Tom’s been shaken out of bed again, it seems. A 6.0 aftershock hit Tonga.
You know, I’ve known him for a while now, and I think it’s safe to say that he’s going to be extremely grumpy about this.
The U.S. Geological Survey said at least six aftershocks occurred near Tonga, while others were recorded near Fiji and Vanuatu. The strongest aftershock occurred at 12:25 a.m. local time at a depth of almost 24 miles.
And here’s why the quake didn’t cause a dangerous tsunami:
Unlike the quake that triggered the 2004 Boxing Day tsunami, the 7.8-magnitude jolt off Tonga caused little more than a 20 to 40-centimetre wave surge.
The quake struck on the northern boundary of the Pacific and Australian plates, northeast of Tonga, at 3.27am yesterday (NZ time).
It was the same magnitude as the 1931 Napier quake – but GNS Science seismologist Warwick Smith said because it was centred 60 kilometres beneath the sea floor it produced only a small surge.
The Boxing Day tsunami was caused by a 12,000km underwater shelf being lifted 10 metres by a magnitude 9 earthquake off Indonesia.
Waves generated by yesterday’s quake took about three hours to reach New Zealand – and when they arrived were “a few centimetres” high.
Dr Smith said if the quake – felt as far away as Wellington and Wanganui – had generated a larger wave, it would have affected the North Island’s entire northeastern coastline, including Auckland.