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Research Papers

Issue date: 
Category: 
NZ earthquakes
Paper number: 
41

Analysis of Te Anau residents' impacts, awareness & preparedness following the 2003 Fiordland earthquake

G. S.Leonard, D. M. Johnston & D.Paton

ABSTRACT

On August 22, 2003, a magnitude 7.1 earthquake struck the Fiordland area of the South Island of New Zealand. The largest urban area affected was Te Anau, a town of 678 households, located approximately 75 km from the epicentre.

In April 2004 a postal survey of residents of Te Anau was conducted primarily to estimate (a) damage and losses (insured and uninsured), (b) awareness of the earthquake hazard, and (c) preparedness for earthquakes. Of 600 questionnaires mailed out, 486 were successfully delivered and of these a return rate of 33% was obtained (response n=162). Ninety-two percent of the respondents to this survey stated that they had experienced the earthquake. The remainder were most likely out of town.

Sixty-four percent of respondents experienced damage or loss from the earthquake, but the types of damage were relatively minor in most cases (the majority of respondents had small appliances undisturbed). Of those who experienced damage, 13.3% did report entire structure distortion. There is a significant correlation of lower damage to indicators of higher preparation prior to the event. Conversely, respondents who suffered damage have a slightly higher intention to prepare in the future in terms of preventing damage and definitely seeking information on risk, but not in terms of involvement in a local discussion group.

In terms of preparedness, those who own their homes appear to be more than twice as likely to secure moveable objects. Many of the earthquake preparedness actions suggested by the questionnaire have been completed by only a minority of respondents, either before or after the earthquake, and regardless of whether or not they experienced damage. Preparedness actions {especially restraining household objects) that were conducted specifically to protect against earthquakes appear to have been more effective at reducing damage/loss from this earthquake than if those same actions were done for other reasons. Difficulty and cost of preparedness actions · are not major reported barriers to preparedness actions. Instead time, perceived effectiveness and perceived probability of an earthquake are the major reported barriers.

The total sampled insured loss was $0.20M and can be projected to between $0.98M and $1.40M of insured loss for the whole community. Total reported uninsured loss was only $0.01M which is projected to $0.03M for the whole Te Anau community. Completion of preventive measures by respondents is correlated to their mean loss; the mean value of loss was more than five times greater for households who have not 'secured moveable objects in [their] home' at any stage. More of those with damage/loss reported taking time, and a longer period, to get their home back to normal. This is a significant disruption, and possibly hardship/frustration not sampled by the direct losses. Actual time taken cleaning up, in hours, was on average quite low.

Two-thirds of houses were reportedly constructed after 1970. There was less exterior hairline cracking in wood-clad houses, but entire structure distortion was slightly more common in wood and stucco-clad houses. A third of respondents do not know what type of ground is under their site, and of those that do, damage was significantly less on river gravels than on other reported substrates. Most houses in Te Anau are on flat to gently sloping land, with no significant difference in damage between the two.

People who experienced damage/loss from the earthquake have, on average, lived in their house for a significantly shorter length of time. Eighty-five percent of respondents report having home insurance and 87% report having contents insurance, however a slight bias towards higher socio-economic respondents may mean that this is higher than the actual insurance level for Te Anau. The majority of insurance rates have not gone up and almost no one has had difficulty getting insurance cover since the event. Those with damage now consider themselves more knowledgeable about how to reduce or prevent damage from earthquakes than those without damage.

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