A major undersea earthquake struck off East Cape early this morning.
Friday, 2nd September 2016
A magnitude 7.1 earthquake struck 125 km north-east of Te Araroa at 4:38 this morning. GeoNet reports that the earthquake was 22 km deep. The U.S. Geological Survey also reports the quake as magnitude 7.1, centred 166 km north-east of Gisborne at a depth of 19 km.
The quake generated a tsunami that was recorded on gauges at East Cape and Great Barrier Island. The first wave was detected at about 4:55 a.m., about 20 minutes after the quake. The largest sea level change was 30 cm. It is not yet clear whether the tsunami was generated by displacement of the sea floor or the triggering of an undersea landslide by the earthquake.
A magnitude 5.7 foreshock struck the area yesterday morning.
Significant aftershocks have followed this morning’s earthquake. The U.S. Geological Survey reports seven aftershocks of 5th magnitude to 8 o’clock this morning. GeoNet reports that a magnitude 6.2 aftershock struck at 5:14 a.m. and a magnitude 6.0 event occurred at 8:06 a.m.
The Ministry of Civil Defence and Emergency Management issued a marine and beach tsunami threat statement for eastern coasts of the North Island from Northland to Mahia Peninsula. It is expected that unusually strong currents and water flows will occur near the shore for several hours.