Experts probe 'mini tsunami'
2008-08-25 07:55
Cape Town - A mini tsunami may be the reason for the sudden rise and fall of the sea level along the West Coast over the last few days.
The National Sea Rescue Institute (NSRI) received reports that the sea level in Hout Bay, St Helena Bay, Saldanha Bay and Lambert's Bay changed suddenly three times on Thursday.
In Hout Bay, the water level first fell by a metre and then rose again by the same amount in the space of 20 minutes.
Factories were damaged by the high waves in St Helena Bay.
The NSRI called in the help of Geoff Brundrit, a retired professor of the University of Cape Town's Oceanography Department, to help investigate the phenomenon.
Seismic activity
Brundrit said the readings of a hydrographic monitor in Walvis Bay indicated seismic activity in the Atlantic Ocean, which could cause a tsunami.
Volunteers at the NSRI office in Mykonos also reported a phenomenon known as Proxigean Tide, which can lead to flooding.
Experts expect the next tide of this nature on December 12.
NSRI spokesperson Craig Lambinon said they were waiting to receive the readings on the hydrographic monitors in Luderitz, Port Nolloth and Saldanha Bay to see whether those monitors gave similar results to the Walvis Bay and Simon's Town hydrographic monitors.
"We are also waiting to hear from Ascension Island, St Helena Island and Rio de Janeiro to find out whether they have experienced similar circumstances.
"No one has been injured or killed. We have not been informed of any major damage but we believe that what was experienced on the West Coast on Thursday was a mini tsunami," Lambinon said.
Southern, Eastern Cape affected
There is also a possibility that the mini tsunami could affect beaches in the Southern and Eastern Cape, Tisha Steyn reported.
"There was abnormal movement in the water on Saturday," Ray Farnham said on Sunday.
"If you don't specifically look at it, you won't see it. There was a warning that the water level would be different to that given in the tide table, but it's nothing serious."
For example, if it was supposed to be low tide at 12:00, it was low tide but there were fluctuations.
"There were also larger swells, as if a large ship was travelling past, but we were unable to determine what caused it.
"No damage occurred."
The heads of the NSRI stations in Witsand, Stillbaai, Mossel Bay and Wilderness did not notice anything unusual.