On 22 March , an intense earthquake ( 5.4 on the Richter scale ) hit the city of Zagreb , at 6:24 AM ( CET ) and was followed by multiple smaller earthquakes ( the second with a magnitude of 5.0 and third a 3.7 on the Richter scale ) .
The second aftershock of the 22 March earthquake in Croatia had a magnitude of 5.0 on the Richter scale , and the third had a magnitude of 3.7 .