SA measures four earthquakes

2010-04-22 20:03

kalahari.com

  • Pirates of Polokwane
    The 13th annual collection of Zapiro cartoons from the Mail& Guardian, Sunday Times and Independent... Now R126.00
    buy now
Johannesburg - Four earthquakes were recorded around Gauteng, the North West province and Limpopo on Wednesday, the Council for Geosciences reported on Thursday.

The first was at 13:28 in the Gamoep area of Limpopo and measured 2.4 on the Richter scale, with a depth of 5km.

The second earthquake was at 19:.34 in Gauteng, along the Roodepoort mining belt, west of Johannesburg. It measured 2.4 on the Richter scale and was recorded with a depth of 2km.

Patrick Malaza, chief financial officer at Rand Central Gold mines said they felt nothing and operations had not been affected.

"I didn't even spill my coffee," he quipped.

However, that quake solicited a number of calls to the council by worried residents around Johannesburg wanting to know what was happening.

A third earthquake was recorded in the area of the West Rand gold mines in the North West at 23:42, measuring 2.9 with a depth of 2km.

A fourth was recorded at 23:49 in the same area, measuring 2.9 with a depth of 2km.

Increase in quakes

Michelle Grobbelaar, manager of the seismology unit at the council said on Thursday there had been an increase in quakes in the Johannesburg region, which they are trying to get to the bottom of.

"We have been noticing it not just through our measuring, but also through the public phoning us to tell us about them," said Grobbelaar.

Grobbelaar said the council is trying to increase the number of seismograph stations in the Johannesburg area, and encourage the public to fill in their online questionnaire to let them know about an event.

Their initial feeling is that the quakes are related to mining activity and the number of abandoned mines in Johannesburg. Eighty percent of the region's quakes occur in gold mining areas.

The build up of stresses in the earth's crust needs to be released along a weak point and where areas have been excavated, there are empty spaces where there used to be rock.

"If you have excavated all that solid rock and have empty spaces, the earth has to accommodate for that," said Grobbelaar.

Earthquakes could also occur in areas where dams or reservoirs have built on spaces where there was originally nothing, putting tons of water onto the land mass.

"This creates stresses and lubricates the faults, now we have faults that can move."

Records

Equipment to measure earthquakes was only installed in South Africa in the 70s so researchers are trying to find ways of gathering older written records like journals to find out whether they are getting bigger or smaller in South Africa.

With the tragic images of the Haiti earthquake still fresh, Grobbelaar said that South Africans should not panic about a similar occurrence here.

"Generally, a 2.8 shouldn't cause any structural damage. But in the 3's you can expect more structural damage."

"In gold mines if the guys are down there, that's pretty serious."

Spokespeople for other mines in the quake areas were not immediately available to say if they had been affected, but during parliamentary questions, Mineral Resources Minister Susan Shabangu said "fall-of-ground" accidents remained the predominant cause of deaths in the industry.

Grobbelaar said South Africa was blessed with "modest" seismicity compared with countries like Japan or Chile.

Asked whether Wednesday night's quakes could be a predictor of something more serious she said: "I don't think people should be worried. We are looking into the Johannesburg ones though, because there is an increase."

"The others are running their normal course, it's to be expected."

To report an earthquake in your area contact the council at 012-841-1911 or complete a questionnaire on their website.
- SAPA

Read more on:    polokwane  |  mafikeng  |  johannesburg  |  earthquakes
NEXT ON NEWS24X

SHARE:

Read News24’s Comments Policy

 

Inside News24

 
/News
 
Traffic
Lottery
 
  • Wednesday Newlands - 09:17 AM
    Road name: M3 Northbound
    DELAYS approaching the Rhodes Avenue exit
  • Wednesday Cape Town - 09:08 AM
    Road name: N2 Inbound
    DELAYS between the N7 Highway and the M5 Highway Interchange
 
More traffic reports...
 

Jobs in Cape Town [change area]

Property [change area]

Travel - Look, Book, Go!

Magical Massinga

Spend 5 nights at the gorgeous Massinga Beach Lodge in Mozambique and only pay for 4 from R13 220 per person sharing. Includes return flights, accommodation, transfers and romantic turndown. Book now!

Kalahari.com - shop online today

Up to 60% off - clearance sale!

Save up to 60% on appliances, books, electronics, toys, movies and more. Offer valid while stocks last. Shop now!

Deal of the Week!

Get bestselling John Green novels now just R99 each! Hurry and get yours while stocks last. Shop here.

Mind blowing deals on beauty & fragrances

Save up to 30% off beauty and fragrances. Offer valid while stocks last. Shop now!

Up to 50% off hair care products!

Save up to 50% on professional hair care products at kalahari.com. Offer valid while stocks last. Shop now!

30% off academic books

Score a mind blowing 30% off academic books! Offer valid while stocks last. Shop now!

OLX Free Classifieds [change area]

Samsung Galaxy s4

Mobile, Cell Phones in South Africa, Western Cape, Cape Town. Date October 24

Best bargain in big bay

Real Estate, Houses - Apartments for Sale in South Africa, Western Cape, Cape Town. Date October 25

VW Golf 6, 1.6 Trendline (Excellent condition)

Vehicles, Cars in South Africa, Western Cape, Cape Town. Date October 25

Nokia E6

Nokia E6 has 8-megapixel digital camera with autofocus and built...

From R2599.69

I'm shopping for:

Horoscopes
Aquarius
Aquarius

It is always easier to look out and see what needs changing. Looking in is a lot harder... Today you may need to look at what...read more

There are new stories on the homepage. Click here to see them.
 
English
Afrikaans
isiZulu

Hello 

Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.


Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.

Settings

Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.








Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.