Post-Earthquake Downtime Induced by Safety Cordons

Post-earthquake downtime has been increasingly recognized as a major contributor of economic losses. Safety cordons around the Central Business District (CBD) in Christchurch, New Zealand resulted in a ghost town after the February 2011 earthquake (see map). These wide-spread, long lasting access restrictions meant that even undamaged buildings were out of commission, due to concern that nearby damaged buildings may collapse onto them during an aftershock.

This research incorporates FEMA P-58 and REDi’s state-of-the-art damage and downtime estimates for individual buildings. Excessive residual drift in tall buildings triggers a cordon with a radius equal to the building height or the “fall radius.” Spatial analysis determines which buildings are located within each cordon. The cordon durations and other community-wide impeding factors can then be integrated into the downtime estimates for each building. Two key contributions of this research are the use of high-resolution, building-level analysis to model community-level recovery and the inclusion of the spatial relationships between each building, rather than considering them as isolated in space.