New Zealand earthquake leads to tsunami alert

Those, with friends or family in New Zealand, living in Switzerland, may be unaware of the recent earthquakes that hit New Zealand, or may have been confused by some reports.

According to GeoNet, New Zealand’s official source of geological hazard information, six severe¹ earthquakes have been recorded since midnight New Zealand time. The most severe measuring 7.5, occurred at on Monday, 14 November 2016 at 12:02:56 am, at a depth of 15 km, 15 km north east of Culverden. GeoNet gave the following coordinates: -42.69 173.02. Here is it’s location on a map. This earthquake, described as the Cheviot or Hamner Springs earthquake, led the New Zealand’s Ministry of Civil Defence & Emergency Management to issue a Tsunami warning.

The image below shows predicted wave heights around the shores of New Zealand and the Chatham Islands. Predicted wave heights range from 0.2 to 5 metres.

Since the first severe shake, five more quakes were registered. One of 5.6, 5 km west of Culverden at 12.16am, one of 6.2, 15 km north of Kaikoura at 12:32am, another of 6.2, 25 km north of Kaikoura at 12:52am, one of 6.0, 15 km north of Kaikoura at 2:31am, and one at 6:18am of 5.1, 5km from Kaikoura. A full list of earthquakes is shown here. New Zealand’s GeoNet uses the New Zealand Modified Mercalli Intensity Scale rather than the Richter Scale to measure earthquake intensity, which measures quakes from weak to severe, with severe ranging from damaging to completely devastating.

The US Geological Survey recorded the first quake at 7.8 Mww².

According to a report on Radio New Zealand’s website, scientists say the quake could have been caused by a numbers of faults.

According to a report on the same website, posted at around 4am NZ time (4pm Swiss time) the emergency service provider, St John, said it is now starting to get reports of injuries from the earthquake area, including Culverden area and Kaikoura, but provided no specifics. Police said they were still trying to verify reports a building had collapsed in Kaikoura.

According to the same report, the Hutt City Council said tidal indicators showed the largest waves had passed in the Wellington harbour, however in Canterbury, the civil defence and emergency management group, said it was evacuating people along its entire coast area while Canterbury group controller Neville Reilly said it was evacuating people in coastal areas from Kaikoura to Waimate. Residents of Cloudy Bay in Marlborough, famous for its wine, were reportedly being evacuated.

In a video posted on the Radio New Zealand website early in the morning, New Zealand’s Prime Minister John Key told a media conference : “On the best information we have, there have been two fatalities”, adding later that the tsunami warnings had been downgraded to coastal warnings, but that the Kaikoura area had been “cut off from a road perspective.”

One Christchurch resident interviewed by Le News, said there had been no damage in their house, but that the first shock was unusually long, and went on for what felt like minutes.

¹Â MM7 Severe earthquakes are described as damaging, resulting in general alarm. People experience difficulty standing. Furniture and appliances are shifted. Substantial damage to fragile or unsecured objects. A few weak buildings are damaged.
² Mww – Moment magnitude derived from a centroid moment tensor inversion of the W-phase.

More on this:
First earthquake (7.5) details from GeoNet
First earthquake details from US Geological Survey

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