影像进行主分量分析,确定了乘积变换融合的影像增强方法和解译底图,显著突出了活动断裂特征。     

重大工程场址地震地质环境评价中遥感应用

本文主要探讨了重大工程场址区地震地质环境评价中遥感应用方法,并介绍了遥感在珠海伶仃洋跨海大桥工程场址地震地质环境评价中的实际应用。     

Liquefaction Identification Using IRS-1D Temporal Indices Data

One of the major after effect of Bhuj Earthquake which occurred on January 26, 2001 was wide spread appearance of liquefaction of soil in the Rann of Kachchh and the coastal areas of Kandla port covering an area of more than tens of thousands of kilometers. Remote sensing data products allow us to explore the land surface parameters at different spatial scales. In this work, an attempt has been made to identify the liquefied soil area using conventional indices from IRS-1D temporal images. The same has been investigated and compared with Class Based Sensor Independent (CBSI) spectral indices, while applying fuzzy based noise classification as soft computing approach using supervised classification. Seven spectral indices have been investigated to identify liquefied soil areas using temporal multi-spectral images. The result shows that the temporal variations can be accounted by using appropriate remote sensing based spectral indices. It is found that CBSI based TNDVI using temporal data yields the best results for identification of liquefied soil areas, while CBSI based SR gives best results for water body identification.     

基于遥感技术的祖厉河流域LUCC与蒸散发研究

本文以陇中黄土高原的祖厉河流域为研究区,基于Landsat系列遥感影像,利用主成分变换方法,与地面温度和植被指数相结合,进行土地利用/土地覆盖提取研究,在此基础上,探讨祖厉河流域土地利用/土地覆盖变化(LUCC)及其驱动因素。利用基于TM影像的SEBAL(Surface Energy Balance Algorithm for Land)模型,从祖厉河流域三期影像提取了区域蒸散发通量。首先进行了NDVI、比辐射率和地面温度等地表参数的计算,然后反演了地表的净辐射、土壤热通量和感热通量,根据能量守恒最终获得日蒸散发量。结合气象观测数据反演作物系数,最后计算月蒸散发量。对同期的土地利用/土地覆盖数据和陆面蒸散发量进行对比分析,探讨了土地利用类型的变化对流域内能量和水分时空分异的影响。     

Geological study of sedimentary basins using SPOT data

This paper illustrates the benefits of DTMs created from SPOT images for the exploration of sedimentary basins. We chose an example located in the Ebro sedimentary basin in Spain, characterized by good outcropping conditions and slight deformations. The data used consist of a pair of SPOT panchromatic images and a SPOT XS image. The work consists of making up a 3D database, followed by interpretation of stereo pairs computed from orthoimages and the DTM. This interpretation is made on a stereoscopic desk and results in a digital file containing in the form of vectors all the observed faults and lithology. These vectors are then used to make calculations on the geometry of the objects they represent: we demonstrate that we can accurately measure layer directions and dips, sediment thicknesses and fault throws. Synthesis of perspective views made at the same time provide a good understanding of the structures and help to test their geometric consistency. Thus knowledge about relief given by DTMs helps to interpret remote detection images in 3D space, and particularly to accurately quantify the results of this interpretation.     

南水北调西线工程区活动断裂构造遥感研究

根据断裂构造的判读标志,在南水北调西线工程区共存在NW,NE,SN和EW向四组断裂近200条,NW向断裂为区域性的断裂构造,控制工程区地貌、水系等的发育。其中,有22条断裂规模较大,对输水线路存在相对较大的影响。野外考察结果表明,区内有5条全新世时期的活动断裂和12条晚更新世时期的主干和区域性大断裂。通过综合分析发现,5条全新世时期的活动断裂因为离输水线路较远或未穿越输水线路,而12条晚更新世时期的断裂构造则因全新世以来没有活动,因而它们对工程区的影响总体上还是有限的,工程区处于一个相对稳定的区域,而区域构造分析的结果也说明工程区位于一个相对的安全岛内。     

