Home Uncategorized RMS Commentary on the New Zealand Earthquake

RMS Commentary on the New Zealand Earthquake

0 1

Highlights :

– Though a smaller magnitude than the M7.1 Darfield earthquake on September 3, 2010, Christchurch city was significantly closer to the epicentre, and damage is reported to be significantly higher.

– Christchurch city center experienced shaking of MMI intensity VIII (‘severe’ shaking), which is greater than the V reported in the city during the Darfield Earthquake.

– Fatalities from the earthquake currently stand at 65; however, this number may rise as hundreds of people are still trapped.  The relatively high death toll compared to the September earthquake is driven by the daytime event when the central business district was at its busiest and the higher intensity of shaking experienced in the city.

– Initial reports indicate the level of damage is severe in Lyttelton and many buildings in Christchurch have sustained significant structural damage.

On Tuesday, February 22, at approximately 12:51 pm local time, a shallow, powerful magnitude 6.3 (moment magnitude) earthquake occurred near the port town of Lyttelton, on the South Island of New Zealand, approximately six miles south-east of Christchurch.

The USGS ShakeMap shows the area close to the epicenter to have experienced ‘severe’ shaking of intensity VIII on the Modified Mercalli Intensity (MMI) scale, where the potential for damage is moderate/heavy for resistant structures and heavy for vulnerable structures. According to the USGS PAGER system, Christchurch (population ~ 364,000) experienced such shaking.

This is greater than the intensity V shaking Christchurch experienced from the Darfield earthquake (7.0 Mw) on September 3, 2010. The epicenter of the Darfield earthquake was approximately 27 miles west-northwest of Monday’s 6.3 Mw epicenter and around 27 miles west of Christchurch.

According to the USGS, the February 21 earthquake occurred as part of the aftershock sequence of the Darfield earthquake (although there is no specific structure linking this event to that of September). Since the September 3 event there have been approximately six aftershocks of Mw5.0 or above in the Christchurch region with the February, 21 earthquake representing the largest aftershock to date. The USGS has reported that the February 21 earthquake was the result of oblique-thrust faulting, and is broadly associated with the regional deformation at the boundary between the Pacific and Australia plates.

A state of emergency was declared in the Canterbury region and will last at least five days. Prime Minister John Key reported the death toll from the earthquake to be 65, though this figure could rise as hundreds are still trapped in damaged buildings. Christchurch Mayor Bob Parker estimates the number trapped to be greater than 100. Two buses were crushed by collapsed buildings, contributing to the high death toll from the event.
There are reports of landslides at Sumner and concern for similar incidents throughout the Banks Peninsula area. Western suburbs, such as Hornsby, appear to have escaped much of the devastation that has affected the central and southern parts of the city.
In New Zealand, all residential property owners who buy fire insurance automatically acquire EQCover, the EQ Commission’s insurance cover.  Under the EQC policies, dwellings (buildings) are insured up to a maximum of NZ$100,000 (plus tax), personal effects (contents) up to NZ$20,000 (plus tax), and land cover is provided in addition to these limits.

The role of the private market on the direct insurance side is firstly to extend the coverage to residential above the EQC limits for both buildings and contents, and secondly provide coverage to commercial and industrial properties. It is expected that where dwellings have been severely damaged by the ground shaking, the repair and reconstruction costs will exceed the EQC “first loss” limits of NZ$100,00 for buildings and NZ$20,000 for contents. Almost all industrial and commercial policies are written on an all risks basis and most policies include full value earthquake cover. Private insurers therefore are expected to be play a role in the repair of the predominantly commercial properties affected by the earthquake.

While no statement has been made yet by the NZ Earthquake Commission, all major aftershocks since the Canterbury Earthquake of September 4, 2010 have been classified as separate events by the Earthquake Commission, with separate claims procedures and deadlines.

Source : RMS Press Release