Scenario-based earthquake risk assessment for central-southern Malawi: The case of the Bilila-Mtakataka Fault
Scenario-based earthquake risk assessment for central-southern Malawi: The case of the Bilila-Mtakataka Fault
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DOI：
10.1016/j.ijdrr.2021.102655
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发表时间：
2021-10-26
影响因子：
5
通讯作者：
Voyagaki, Elia
中科院分区：
文献类型：
--
作者：
Goda, Katsuichiro;Novelli, Viviana;Voyagaki, Elia
对马拉维中南部地区进行了区域地震风险分析，重点关注东非裂谷系统内的Bilila-Mtakataka断层，并结合当地人口暴露和建筑脆弱性信息。基于情景的地震风险评估考虑了Bilila-Mtakataka断层的几何形状、位置和破裂模式的不确定性以及地面运动的可变性，并基于最新的2018年全国人口普查数据。此外，根据建筑调查和对当地建筑材料的实验室测试制定了马拉维特有的地震脆弱性函数，以反映马拉维未加固砖石建筑的实际地震脆弱性。基于替代数据和模型的地震风险评估和敏感性分析的结果强调了与全球数据和模型相比，将有关地震灾害特征、人口数据和建筑物地震易损性的当地信息纳入其中的重要性。对于所考虑的案例研究区域，上述模型组件的个别影响往往会导致区域地震风险指标的20- 30%或更大差异，例如受影响的人口经历一定的地面震动强度水平或倒塌的住房单元数量。改进后的地震灾害风险评估在为未来的地震风险缓解政策和行动提供信息方面更为有效。
A regional seismic risk analysis for central-southern Malawi is conducted by focusing on the Bilila-Mtakataka Fault within the East African Rift System and by incorporating local information on population exposure and building vulnerability. The scenario-based earthquake risk assessments account for uncertainty in geometry, position, and rupture pattern of the Bilila-Mtakataka Fault as well as ground-motion variability and are based on the latest 2018 national census data. In addition, Malawi-specific seismic fragility functions, which were developed based on building surveys and laboratory tests of local construction materials, are implemented to reflect realistic seismic vulnerability of unreinforced masonry constructions in Malawi. The results from the earthquake risk assessments and sensitivity analyses based on alternative data and models highlight the importance of incorporating local information on seismic hazard characterisation, population data, and seismic vulnerability of buildings, in comparison with global data and models. For the considered case study region, individual effects of the above mentioned model components tend to result in 20-30 % or greater differences in regional seismic risk metrics, such as the affected population experiencing a certain ground shaking intensity level or the number of collapsed housing units. The improved seismic hazard-risk assessments are more effective in informing future seismic risk mitigation policies and actions.