Tsunami threaten New Zealand

Tsunami threaten New Zealand

New Zealand is in a tectonically active part of the roaring forties and is vulnerable to a wide range of natural hazards. Yet, the threats of a tsunami in New Zealand are underrated, according to the latest report from the Natural Hazards Centre.

Over 40 years have passed since the last major tsunami hit New Zealand, and there is little awareness of the damage a tsunami could cause or how to respond to warnings, reports Natural Hazards Update, the Centre’s new newsletter, which was published today.

On 23 May 1960 a magnitude 8.5 earthquake in southern Chile generated a tsunami that swept across the Pacific, causing a major loss of life in Chile, Hawaii, and Japan. Although no deaths or injuries were recorded in New Zealand, there was widespread damage to coastal facilities and small boats. Thousands of people were evacuated, making it the largest ever evacuation in New Zealand history.

At the time there were widespread reports of people ignoring the warnings and going to the coast to get a better view of the approaching tsunami. This could have been disastrous.

“After the event there was much discussion in the newspapers of the need to improve the warnings and public awareness of the threat. These issues are still relevant today,” the report said.

Tsunami are just one of the natural hazards we face. Others being identified by the Natural Hazards Centre include storms, floods, droughts, landslides, earthquakes, volcanic eruptions, and coastal erosion.

The Institute of Geological and Nuclear Sciences (GNS) and the National Institute of Water & Atmospheric Research (NIWA) established the Natural Hazards Centre to inform New Zealanders of the extent of these threats.

“We want to strengthen the links between scientists, policy makers, planners, and emergency managers by providing a focal point for science-based information on natural hazards,” the report said.

The scientists’ knowledge is supported by a nationwide monitoring network recording sea level, seismic and volcanic activity, climate, and hydrology.

Large tsunami – like the ones that struck Papua New Guinea recently – may be infrequent, but they are usually catastrophic, which means the risk of damage and loss of life is substantial for low-lying coastal areas. Smaller tsunami of about 1 m are more frequent, occurring somewhere in New Zealand about once every 10 years, but if they coincide with a high spring tide or a local storm, they can cause significant damage.

Recent marine geological research by GNS and NIWA on New Zealand’s east coast continental shelf and north of the Bay of Plenty has produced some spectacular images of the seafloor and provided the means to identify potential local tsunami threats from submarine landslides, fault ruptures, and volcanoes.

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