Fault avoidance zone needed in Franz Josef - report

7:18 pm on 4 February 2020

A new study has reinforced the risk that a massive loss of life will occur in the Franz Josef township during a big quake.

Alpine Fault drilling

The study aims to inform locals and tourists of the significant risk to the area should the Alpine faultline go off. Photo: RNZ / Veronika Meduna

The Otago University study said a 200m wide 'fault avoidance zone' should be created to prevent further development in the area.

Study supervisor, Professor Virginia Toy, said buildings straddling the fault will be affected by 8m horizontal and 1.5m vertical ground displacements, which could result in people dying.

She said this hazard, along with rock avalanches and debris flow was well-known, and needed to be accepted by public lawmakers.

Based on on 2016 numbers, Franz Josef/Waiau had around 510 residents but has at least 600,000 tourists visit a year.

The study conducted by PhD candidate Bernhard Schuck, aimed to inform locals and tourists of the significant risk to the area should the Alpine faultline go off.

"The latest research is a timely reminder that following the recent White Island eruption, and a significant flow of debris that wiped out monitoring equipment at the famous Alpine Fault outcrop at Gaunt Creek, just north of Franz Josef, this December just gone, being prepared for natural hazards in New Zealand's dynamic landscape is crucial," Professor Toy said.

Schuck said that this study would also work to reinforce that none of the past mentions of a Fault Avoidance zone were exaggerated.

The Westland District Council had considered implementing the zone in their district plan in 2016, but scrapped it due to the threat of legal action.

This was despite prominent earthquake scientists writing a letter against the move.

In a late January report, planning and customer services manager, Fiona Scadden, outlined the Council's options for managing land issues in Franz Josef.

"While risk of these natural events and associated natural hazards has been known for a long time, arguably the focus on managing that risk has increased in the last 15 years," the report noted.

The report stated that there were no current previsions to deal with the eventual relocation of key infrastructure within flood or fault rupture areas.

Currently, three options have been put forward to the council.

This included doing nothing, reinstating Proposed Plan Change 7, which would mean the fault avoidance zone being implemented, or developing a strategy to manage land issues.

The report has recommended option three, which would develop a strategy.

Option two was not recommended. "Reinstating the proposed plan change does not provide an opportunity to engage with the Franz Josef/Waiau community with an 'open mind'," The report concluded.

The Franz Josef strategy is expected to be approved by the Council in November this year.

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