全球热带森林分布区NPP变化及其气候响应分析

本文基于MODIS遥感数据,利用掩膜分析提取了研究区的NNP数据;并结合气象因子数据,利用地理信息技术及数学统计方法,对比分析了2001—2013年全球3个主要热带森林分布区森林NPP变化及其气候响应的异同。结果表明,研究区NPP总量整体呈减少趋势。对比3个区域NPP与温度、降水和光合有效辐射(PAR)的相关关系,亚马孙流域研究区和刚果河流域研究区NPP对PAR变化更为敏感,东南亚研究区NPP对降水变化更为敏感;东南亚研究区NPP对气候变化响应的敏感性较高,刚果河流域研究区次之,亚马孙流域研究区最低。该研究对于进一步了解全球热带森林变化与气候的相关关系具有一定的参考价值。     

基于GNSS/InSAR/GIS的活动断层地震危险性评估系统

本文从GNSS、InSAR、重力、水准等多种大地测量资料联合确定活动断层地壳形变、应变和应力,以及与GIS相结合的角度出发,讨论了基于库仑破裂准则的活动断层地震危险性评估方法,系统阐述了活动断层地震危险性评估系统的设计。该系统主要利用各种大地测量数据联合确定活动断层区域的位移场,反演计算应变场、应力场、活动断层运动参数以及库仑应力;通过确定活动断层的临界应力值,建立地震危险性评估模型,评估可能发生地震的位置、最大震级、复发时间及其对应的概率;最后借助GIS实现断层区域的地质和构造环境、三维形变数据、应变场、应力场和地震危险性综合评价图的管理与可视化。本文最后讨论了所建系统的具体应用,讨论了汶川地震激发的同震静态库仑应力、应力扰动的持续时间和龙门山地区的地震活动率。     

Morphotectonic analysis in Anandpur Sahib area,Punjab (India) using remote sensing and gis approach

Anandpur Sahib area of Rupnagar district (Punjab) was investigated using an integrated multi-disciplinary approach of geomorphological, structural, drainage and morphotectonic analysis through satellite data and GIS. Most commonly used geomorphic indices viz., channel sinuosity, drainage basin asymmetry, basin elongation ratio, mountain front sinuosity and valley floor to valley width ratio index have been used to identify the geomorphic indicators of active tectonics in the area. Existence of fluvial anomalies viz., abrupt changes in flow direction, flow against gradient, beheaded streams and river terraces reflect the strong structural control on the fluvial features. Asymmetric nature of drainage basin, elongated nature of the sub-watersheds, straight to curvilinear mountain fronts and narrow incised valley floors further substantiate the role of active tectonics in the region.     

Subsidence in the Kathmandu Basin,before and after the 2015 Mw 7.8 Gorkha Earthquake,Nepal Revealed from Small Baseline Subset-DInSAR Analysis

Land subsidence in densely urbanized areas is a global problem that is primarily caused by excessive groundwater withdrawal. The Kathmandu Basin is one such area where subsidence due to groundwater depletion has been a major problem in recent years. Moreover, on 25 April 2015, this basin experienced large crustal movements caused by the Gorkha earthquake (Mw 7.8). Consequently, the effects of earthquake-induced deformation could affect the temporal and spatial nature of anthropogenic subsidence in the basin. However, this effect has not yet been fully studied. In this paper, we applied the SBAS-DInSAR technique to estimate the spatiotemporal displacement of land subsidence in the Kathmandu Basin before and after the Gorkha earthquake, using 16 ALOS-1 Phased Array L-band Synthetic Aperture Radar (PALSAR) images during the pre-seismic period and 26 Sentinel-1 A/B SAR images during the pre- and post-seismic periods. The results showed that the mean subsidence rate in the central part of the basin was about ?8.2 cm/year before the earthquake. The spatial extents of the subsiding areas were well-correlated with the spatial distributions of the compressible clay layers in the basin. We infer from time-series InSAR analysis that subsidence in the Kathmandu basin could be associated with fluvio-lacustrine (clay) deposits and local hydrogeological conditions. However, after the mainshock, the subsidence rate significantly increased to ?15 and ?12 cm/year during early post-seismic (108 days) and post-seismic (2015–2016) period, respectively. Based on a spatial analysis of the subsidence rate map, the entire basin uplifted during the co-seismic period has started to subside and become stable during the early-post-seismic period. This is because of the elastic rebound of co-seismic deformation. However, interestingly, the localized areas show increased subsidence rates during both the early-post- and post-seismic periods. Therefore, we believe that the large co-seismic deformation experienced in this basin might induce the local subsidence to increase in rate, caused by oscillations of the water table level in the clay layer.     

