AN abnormally high tide was reported along South Africa's west coast on Thursday, according to South African news reports. Oceanographers in that country are investigating the cause of what was described as a "mini-tsunami", during which sea levels rose and fell about a metre higher and lower than average. Craig Lambinon of South Africa's National Sea Rescue Institute (NSRI) in Cape Town told The Namibian on Monday that although the surge was minor, it had caused damage. At St Helena Bay, a car was pulled into the sea and some factory buildings suffered damage. Lambinon said the NSRI had asked Geoff Brundrit, a retired professor of the University of Cape Town's Oceanography Department, to investigate the phenomenon. "We hope to hear from him soon to see if the surge was due to weather or seismic activity under the ocean," he said. According to him, hydrographical readings at Walvis Bay indicated seismic activity in the Atlantic Ocean. Walvis Bay and Luederitz are apparently the only two locations in Namibia where hydrographical monitors have been placed - the readings are fed directly to the South African Hydrographic Centre in Cape Town. There were reports that the "mini-tsunami" was caused by a "massive underwater landslide" offshore from the Orange River, but Lambinon said it was too early to say what the real cause was. A Namport source at Walvis Bay told The Namibian that there was no sign of a surge at Walvis Bay or Luederitz.
"If there was something, our phone lines would be ringing red hot," the source said. The source said if there had been abnormal rises and drops in the sea level it would have affected port traffic. He said large, fully loaded cargo ships entered the port at high tide to avoid hitting the ocean floor. "If a heavy ship did come in, and the tide dropped [by about a metre], especially when the tide was going out, then we might have experienced problems. But nothing like that was reported," the source said. Riaan Burger of Namdeb at Oranjemund also said nothing was detected there. He said a rise or drop of about one metre would not be a major problem to Namdeb's mining operations. "Rough seas during a spring tide would be more of a concern to us," he told The Namibian. Ciaran MacDevette, Assistant Tidal Officer at the Hydrographic Centre in Cape Town, confirmed the incident. "Unfortunately we are not able to draw any conclusion since the incident is being investigated," he said. "There was however anomalous tidal activity - the readings were different to stormy conditions and similar to the small surge that followed the South East Asia Tsunami in 2004, which could also be felt along South Africa and Namibia's coastline a couple of weeks later." He said in general such a small fluctuation would not be detected with the naked eye, except where people lived along the beach and were familiar with the shape of their shoreline during normal tide variations.)
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