Using Space Techniques and GIS to Identify Vulnerable Areas to Natural Hazards along the Jeddah-Rabigh Region, Saudi Arabia

Natural hazards have become the foremost geo-environmental issue in many regions worldwide, since rarely a year goes by without any catastrophic event that harms both urban structure and human life. These natural hazards are exacerbated by a number of physical and demographic factors and variables. The most common aspects of these hazards are floods and their related processes of soil and rock erosion of different types, landslides, volcanic activities, seismic movements of different magnitudes, as well as coastal erosion and sea floods on coastal zones. It is extremely dangerous to have all these natural catastrophic aspects within one region, which makes it susceptible to natural disturbances. A typical example is the area located along the Western coast of Saudi Arabia, between Jeddah and Rabigh. This area is currently witnessing an obvious development trend and dramatic urban growth, including a miscellany of urban and tourist settlements, in addition to mushrooming academic centers. However, the regions susceptibility to natural hazards was not considered during this development. The area comprises mountain chains of igneous rocks and complexes with extensive rock structures, including volcanic dykes and fault systems, which are susceptible to movement at any time. In addition, the area extends to the coastal plain to the west, which is almost covered by interbedded rocky and soil materials due to the transgression and regression processes that have taken place in the past. This makes the region vulnerable to sea flooding. The hydrological records, with a special emphasis on floods, along with the seismic frequency records show a recurrence of catastrophic events. These observations have been made in addition to physical observations in geologic and geomorphologic maps as well as satellite images, which point out the high vulnerability of the area to natural hazards at a time when the population growth is continuously developing. Based on these principles, the study aims to utilize space tools to extract physical data in a comprehensive approach as well as analyze and manipulate this data in the Geographic Information System (GIS), thus determining the areas vulnerable to natural hazards. More specifically, the study aims to produce thematic maps for each type of existing natural hazards, among which geographic zones can be classified with respect to different risk levels. It is a complete report that decision makers can utilize in order to apply tangible implements to mitigate the risk magnitude and thus identify areas with less risk. The authors hope that these areas can be considered in urban management and planning approaches.