The European Mediterranean Seismological Centre (EMSC) based near Paris which runs a popular earthquake-reporting mobile app said that user-generated reports reached an all-time high after a 4.15 pm aftershock near Petrinja, Vecernji List daily reported on Thursday. In only a few minutes some 22,000 people had notified the EMSC via the app, although the tremor itself was only a weaker aftershock some four hours after the massive 6.2 magnitude quake had struck the area shortly after noon.

The number of reports of the main earthquake certainly would have been higher, but the lines could not withstand so much traffic, said Remy Bossu, seismologist and leader of a nine-member team which runs the app that many Croatians had downloaded in the wake of the 22 March earthquake in Zagreb.

Their Last Quake app lets users report any tremors or shaking immediately, and enables them to find out in less than 15 seconds whether their senses have deceived them or if it was indeed an earthquake, calculating in real time the estimates of quake magnitude and location even before seismologists can even read or publish the data.