New Zealand’s perilous position on the Pacific Ring of Fire was drawn into sharp focus again today with the news that a 6.3 earthquake had struck near the small tourist village of Kaikoura in the South Island.
Kaikoura’s store manager, James Hills, described the chaos in his shop after the quake hit.
“Fair bit of panic – get out of the shop, everything was falling off the shelves. There’s been a little bit of damage, certainly not heaps, but yeah, there’s a lot of stuff fallen over.”
“Well, initially, we were up on the second floor and felt a slight movement, we thought, ‘that’s okay, that’s it,’ so we just took our seats, then it came on – to me, it was a rolling motion, quite firm, quite solid,” Kaikoura’s mayor, Winston Gray, told Radio New Zealand News, adding that there were some reports of minor damage throughout the city.” source
The Kaikoura earthquake seems to be part of a sequence that started yesterday. A magnitude 4.4 at 10:36am, followed by a 5.1 at 10:42am, that were centred just east of Seddon. Much like the Christchurch/Canterbury earthquakes which began in 2010, they are expected to continue for some time.
According to GeoNet, the quake hit 35 km north-west of Kaikoura at a depth of 52km.
The severe quake was felt all over New Zealand and had many people in the locality sheltering beneath desks and tables
The NZ Herald reported
Reader Paddy Brocherie wrote in to describe the quake as “the longest quake I’ve ever felt and I live in Christchurch“.
“Bad, bad, bad.”
Susan Allan said she felt the earth move in Riwaka – a “sharp rolling jolting for approx 30 seconds“.
The quake shook the house, but there was no damage, she said.
Further north in New Plymouth, Victoria Brooks felt the shake “very nicely”.
So far we’re hearing that the earthquake caused a landslide on State Highway 1 at between Kaikoura & Cheviot, the Coastal Pacific rail service has been halted at Kaikoura, and the TranzAlpine has stopped at Arthur’s Pass. Rail services between Picton to Christchurch have also been suspended.
At about 4pm NZ time Kaikoura Mayor Winston Gray said there’d been no damage to his office and he hadn’t had reports of damage anywhere else yet. Listen to his radio interview here.
Many phone users elsewhere in New Zealand reported that their services dropped out shortly after the quake, a reminder not to rely too heavily on telecommunications or the internet in New Zealand during a natural disaster. As with previous quakes in New Zealand news can be slow to make its way out, due in part to the remoteness and also because communication channels tend to fail.
Residents of Christchurch also felt the quake, many of whom are still waiting for their claims to be settled from the quakes that decimated their homes and businesses over 4 years ago.
A Kaikoura council report into earthquake prone buildings states
Kaikoura District is directly involved with seismic futures having numerous faults and thrusts within its boundaries. The formation of the seaward and inland ranges and valleys stand testament to this fact…
…Much of Kaikoura has a foreshore with a pea shingle subsurface that may attract liquefaction status. Liquefaction occurs where the subsurface soils react to seismic movement by behaving in a similar manner to liquid in terms of its ability to support a building with subsequent structural damage or catastrophic collapse as a possibility.
Liquefaction is normally a greater risk when shallow ground water is present and is in conjunction with the aforementioned pea shingle. Whilst there have been a number of reports relating to seismic activity in the district liquefaction has not been extensively investigated. The Institute of Geological and Nuclear Science in Wellington have no specific detail on this subject for Kaikoura. Similarly Environment Canterbury have little to offer on the subject within Kaikoura… more here
Environment Canterbury Civil Defence Emergency Management Group Plan (link) states
At Kaikoura a deep submarine canyon comes very close to the shore. Experts think it is possible for a local tsunami to be set off by a submarine landslide into the canyon. In the past they have modelled wave heights of up to 12 metres. These waves would come ashore within minutes.
“All people are vulnerable to a certain extent but some are more vulnerable than others. In Canterbury there are many communities
which could become geographically isolated during an emergency. Kaikoura, Mt Cook, Hanmer Springs and Hakataramea are examples of communities that might become isolated by earthquakes, landslips, avalanches and floods…”
Annex B of the report, giving the overall risk assessment for Kaikoura, is shown below (click to enlarge)
The reddit New Zealand community (below) was quick to start a discussion about today’s quake incident, our thoughts are with the residents and visitors in the affected areas.