Evacuation zones differ on Marlborough tsunami maps
A big earthquake hits, a tsunami warning comes and people ponder their next move.
Thankfully councils across the country have tsunami maps on their websites.
But, in Marlborough, the tsunami "high tide mark" differs depending on which map people use.
The council's main map is built mostly from raw and inexpensive topographical data, and GNS scientists say LiDAR (Light Detection and Ranging), taken from the air, should be used where possible.
The problem is, it's not available for all of Marlborough.
Marlborough emergency management officer Gary Spence said perhaps website users should be more clearly directed to the LiDAR map, by clicking on the 'layers' section on the main map.
"We only use LiDAR when we have it, and we have it for the lower Wairau Valley. Clicking on 'layers' on the council website will show the LiDAR layer," Spence said.
"It would be great if the Government stepped in and funded more accurate and innovative assessments, but you have to do it where there's LiDAR, and the cost is very high.
"I can't pinpoint exactly where a tsunami will stop, it could be anywhere. All maps are an indication of where scientists think the inundation line will run up to.
"And we don't want to lull people into a false sense of security. The message is, if you are near the coast in an earthquake, you need to move inland and to higher ground as soon as possible."
The Riverlands Industrial Estate, south of Blenheim, was in the LiDAR self-evacuation zone, but not the council's.
Big Chill Distribution was in the estate and depot manager Louise Fissenden said she would like to have the zones clearly marked.
"We don't have any special safety procedures for tsunami, but I'd prefer the council to have clear and accurate maps showing the zones on its website. You can't say it won't happen because it might," she said.
The nearby chemical coating company Equus also did not have a health and safety procedure for tsunami.
Managing director Brian Greenall said he was "more concerned about stuff blowing up than tsunami risk".
"Industrial accidents and moderate earthquakes are of more concern to us. The earthquake last year wrecked a lot of stuff around the industrial estate and we were a long time cleaning up, but there was no tsunami problem," he said.
"If we had a tsunami warning, our people would rock off home, pick up their kids and go because they all live in town and they would be able to get out before it got here. Even on the LiDAR map.
"I don't actually believe that map. The land on the other side of the highway is a lot lower, and there are two great ditches on the far side of the highway which is going to absorb a lot of stuff they say would hit the estate."
"Depending on how big it is, of course, I think we would be OK here. I think the effect would be about halfway between the two map versions."
- The Marlborough Express