Probabilistic two-hazard risk assessment of near-fault and far-fault earthquakes in a structure subjected to earthquake-induced gas explosion

Over the past decades, several studies have compared damage induced by near-fault and far-fault earthquakes in a deterministic approach. Following a probabilistic approach and generating several scenarios, the present study was aimed at assessing the probabilistic two-hazard risk of a structure concurrently subjected to earthquake and earthquake-induced blast. The two critical events (earthquake and blast explosion) were considered as compatible and dependent events, such that the blast would occur simultaneously with the earthquake and as the result of it. The probabilistic two-hazard risk was evaluated in two separate phases: one was characterized by near-fault earthquakes with blast; and the other phase was defined by far-fault earthquakes with blast. Comparing the probabilistic risk for the two phases revealed that the probabilistic risk of the near-field earthquake, though with a long return period, is substantially greater than that of the far-fault earthquake.