Dear Institute of Geological and Nuclear Sciences Limited

I am making an OIA request with the purpose of clarifying statements made on the QuakeCore website where they cite the work of GNS regarding the updated National Seismic Hazard Model. https://nshm.gns.cri.nz/

https://quakecore.nz/research-project-st...

“Aotearoa New Zealand’s best estimate for how much and how often the ground will shake in future earthquakes comes from Te Tauira Matapae Pūmate Rū i Aotearoa, the National Seismic Hazard Model (NSHM).

A new version of the model was released in October 2022 showing, on average, a 50% increase in hazard over the previous model published a decade earlier. While we may not feel like celebrating the higher hazard, we can celebrate that we now have an up-to-date, state-of-the-art understanding of earthquake hazard across the country.

The result is a nationwide increase in seismic hazard we can’t ignore. Regional breakdowns show most regions have either the same or an increased level of hazard, and some regions have twice to three times their previous level. The increase arises mainly from new ways of estimating how the ground surface will behave during earthquakes. Ground conditions have a big impact on level of shaking and can vary greatly within a city. Improved modelling of the Hikurangi subduction zone and complex earthquake sources have also contributed to the increase.”

I can not find on either website clarification of which regions have an increased level of risk or a two to three times seismic risk.

1/ Will these regions with increased hazard be identified?

I believe it is important that these regions be identified as the statement is signalling a significantly heightened level of risk to life and property and that the data already exists which would help to rationally assess potential outcomes.

Let me provide an example of an assessment which had I known of prior would have influenced a decision to purchase a property in Fitzherbert Avenue Palmerston North.

This is from my website

“The very comprehensive Report of the Manawatu-Wanganui Regional Lifelines Project in January 2005 warning that Palmerston North will be affected by an earthquake of magnitude 8 at least once every 150 years has been discovered on an archive.
The frequency of a magnitude 8 on the Wellington Fault affecting Palmerston North is more than twice that of the Alpine Fault which produces an 8 approximately every 300 years.
This has this been hidden from the public. Note the Hikurangi trench off the East Coast can produce a 9. The probability is estimated at 25% over the next 50 years.”
https://turiteadocuments.wordpress.com/w...

PNCC has subsequently deleted this report from its website and the internet archive.

Page 94

“Fitzherbert Avenue bridge, Rangitikei Line railway line overbridge, Milson Line railway line overbridge and the Gillespies Line railway overbridge are ones identified as "at risk" assets. Collapse of these bridges during an earthquake event would have impacts in terms of emergency service access, consequential damage to services attached and a high economic cost to the community for asset replacement. The improvement programme includes a seismic screening task to review the risk of structures and service •

Palmerston North City Council bridges are designed for the high flood flow scenario. Large waterway areas and high vertical clearances are therefore very rarely surcharged. Problems such as silt/debris deposition resulting in waterway blockages and scouring that can cause undermining associated with high flood flows present the highest risk to a bridge.”

Page 143

“Fitzherbert Avenue - Palmerston North City Council - Ferguson Street to Fitzherbert Bridge - vulnerability to the seismic hazard. In particular, it is thought that severe liquefaction damage could occur to this critical road, isolating the Fitzherbert Bridge and possibly damaging the several critical civil, energy and communications assets contained within Fitzherbert Avenue.”

When renovating our Fitzherbert Avenue property we discovered our building was sitting on fine powdery silt. We called in Ormond Stock Associates to assess the strength of the foundations and this resulted in considerable extra expenditure to hopefully secure the structure. PNCC advice was also sought and a team did a site visit and made recommendations. The Lifelines Project needs a major revision or replacement.

The National Seismic Hazard Model has thumbnail summaries for identified fault zones. These are helpful but need further information as to frequency, images from google earth, precise location, their own webpage etc.

2/ Will full details be made available to the public? A disturbing example under Palmerston North with an earthquake range from 7.56 to 9.6

https://turiteadocuments.wordpress.com/w...

A very concerning document has survived a purge by PNCC from its website and the internet archive. This draft states up to 127 will be killed in an earthquake-induced collapse of one or both the Turitea dams. Dora Luo, Water Assets Engineer, faced opposition from PNCC and she subsequently left.

"The Council communication officer believed we should inform the affected residents straight away. But the question is what we can tell them before we are confident with the likelihood of failure."

https://turiteadocuments.wordpress.com/w...

An Excel-style document which identified possible deaths at various times of day also appeared on PNCC’s website only to be later deleted. When I found this document I was shocked at what I saw. It was subsequently lost when my computer was attacked.

Dora Luo revealed at an engineers seminar that PNCC could not decide what to tell property owners downstream should the Turitea dams fail. What, if anything, have they been told??

“Potential inundation mapping has resulted in challenging discussions within Council regarding whether and how we should communicate with the affected property owners and how it is going to affect the Council’s duty of care under the Law”

See page 11 506 A

https://web.archive.org/web/202206071305...

3/ Has GNS Science had any involvement with either the Lifelines Project or the Turitea Dams?

4/ Were there any communications on seismic issues with Dora Luo?

5/ Has GNS Science ever been consulted by anyone at PNCC, especially in light of question number 2?

Additional information is available on Dora Luo and her role including screenshots of seismic data from GNS Science and the concerns held for the earthquake-vulnerable water storage facilities.

https://turiteadocuments.wordpress.com/t...

Thank you
Yours faithfully
Paul Stichbury