2026MNRAS.545f2043C

The origin of fast radio bursts (FRBs) has remained a mystery up to now. There are two kinds of process invoking neutron stars as an origin of FRBs, namely inner-driven starquakes and outer-driven collisions with interstellar objects (ISOs). The former origin should exhibit an earthquake-like statistical behaviour, while the latter should show a stochastic process. In this paper, we introduce a new statistical method by making use of the energy structure function of active repeating FRBs and earthquakes. We find that the energy structure function of FRBs exhibits a very different statistical behaviour compared to that of earthquakes. On small time-interval scales, the energy of an earthquake shows a tendency to decay with time interval, and the energy difference of a pair of events increases with time interval. Such a behaviour is not found in FRBs, whose energy function is very similar to that of a stochastic process. Our result shows that repeating FRBs may have an origin process differing from that of earthquakes, i.e. FRBs arise from a series of unrelated events such as collisions of a neutron star with ISOs.