Determining appropriate and accessible roads after earthquake by using GIS for the city of Kashan

Introduction: Urban transportation network especially in big towns has basic role in earthquake crisis management and on another side, this network is known as the most vulnerable against earthquake. Besides losses of lives, losses related to lifelines such as electric networks, water and sewage system network, transportation infrastructures are also remarkable. So some act to identity and determine the accessible and optimal road after an earthquake for urban transportation activities such as relieving car, ambulances and fire fighting cars, is essential. However, complete and systematic research about this topic has not done. Method: This study is aimed to evaluate the roads and their vulnerability in the event of an earthquake, with ۶/۵ magnitude in Kashan. At first, a model is introduced to assess damage and vulnerability of road via calculation of the blockage level with considering factors such as building debris density, building characteristics and the relative distance between buildings and roads. Then via extending this model on ۵۷ main roads and ۴۱ homogenous units in the Kashan and information about Kashan urban transportation network in GIS, degree of lateral and longitudinal blockage is estimated and useable maps is visualized. Findings: According to the findings, it should be said that a) the width of the path is one of the factors affecting its obstruction after the earthquake. The wider the path, the greater the cross-sectional obstruction. b) Longitudinal obstruction is more in the old tissue. This is due to the materials used in construction and the instability of the buildings. Conclusion: Due to the characteristics and natural conditions of urban spaces and the density of investment and environmental loads, most large cities, including Kashan, are facing natural disasters, especially earthquakes. Therefore, it is necessary to pay attention to the necessary planning regarding the immunity of cities and their less damage, and any recommendations must be implemented in a suitable organizational context.

کلیدواژه ها:

Earthquake ، road blockage ، GIS ، زلزله ، انسداد مسیر ، سیستم اطلاعات جغرافیایی.