A large 7.4 magnitude earthquake struck 690km north east of the Hauraki gulf at 12:49am this morning. According to GeoNet, there have been 16 aftershocks ranging from magnitude 4.5 to 5.5 in the 5 hours preseding the quake.
The initial seismic primary wave took 1 minute and 42 seconds to arrive at our seismic monitoring station on the North Shore and the quake was felt across the upper North Island and Bay of Plenty.
A small tsunami wave of 20cm was detected arriving at Great Barrier Island around 1 hour and 35 minutes after the 7.4 fault rupture.
The earthquake was along the Kermadec trench where the Pacific plate dives westward beneath the Australian plate forming the Kermadec megathrust subduction zone fault. This fault has a history of earthquakes with magnitudes exceeding magnitude 7.0.