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It is known that many of the geo-hazards that ever happened on our planet are located in active zones. So it is of most important to obtain detailed information on regional structures.
Remote sensing and GIS have been brought forward for many years, and have applications in many hazard reduction domains, such as Earthquakes monitoring. Remote sensing and GIS techniques have been thought as a good complementary tools to map active zones quickly at a large scale.
In this paper, an effective methodologies are going to be presented in order to identify geo-hazard zones from different sources of Remote Sensing images and Geographic Information System. First, comparing the capability of some satellite sensors in hazardous zones survey. Then, discussing a few digital image processing approaches used for information enhancement and feature extraction related to active zones. Those methodologies include band ratio, Principal Components Analysis, , filtering and texture statistics. The experimental results showed that Remote Sensing multi-spectral images have great potentials in large scale active zones investigation. Earthquake mitigation can be achieved with a better knowledge of a region's infra-and substructures. The study area, AL Hammad Basin Southeast of Syria is tectonically active and subjected to numerous seismic activities indicating that these sites are active within a continual faulting movement. The experimental results show that multi-spectral images have great potentials in large scale active faults investigation. It has also got satisfied results when deal with invisible faults. Active Faults have distinct features in satellite images. Usually, there are obvious straight lines, circular structures and other distinct patterns along the faults locations. Remotely sensed images Landsat ETM , SPOT XS/PAN have been used in these active faults mapping.
The study shows that the Moderate and High resolution satellite images are the best choice, because in low resolution images, the fault features did not be visible in most cases. In addition to that, digital image processing, statistical analysis of ETM data features from a DEM produced from SAR interferometry show the existence of spectral structures at the same sites. The extraction of details from satellite imagery depended on the spectral contrast between the object and its surroundings. Lineaments reflecting the regional tectonic trend were all clearly displayed on the ETM imagery as straight to curvilinear topographic breaks. It was found that terrain elements were, in general, more readily distinguished on the radar imagery than with SPOT-XS data. It has shown that a radar image can make a significant contribution in rock-type discrimination over Landsat data. The results of the study show that AL-Hammad lineaments, recognized on images, were caused by major faulting zones that affected the crystalline basement.
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