An earthquake risk assessment framework for developing countries : Pakistan a case study

• Main Author: Khan, Shaukat ?Ali¯
• Published: University of Sheffield 2011
• Subjects: 363.3495091724
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556649

The devastation in the recent events of Kashmir (2005), Chengdu (200S) and Haiti (20 I 0) highlights the need for earthquake risk assessment (ERA) in developing countries. Kythreoti (2002) at the University of Sheffield, worked on the development of an ERA framework called EQ-RACY that was applied to Cyprus. It was concluded that a more comprehensive framework is needed to account for variable seismicity, tsunami, landslides, rockfalls, liquefaction, as well as for non-residential structures. It was also suggested to develop the ERA framework in a geographic information system (GIS) environment, and to develop more representative vulnerability assessments. This led to a project at the University of Sheffield to produce a comprehensive ERA framework for developing countries. The task is overwhelmingly huge for a single PhD project; therefore, the work is undertaken as a series of PhD projects. This thesis presents the development of the generic ERA framework for the project. The first aim of the work was the development of the probabilistic seismic hazard assessment (PSHA) methodology. The PSHA methodology by Kythreoti was enhanced to incorporate large magnitude earthquakes and historical seismicity to suit the diverse seismo-tectonics of other parts of the world. In many developing countries statistics on building stock are not readily available. Satellite imagery may be used as an alternative to field building surveys, but the current methods are not very reliable, need further enhancement, and are not very cost effective. A simple method is developed in this research for cost effective and rapid building stock assessments using medium resolution satellite imagery and minimal field sampling. The results of the new PSHA methodology are compared with previous studies. The risk results obtained for the district of Abbottabad in Pakistan after the Kashmir (2005) earthquake are 22% higher than damage estimated from observed data. Considering the fact that damage estimates from government data tend to underestimate damage, the results are considered reasonable. The spatial distribution of damage compared well with observed damage data. The ERA framework is applied to a study region between Islamabad and Peshawar within Pakistan and risk mitigation strategies are recommended. The study region is divided into 4 seismic zones and the assessed average annual insurance premiums were £3.9, £7.S, £12.7 and £ IS.9 per £ 1000. Under the present circumstances for preparedness, it is recommended that the government makes a contingency plan of approximately £600 million to cover residential loss, 31,000 deaths and 40,000 injuries. The study revealed that enforcement of seismic regulations can reduce monetary and life losses by 60% and 77% respectively, whereas seismic retrofitting can reduce monetary and life losses by 50% and 67% respectively. Appropriate response and recovery measures can reduce the loss of life by 39%.