The figure shows observations on NORSAR’s seismic stations at the Troll base in Antarctica and in Hedmark, southern Norway.

One of the Strongest Earthquakes in New Zealand in 200 years

NORSAR reports that New Zealand’s South Island was struck by one of the strongest earthquakes the country has observed in the past 200 years November 13, 2016.

According to both the U.S. Geological Survey and New Zealand’s Seismological Observatory GNS Science, the earthquake had a magnitude of 7.8 which makes it to one of the five strongest recorded earthquakes in New Zealand.

 

Recorded at Norwegian seismic stations

 

Shortly after the earthquake happened, NORSAR’s seismic stations in Norway and at the Troll base in Antarctica recorded strong signals of the event (see Figure). The main shock was followed by a significant number of aftershocks with magnitudes up to 6 on the Richter scale.

 

Heavily stricken region

 

The earthquake’s hypocenter (rupture starting point) was located approximately 95 km north of Christchurch, which, with a population of 375,000 is the largest city on New Zealand’s South Island. This region was heavily stricken by several earthquakes in the period 2010-2012. The focal depth for this new earthquake was provided at 15 km (GNS) to 23 km (USGS).

- This is probably one of the reasons why the extent of damages and losses are comparably low. Other, probably more pivotal reasons for the low numbers of casualties were the affected region’s low population number, as well as the low vulnerability of the prevalent building stock, says Dominik Lang, Head of Department Earthquake Hazard and Risk.

According to GNS Science, the earthquake’s epicenter was located 15 km north-east of the small city of Culverden in Hurunui District, a 8660 sq.km. large area with only 12,700 inhabitants. The existing building stock mostly consists of one-story timber frame buildings with light-weight roof systems.

 

Explains the tsunami warning

 

Even though the epicenter was located onshore with a significant distance to the eastern shore of the island, a tsunami warning for all of New Zealand’s coasts was initially released and kept active for several hours after the quake. According to New Zealand scientists, the tsunami warning was released since the earthquake’s fault plane projected offshore and the predominantly strike-slip source mechanism involved thrust motion. - This may lead to an uplift or drop of the sea floor and thereby generating tsunami waves, says Lang.

 

Complex pattern of quakes

 

Like other large earthquakes in New Zealand, this quake appears to have involved jumping from one fault rupture to another in a complex pattern. This compound style of rupture was a feature of the magnitude 7.1 Darfield quake of 2010 where up to eight neighboring faults ruptured almost simultaneously.

Associated companies:


Related news

Latest news

New contract: Windcat 41 - no 17 in the Servogear series

Servogear announces the signing of a new contract with Windcat Workboats BV for the delivery of Servogear Controllable Pitch Propellers (CPP)  for their new vessel Windcat 41. 

Seacat Enterprise to be launched January 12th

Seacat Services, is preparing to launch its first High Speed Utility Vessel (HSUV), Seacat Enterprise at January 12th.

Norsafe Signs Contract with the Swedish Coast Guard (KBV)

On Wednesday 21st December, Norsafe signed yet another new contract with the Swedish Coast Guard (KBV) to deliver nine new Magnum 750 MKII boats.

A Unique Second-generation Tomograph is Developed

A new gamma-ray tomograph designed to image up to 4” diameter pipes, is developed by CMR Prototech for the Saskatchewan Research Council (SRC) in Canada.

Sohome launches a new website

Sohome has launched a new website that makes it easier to find key information. 

Sohome AS receives orders for Johan Sverdrup Project

Sohome AS is proud to be a sub-contractor to Intelecom AS for the Johan Sverdrup Project. 

New 55'' Ultra High Definition Chart and Planning table passes Type Approval testing

Most advanced maritime display system ever produced, the 55'' Ultra High Definition Chart & Planning table, enables Integrated Bridge System manufacturers to develop new multi-data solutions.

Norsafe's experience in the Polar Code Pays Off

In readiness for the introduction of the Polar code, Norsafe has become the first LSA supplier to have executed full scale tests and trials 

Øglænd System Group winner of Business of the Year Award

Øglænd System Group won the Business of the Year Award in the Stavanger-region 2016.