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Tsunamis can be different from what you imagine

By Stan Stewart

At the time, Mark was 8 years of age. The Chile earthquake was the largest earthquake recorded in the 20th century. It caused huge devastation and loss of life in Chile and across the Pacific. The tsunami it created travelled at 200k per hour. However, by the time it reached Whitianga it was different.

At the time of the tsunami, Shirwin Lee was in his early 20’s and his cousin Robin Lee was in his mid 20’s. Neither Shirwin nor Robin can remember how they heard of the Chile earthquake and the predictions that a tsunami would hit our coast. Both are certain that the Fire Brigade was involved in some way. Certainly, people had radios, large units, but there were no portable radios except for car radios.

People knew something would happen in the Mercury Bay area, but no one was sure what. One of Shirwin’s most vivid memories was going to the BNZ bank (the only bank in town) and seeing the vault open and the staff feverishly putting everything – money and documents etc into the vault. The expectation was that the tsunami would sweep through and flood the town. This didn’t happen. Water entered some houses at Brophy’s Beach and one of the hangars at the airport was flooded. However other buildings and the roads were not affected by wave surges.

There were no huge waves. What did happen was that the sea rose and subsided every twenty minutes. This change in sea level was enormous. The normal tidal fluctuation was around 6ft. The tsunami surges happened about every 20 minutes and the seal level changed by about 20ft. This meant that when the tide rushed out it revealed the sea floor at the pier and when it came in, it lapped over the deck of the pier. This had never happened before and it has never happened since.

People reacted to the news of the coming tsunami in different ways. A large group went up the hills at the back of the town, (Centennial Drive region). A number went to higher ground on Lee’s farm at the back of the town. One family stayed up there for more than a week. A couple packed their car with essentials and their budgerigar and sat at Brophy’s beach. Everyone was waiting for the ‘big’ wave. It never arrived.

Boats in the estuary were pushed around by the rising and falling water levels. A number lost their moorings. As far as we know none of the boats were destroyed.

For a few days, all of the buildings in town were locked up and the town was deserted. Some young men forced an entry into the hotel. Once inside they availed themselves of the booze. It seems their rational was ‘the town is doomed’ and we might as well drink until disaster hits. It never hit. No one is quite clear as to how this episode ended.

With reference to future tsunamis, the consensus seems to be this. The shape of the Whitianga harbour is such that huge waves are broken up before they reach the harbour. The sea close to the Whitianga wharf and Buffalo Beach is at right angles to the open ocean which has the effect of dampening monster seas. Warning: This is just beach-talk so don’t take it as a scientific prediction.

Caption: 1960 Tsunami damage to a Pacific Island. By the time it reached NZ it was only .5 of a metre high.

 |  The Informer  | 

By Stan Stewart

At the time, Mark was 8 years of age. The Chile earthquake was the largest earthquake recorded in the 20th century. It caused huge devastation and loss of life in Chile and across the Pacific. The tsunami it created travelled at 200k per hour. However, by the time it reached Whitianga it was different.

At the time of the tsunami, Shirwin Lee was in his early 20’s and his cousin Robin Lee was in his mid 20’s. Neither Shirwin nor Robin can remember how they heard of the Chile earthquake and the predictions that a tsunami would hit our coast. Both are certain that the Fire Brigade was involved in some way. Certainly, people had radios, large units, but there were no portable radios except for car radios.

People knew something would happen in the Mercury Bay area, but no one was sure what. One of Shirwin’s most vivid memories was going to the BNZ bank (the only bank in town) and seeing the vault open and the staff feverishly putting everything – money and documents etc into the vault. The expectation was that the tsunami would sweep through and flood the town. This didn’t happen. Water entered some houses at Brophy’s Beach and one of the hangars at the airport was flooded. However other buildings and the roads were not affected by wave surges.

There were no huge waves. What did happen was that the sea rose and subsided every twenty minutes. This change in sea level was enormous. The normal tidal fluctuation was around 6ft. The tsunami surges happened about every 20 minutes and the seal level changed by about 20ft. This meant that when the tide rushed out it revealed the sea floor at the pier and when it came in, it lapped over the deck of the pier. This had never happened before and it has never happened since.

People reacted to the news of the coming tsunami in different ways. A large group went up the hills at the back of the town, (Centennial Drive region). A number went to higher ground on Lee’s farm at the back of the town. One family stayed up there for more than a week. A couple packed their car with essentials and their budgerigar and sat at Brophy’s beach. Everyone was waiting for the ‘big’ wave. It never arrived.

Boats in the estuary were pushed around by the rising and falling water levels. A number lost their moorings. As far as we know none of the boats were destroyed.

For a few days, all of the buildings in town were locked up and the town was deserted. Some young men forced an entry into the hotel. Once inside they availed themselves of the booze. It seems their rational was ‘the town is doomed’ and we might as well drink until disaster hits. It never hit. No one is quite clear as to how this episode ended.

With reference to future tsunamis, the consensus seems to be this. The shape of the Whitianga harbour is such that huge waves are broken up before they reach the harbour. The sea close to the Whitianga wharf and Buffalo Beach is at right angles to the open ocean which has the effect of dampening monster seas. Warning: This is just beach-talk so don’t take it as a scientific prediction.

Caption: 1960 Tsunami damage to a Pacific Island. By the time it reached NZ it was only .5 of a metre high.