Windhoek — AN earthquake measuring 5,6 on the Richter scale shook the Erongo Region at 09h15 on Friday, with tremors felt as far afield as Windhoek.
It was the strongest recorded earthquake in Namibian history, according to seismologists. According to Dr Gabi Schneider, Director of the Geological Survey of Namibia (DGSN), readings from various stations have identified the earthquake's epicentre as somewhere between Khorixas and Omaruru (latitude 20,7 south and longitude 14,1 east).
She said most seismological stations around the world recorded the event. "The event is believed to have been caused by the faults southwest of Khorixas. It was felt in Walvis Bay, Swakopmund, and as far as Windhoek. I believe the earthquake, which originated at the Etendeka plateau, was amplified at the Karoo-based areas (South) and the Namibia margin (West) and diffracted at the Khomas complex," Schneider explained.
She said it was the strongest earthquake ever recorded in Namibia. "This means that an event of this magnitude is above the threshold size 5 expected in Namibia. We can say that an earthquake of magnitude 6 can happen in the region," she said.
On Friday morning a deep rumbling shook the town of Swakopmund and members of the public called The Namibian's coastal office to enquire whether there had been an explosion at the town.
Residents from Vineta, about 5 km from Swakopmund's town centre, called in and asked: "Did you feel that?" Others phoned in to tell what they experienced. "I ran to my manager to ask him if we need to get out of the building because it seemed to be getting worse," one woman said. "It was quite hard," said a Vineta man.
"It was eerie. I thought things were going to fall off the building," said Rod Braby of the Namibian Coast Conservation and Management (Nacoma) Project.
Some residents even speculated that it may have been the effects of NDF military exercises conducted in the dunes between Walvis Bay and Swakopmund last week, or a blast at one of the local mines.
People called in from as far as Henties Bay and Uis. "It felt like a massive compactor," said a Henties Bay businessman. Martie Duvenhage, of Brandberg Restcamp, said he heard a loud explosion before everything started rattling.
"It sounded and felt like a thousand people running on our roof," she said. A woman from Uis sent an e-mail stating that she was "still shaking" out of shock. "I thought our house was going to fall on us. The earth started rumbling and shaking and things started falling off shelves. My first thought was that it was an airplane that crashed into our home," she said.
A teacher at Omaruru's Martin Luther School, Ringo HoÃ«seb, said classes were evacuated as soon as the tremors started. "There was first a small tremor, and then a big one followed," he said. "We did not want the building to fall on the children."
Residents at Usakos and Khorixas said the earthquake lasted "for a lengthy period". No damage was reported at the time. Namibia has experienced several earthquakes over recent decades. In 1952 an earthquake of 5,5 on the Richter scale was measured at Keetmanshoop.
In April 2008 the Omaruru area experienced an earthquake of 5 on the Richter scale. And the Kamanjab seismological station records a "few tremors" every month.
"The geological survey is planning to closely monitor the seismicity in the Erongo Region by increasing the number of stations in the area," Dr Schneider said.