Considerations about the optimal period range to evaluate the weight coefficient of coupled resilience index

• Method to evaluate community resilience index of physical infrastructures.
• Analytical methodology to select the weight coefficients of each infrastructure.
• Interdependency indices which are evaluated using time series analysis.
• Application on the restoration curves of March 11th 2011 Tohoku Earthquake.

Resilience index can be used to plan mitigation actions of lifelines against various types of hazards as well as describing the reconstruction phase. In the paper, community resilience is defined as weighted sum of single infrastructure resilience indices. In particular, the paper addresses the problem of the optimal selection of the weight coefficients which are assigned to different lifelines for the evaluation of the resilience index in a region affected by natural disasters such as earthquakes. The proposed method is based on the analysis of the lifelines’ restoration curves using cross-correlation functions; however, when the data series is including coupled events, the coupling effect generates distortion in the evaluation of the cross correlation coefficient Si,j. This is the case for example when there are strong aftershocks during the lifeline restoration phase right after the main shock. The method is applied to the restoration curves recorded after March 11th 2011 Tohoku Earthquake. A criterion is proposed for the evaluation respectively of the interdependency index, weight coefficients and regional resilience index with long restoration curves data series.