Spatial Design of Physical Network Robust Against Earthquakes

This paper analyzes the survivability of a physical network against earthquakes and proposes spatial network design rules to make a network robust against earthquakes. The disaster area model used is fairly generic and bounded. The proposed design rules for physical networks include: 1) a shorter zigzag route can reduce the probability that a network intersects a disaster area, 2) an additive performance metric, such as repair cost is independent of the network shape if the route length is fixed, and 3) additional routes within a ring network do not decrease the probability that all the routes between a given pair of nodes will intersect the disaster area, but a wider detour route does decrease it. Formulas for evaluating the probability of disconnecting two given nodes are also derived. An optimal server placement is shown as an application of the theoretical results. These analysis results are validated through empirical earthquake data.