Spatial-temporal changes of NDVI and their relations with precipitation and temperature in Yangtze River basin from 1981 to 2001

Multitemporal NOAA/AVHRR NDVI images and monthly temperature and precipitation data were obtained across Yangtze River basin covering the period 1981–2001. The spatial and temporal patterns of NDVI are the same, while spatial analysis shows that the NDVI is influenced by the vegetation types growing in the study regions, and NDVI presents an increasing trend during the study period in the whole basin. The climate indicators play an important role in the changes of vegetation cover in the river basin. In the two Indicators, temperature has a significant effect on the NDVI values than precipitation in the whole basin. However, in the 11 subbasins, the different rules are shown in different subbasins.     

Lineaments and seismicity of Kerala — a remote sensing based analysis

Seismically active lineaments of Kerala State were identified by correlating the lineaments mapped using IRS LISS-I data with the earthquake occurrences. There are 31 earthquake incidences in Kerala since 1821, out of which 22 are falling on/close to 9 major lineaments/faults (length more than 20 km) indicating the possible correlation between lineaments/faults and earthquakes. It was observed that the earthquake occurrences are mostly associated with the NNW-SSE to NW-SE trending lineaments (6 out of 9 lineaments), which are considered to be formed sympathetic to the West Coast Fault. Hence, there is a need to monitor these seismically active lineaments using advanced techniques such as GPS, SAR Interferometry etc. for better understanding of the influence of these lineaments on the seismic activities of Kerala.     

辽河盆地及其邻区遥感图像的石油地质分析

通过对不同种类、不同波段及不同处理方法所获得图像的分析表明, 一种卫片组合图像处理 方法, 即线性拉伸-直方圆调整-局部增强-彩色级上色所产生的图像, 对了解辽河盆地前第三 系基底起伏状况及其结构特点具有良好效果。 地质解译分析肯定了北东(含北北东)向线性构造的主导作用, 但同时遥感信息强烈地反映 了北西向线性构造对盆地构造格架的影响。地质解译还表明, 辽河盆地的环形影像具有两个明显 特点:(1)浅色影像以反映正向构造为主;(2)深色影像以反映负向构造为主, 而已知油田在 标准假彩色图像上也具有明亮的浅色圆形或块状影像特征。因此, 可结合其它地质资料的综合分 析, 以类比方法来预测新的油气田。     

Morphometric analysis of a drainage basin using aerial photographs: A case study of Khairkuli basin,district Dehradun,U.P.

Remote sensing techniques using satellite images and aerial photographs are convenient tools in morphometric analysis of a drainage basin. In the present study morphometric parameters of Khairkuli drainage basin, district Dehradun, are worked out using aerial photographs. The parameters worked out include bifurcation ratio, stream length, form factor, circulatory ratio, elongation ratio, drainage density, constant of channel maintenance and stream frequency. Hypsometric relations of drainage basin are also presented. Relation between cumulative stream length and the stream order establishes that the ratio between cumulative stream length Σ ₁ ^u Σ ₁ ^nu Lu and the stream order u is constant throughout the. successive orders of a drainage basin suggesting that geometrical similarity is preserved in the basins of increasing order. The morphometric parameters computed suggest that the area is covered by resistant permeable rocks (with fracture and karstic porosities) and vegetative cover, the drainage network is affected by tectonic disturbances. The peak flows generated from the basin are likely to be moderately high and of short duration.