Sea cliff instability hazard assessment for coastal management in Chabahar, Iran

Abstract

Hazards from sea cliff instabilities are increasing because of the growing human occupation in coastal areas. Assessment of cliff hazards is very important in order to develop appropriate coastal management plans. In this study, a semi-quantitative heuristic method was developed to assess instability hazard for rocky coasts at Chabahar (Iran) along the northern coastline of the Gulf of Oman. In this method, seven factors affecting cliff instability, including: wave exposure, cliff height, cliff slope, rock resistance, lithology, bathymetry and beach width, were used to calculate an instability hazard index, from which a hazard map was constructed for the study area. Results were validated by statistical analysis of the previous instabilities detected by comparing old and new satellite images. According to the instability hazard class and cliff height, a hazard zone from the top of cliffs was determined within which development is not recommended.