September 2016 – NEW ZEALAND – A swarm of 100 aftershocks has continued to plague the North Island’s East Cape since a severe earthquake struck early on Friday morning. The quake – 7.1 in magnitude, 130km north-east of Te Araroa at a depth of 55km at 4.37am – was felt from Northland to Wellington in the North Island, and in the top of the South Island. Severe reports were felt in Gisborne and the Bay of Plenty.
The earthquake prompted a tsunami warning, which was rescinded after waves of 30 cm were measured off Gisborne’s coast. The ground continues to shake the East Cape region, and it’s likely to continue for some time, according to GNS. The Transport Agency says that is bringing with it a risk of rock-falls and slips on the roads, and it’s urging drivers to be wary.
The aftershocks were bringing increased risk at SH2 Waioeka Gorge, SH2 Maraenui, SH35 Motu Bluffs and SH35 Hawai to Te Kaha. The region to the northeast of New Zealand where the Australia plate meets the Pacific plate has a history of generating large magnitude quakes and tsunami. GeoNet received more than 5,000 felt reports in the 20 minutes after the 7.1 earthquake. GNS Science duty seismologist Caroline Holden said there was a flurry of aftershocks, including one M6.2 aftershock at 5.14 am and a 6.0 at 8.06 am. There have been more than 100 aftershocks since the initial 7.1 tremor.
GeoNet says the aftershocks can continue for some time, but there was no way to tell whether Thursday’s M5.7 shake was a ‘foreshock.’ Holden said seismologists were working to confirm all the signals, which were ‘messy,’ and map the shocks. “There’s been a flurry of aftershocks. We have a team and we’re monitoring the tsunami as well. We’re in constant communication with civil defense.” –Stuff