Earth tremors: 'If it happens, it will happen again'
After Cape Town was rocked by earth tremors last weekend, a geophysicist has warned that it could happen again.
Professor Andrzej Kijko, director of the Natural Hazards Centre at the University of Pretoria, said if Cape Town were to be hit by a large seismic event, there would be major damage to the city’s infrastructure and property.
Last weekend, a 6.2-magnitude earthquake was detected roughly 1600km offshore in Cape Town, which was then followed by 2.5- and 2.9-magnitude tremors that were felt even in the Northern Suburbs.
“It’s doubtful that the epicentre of the earthquake would be exactly the same as previously experienced, but the rule of seismologists is very clear: If it happens, it will happen again,” Kijko said.
“We don’t know exactly when, but we do know the area. The easiest element for us to determine is where it will be. Were we to have a 6.3-magnitude earthquake in Cape Town, there will be severe damage.”
Kijko added that 90% of seismic activity in South Africa was caused by mining.
In 2014, Kijko co-authored a paper titled “A scenario approach to estimate the maximum foreseeable loss for buildings due to an earthquake in Cape Town” which estimated that should the city be hit by a 6.96-magnitude earthquake, deemed the “worst-case scenario”, there would be severe destruction to property.
The paper calculates this using two previous major earthquakes, a 6.3-magnitude quake in the Milnerton area in 1809 whose epicentre is estimated to be the site of the old Ascot Racecourse, and the 6.3-magnitude quake in Tulbagh and Ceres that claimed 12 lives in 1969.
In another estimation, damages from a 6.3-magnitude quake could result in damages to structures within a 50km radius of the epicentre which would cost the insurance industry up to R10billion.
According to insurance expert Christelle Colman, while South Africa’s insurance providers were aware of the risk of earthquakes striking the city, there were other factors to consider.
“If you have insurance with a South African insurance company, there’s a 100% chance you’re covered from damage.
“The big issue for us, and what we look at, is urban sprawl in the Milnerton, Parklands area where they expect an epicentre to be.
“It’s one thing to talk about being insured, but the majority of people that will be affected are those who have no insurance,” said Colman.
She added that the insurance industry could survive the multibillion-rand aftermath that Kijko envisaged.
“Each insurance company in South Africa has their own model and they determine their exposure according to the number of risks in a specific area, and then they would take those measurements to the reinsurance market.
The reinsurance companies would then reinsure the insurance company’s exposure on a catastrophe basis.”
On Monday, the City of Cape Town stated that in the event of an earthquake, the Council for Geoscience and the SA Weather Service would be the lead agencies.
“The City’s disaster co-ordinating team will co-ordinate responses to the potential impacts, involving both internal and external agencies including the SAPS, SANDF, EMS Urban Search and Rescue, SPCA, etc,” said mayoral committee member for safety and security JP Smith.
James-Brent Styan, spokesperson for Local Government, Environmental Affairs and Development Planning MEC Anton Bredell, said: “We believe our systems are in place in the event of a disaster.
“We’ve got more than 160 highly-trained people we can deploy if there is a situation.
“Over the past 10 years, we’ve sent teams to assist earthquake-struck places like Haiti and Japan.”