Henderson Bay in Aupouri holds tsunami record

Henderson Bay, the scene of New Zealand's biggest tsunami. Photo / File

Henderson Bay, on the Aupouri Peninsula, holds a record that no other coastal community will be anxious to beat.

According to Niwa scientist Darren King there is strong evidence that New Zealand's biggest tsunami occurred there between 1450 and 1480AD, leaving deposits more than 30 metres above sea level and reaching about a kilometre inland.

Mr King made that observation alongside the news that scientific records of palaeotsunamis in New Zealand could now be accessed in a new "one-stop information shop.

Palaeotsunamis are those that occurred before written records existed, and have been discovered by investigating geological and anthropological evidence.

That information, previously stored in old spreadsheets or historic documents, has been transferred to an interactive map and database that enables users to search records by location, time and strength of scientific validity.

The map reveals that palaeotsunamis have occurred along almost all parts of the New Zealand coastline, but with greater concentrations on both coasts of the upper half of the North Island.

Mr King said the database was designed to increase awareness of the tsunami hazard, and aid the analysis of palaeotsunami information.

"If you are assessing tsunami risk, it is helpful to know the history of past events in your area. This is an easy way to look at multiple records to understand risk profiles based on the available evidence," he said.

"We think this database has a broad audience, including environmental managers, civil defence staff, researchers and the wider public, who now have an easy way to look at multiple records, explore the data and look at what has happened in the past.

Along with locations, each record could include information on how far the tsunami travelled inland, where the information came from, maximum water heights, what damage was caused, the strength of the evidence and the date range of when it occurred. Records dated back to pre-historic times.

The New Zealand Palaeotsunami Database can be found at http://ptdb.niwa.co.nz