Scheele FR. 2022. Methodologies for modelling fire following earthquake risk reduction and mitigation strategies in Wellington City. Lower Hutt (NZ): GNS Science. 24 p. (GNS Science report; 2022/53). doi:10.21420/TZ7S-3G53.
Abstract
Fire following earthquake (FFE) is a rare but potentially catastrophic phenomenon in urban areas where the capacity of emergency services to respond is overwhelmed. Wellington City has many characteristics contributing to the risk of FFE, including high seismic hazard, closely spaced timber-clad buildings, vulnerable gas and water networks, a windy climate, steep topography and the potential for road access to be obstructed. To support decision-making, this study reviews methodologies for evaluating risk reduction and mitigation strategies. The FFE process is discussed, identifying risk factors and reduction or mitigation strategies at each stage. The process includes pre-earthquake fire risk, the earthquake event, ignition, fire spread, fire cessation and post-earthquake fire risk. Risk factors include building and infrastructure vulnerability, demographics, climate, geography, ignition sources, fuel, water availability and human behaviour. Risk reduction involves resilient buildings and infrastructure, firebreaks and community awareness and preparation. Mitigations include automatic fire suppression, shut-off valves and firefighting by emergency services and residents. Existing models that may be used for evaluation of risk reduction and mitigation strategies are reviewed. The majority of models address the ignition, fire spread and suppression stages of FFE. Through the discussion, the suitability of model application to Wellington City is discussed, including the potential for newly developed models. This study concludes with a series of recommendations for further model development. The recommendations are (1) investigate ignition risk factors for the local context, (2) further develop data for Wellington City for use in modelling, (3) develop an improved FFE risk matrix, (4) develop network analysis models and (5) develop an agent-based model for a holistic evaluation of risk reduction and mitigation strategies across all stages of FFE. (The author)
