Remote sensing and geographic information system (GIS) methods were used for karst research in the coastal area of Northwest Morocco near the city of Safi in order to identify karst landscapes, to describe karst features and to detect geological structures relevant to karst development. The aim of this study was to investigate the use of different satellite data, such as Landsat, RapidEye and IKONOS imagery, as well as ASTER-and SRTM-derived digital elevation models (DEMs) for the analysis of karst features. Dolines were identified by visual interpretations based on high resolution satellite imagery and aerial photographs. Digital image processing of the satellite data, such as deriving vegetation and water index images, helped to identify regions with relatively higher surface water input, where karstification processes might be more intense than in surrounding areas. ArcGIS-integrated weighted overlay tools were used for this purpose as well by aggregating of morphometric, causal factors (lowest and flattest areas) influencing the susceptibility to higher surface water input. Lineament analysis based on the different satellite data contributed to the detection of near-surface fault and fracture zones with potential influence on dissolution processes in sub-terrain waterways.
For civil protection reasons there is a strong need to improve the inventory of areas that are more vulnerable to earthquake ground motions or to earthquake-related secondary effects, such as landslides, liquefaction or soil amplifications. The use of remote sensing and Geographic Information Systems (GIS) methods along with the related geo-databases can assist local and national authorities to be better prepared and organized. Remote sensing and GIS techniques are investigated in north-eastern Greece in order to contribute to the systematic, standardized inventory of those areas that are more susceptible to earthquake ground motions, to earthquake-related secondary effects and to tsunami-waves. Knowing areas with aggregated occurrence of causal (“negative”) factors influencing earthquake shock and, thus, the damage intensity, this knowledge can be integrated into disaster preparedness and mitigation measurements. The evaluation of satellite imageries, digital topographic data and open source geodata contributes to the acquisition of the specific tectonic, geologic and geomorphologic settings influencing local site conditions in an area and, thus, estimate possible damage to be suffered
The quality , data amount and information content of GeoInformation Systems (GIS) dealing with natural hazards and vulnerability assessment has increased considerably during the last decades. Meanwhile many countries have implemented such a GIS for the public use, whereby satellite imageries before and after disasters form important layers within these GIS. In the scope of this research adaptation strategies are developed by presenting an approach in which Geographic Information Systems, used together with remote sensing data, contribute to the analysis and presentation of information, especially required for the increasing geo-hazards in Morocco, such as earthquakes, mass movements and flooding using mainly free available, existing data for contributing to a GIS integrated data base.
ZusammenfassungFolgende Hinweise sprechen fiir die Entstehung der Ringstruktur yon Araguainha in Zentralbrasilien dureh einen kosmisehen Impakt:(1) ein nahezu kreisrunder UmriB, (2) .eine ,,einschtagmorphologische Sequenz", die von innen nach augen aus einer zentralen Erhebung, einen daran angrenzenden Niederungsgiirtel, mehreren Ringwgllen sowie konzentrisehen Brueh-und Sehichtstufen besteht, (8) anstehende Suevite und Triimmerbrekziien, (4) Naehweis der progressiven Stol3wellenmetamorphose in Gesteinsdiinnschliffen, (5) Funde yon ,,shatter cones" und (6) negative Anomalien der magnetisehen Totalintensitiit im Zentrum der Ringstruktur. AbstractThe following facts have supported the origin of the Araguainha circular structure in Central Brazil by a meteoritic impact:(1) the almost circular contour, (2) the impact-morphologic sequence including a central uplift, ring walls and a basin rim of escarpments, (3) outcrops of suevites and mixed breccias, (4) the evidence of shock metamorphism, (5) the presence of shatter cones, and (6) negative anomalies of the total intensity of the magnetic field at the center of the ring structure. ResumenOs fatos seguintes supportam a g6nese da estrutura circular do "Domo de Araguainha"/Brasil Central pot urn impacto de meteoro:(1) a forma circular, (2) a sequSncia morfoldgica de um astroblema, apresentando no nflcleo um soergimento central, cumeadas e eleva,cSes de arranjo anelar e urea borda de euestas da bacia, (3) afloramentos de suevitas et breecias eoloridas, (4) a evid~ncia de metamorflsmo de choque nas laminas das amostras de pedra, (5) a presenca de cones de estilha~amento, e (6) anomalias negativas da intensidade magn6tica de eampo total no eentro da estrutura. The Araguainha Astrobleme/Central Brazil EonezI apycoB Ba~a n }contIenTp}~ec~c~ pacnonoxceHH~ZX paa0-iOMOB PI cnoeB. 3) 3anera}o~}~e p~Ao~ cye~H~Z H oSno~o~H~ze 5pe~n}~. 4) Ycwano~nenne e~e~lo~ yc~a}on~eroc~ ~ewa~opdp~a~a y~apH0f~ Bo~m,z TOHICHX mJnlE1}ax nopoR. 5) i~a~e ,,shatter cones". 6) HerarHBI~aYi aHOMaJIH$I MaI'HHTHOft 05II~e~I HHTeHCHBHOCTH B IIeHTpe ~CO~I~-ReBbZX cTpy~cTyp. KpuTKoe co~ep~aHne
Abstract. The potential contribution of remote sensing and GIS techniques to earthquake hazard analysis was investigated in SW-Haiti in order to improve the systematic, standardized inventory of those areas that are more susceptible to earthquake ground motions or to earthquake related secondary effects such as landslides, liquefaction, soil amplifications, compaction or even tsunami-waves. Geophysical, topographical, geological data and satellite images were collected, processed, and integrated into a spatial database using Geoinformation Systems (GIS) and image processing techniques. The GIS integrated evaluation of satellite imageries, of digital topographic data and of various open-source geodata can contribute to the acquisition of those specific tectonic, geomorphologic/topographic settings influencing local site conditions in Haiti and, thus, to a first data base stock. Using the weighted overlay techniques in GIS susceptibility maps were produced indicating areas where causal factors influencing surface-near earthquake shock occur aggregated and interfering each other and, thus, rise the susceptibility to soil amplification. This approach was used as well to create landslide and flooding susceptibility maps.
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