Low detection capability of global earthquakes after the occurrence of large earthquakes: investigation of the Harvard CMT catalogue

We investigated the detection capability of global earthquakes immediately after the occurrence of a large earthquake. We stacked global earthquake sequences after occurrences of large earthquakes obtained from the Harvard centroid-moment tensor catalogue, and applied a statistical model that represents an observed magnitude–frequency distribution of earthquakes to the stacked sequence. The temporal variation in model parameters, which corresponds to the detection capability of earthquakes, was estimated using a Bayesian approach. We found that the detection capability of global earthquakes is lower than normal for several hours after the occurrence of large earthquakes; for instance, the duration of lowered detection capability of global earthquakes after the occurrence of an earthquake with a magnitude of seven or larger is estimated to be approximately 12 hr.