Top of South Island rocked by flurry of early morning earthquakesGEONET A magnitude 4.6 quake struck near St Arnaud early on Thursday. A strong earthquake shook up the top of the South Island early on Thursday, followed by a string of aftershocks. GeoNet said the 4.6 magnitude quake struck at 4.13am, centred 30km northeast of St Arnaud at a depth of 7km. Felt reports were received from 323 people by 5.30am. That quake was followed by a magnitude 4.0 quake in the same area at 4.51am at a depth of 21km, then a magnitude 3.0 at 10km depth, a magnitude 3.3 shake at a depth of 10km at 5.11am, and a magnitude 3.6 aftershock at 5.34am at a depth of 13km.

Source: Stuff April 19, 2017 18:01 UTC