By JO-MARIE BROWN
Scientists investigating whether a tsunami could hit the Bay of Plenty believe six large tidal waves have swamped the area in the past 5000 years.
Soil samples have been analysed at the start of a 3-year study on tsunamis commissioned by the Bay of Plenty and Waikato regional
councils.
The results show at least six large tsunami have occurred since 2800BC - caused mainly by volcanic eruptions and earthquakes - but the size of each wave is not known.
Environment Bay of Plenty's regional civil defence officer, Russ Martin, said there was no way of predicting when a tsunami might hit next but people should remember that the region's coastline was vulnerable.
"This is a rare event but it's not impossible. These events have happened before on a number of occasions," Mr Martin said.
"We can't ignore the very low probability events because they are the high impact ones."
The increasing number of houses being built along the Bay of Plenty coastline was of concern because more people and assets would be affected should there be another tsunami, Mr Martin said.
"Week by week, month by month, year by year ... that risk equation is growing all the time."
The next two stages of the study will examine what source would most likely generate a future tsunami, what damage it could do and what could be done to minimise the risk.
The findings could influence future urban developments along the coastline and decisions on localities of major new amenities.
Mr Martin said that New Zealanders underestimated the amount of damage a tsunami could do because the biggest to date happened before human settlement.
Tracing tsunamis
* Soil samples have been taken from the Coromandel peninsula through to Cape Runaway since October.
* Tsunamis detected by soil marks and deposits of shells and other items from the sea floor.
* Tsunamis are believed to have hit the Bay of Plenty in around 2800BC, 1200BC, AD150, 203-1200, 1250, 1400-1500.
