COASTAL MULTI-HAZARD OCCURING SIMULTANEOUSLY OR CASCADINGLY: ASSESSMEMT METHODOLOGY

Abstract

Natural hazard assessment and zoning in Viet Nam mainly focuses on assessing single hazard without the consideration given to simultaneously or continuously occurring hazards . However, natural hazards are often closely related to each other and may occur simultaneously or cascading over time. This paper provides the assessment and zoning methodology for multi-hazard that occurs simultaneously or cascading based on probability theory. The methodology enables scholars to obtain a synthesis assessment of aggregated impacts due to simultaneously, cascading or cumulatively occurrence of natural disasters. Multi-hazard assessment and zoning process consists of 10 steps: (i) Definition of assessment goal and spatial domain; (ii) Identification of multi-hazard scenario; (iii) Development of a set of multi-hazard assessment indicators; (iv) Data collection and calculation of single hazard indicators; (v) Calculation of the impact index of a single hazard; (vi) Weighting the impacts of cross-hazard interaction; (vii) Calculation of multi-hazard impact index (without considering exceedance probability); (viii) Calculation of exceedance probability of a single hazard; (ix) Calculation of joint probability of
multi-hazard; (x) Multi-hazard assessment and zoning.