Still on the theme of earthquakes and their effects: I learned some fascinating stuff while researching my article for Wild Tomato. A conversation with Prof. James Goff, director of the Australian Tsunami Research Centre at UNSW in Sydney was a highlight.
Professor Goff and his students have been looking for traces of ancient tsunamis in the Nelson region, including the Abel Tasman National Park. They look for areas where marine deposits washed up by a tsunami would not have been obliterated, e.g. by a meandering river. Once found, these deposits can be dated by studying their contents. For example, a list of the remains of various marine organisms found in a sample can help to provide a ‘date stamp’.
Moawhitu, the bay shown in the photograph above taken on my return from a fishing trip last weekend, is of special interest. It’s at the northern end of Greville Harbour, on the western side of D’Urville Island. There was once a thriving Maori settlement here, on the flat land behind the beach. That suddenly changed.
Professor Goff and his team have found deposits from a tsunami which date from around 1450, up as high as 40m above the present sea level. Prior to 1450, there is apparently plenty of archaeology found in that area down near sea level. After that, there is nothing. All of the more recent items, dating from after 1450, are found at a much higher elevation.
The findings fit well with Maori history for the region. In their book “Te Tau Ihu o Te Waka: A History of Maori of Nelson and Marlborough”, Hillary and John Mitchell describe a disaster at (Greville Harbour): “a massive tidal wave called Tapu-arero-utuutu swept into the harbour and drowned almost everyone, tumbling their bodies into the sand dunes which were piled up by the force of the waves.” John explained to me that the area is still tapu ( ‘off limits’) to Maori.
Such waves were often attributed to ‘taniwha‘, mythical beings that lived in caves, the water or sea. They could be benevolent guardians or dangerous, predatory monsters. Thinking of the shocking images of that black, rolling monster sweeping across the fields at Sendai after the March Tohoku earthquake in Japan, ‘taniwha’ seems a very appropriate description.