Expert – Tremor, not earthquake in Jozi
JOBURG - Tremor in Johannesburg most likely from old mine shafts in Brixton, an expert at University of Johannesburg says.
UPDATE: 18 November 2.30pm:
A tremor shook parts of Johannesburg shortly after ten on the morning of 18 November.
NMT received reports of the tremor out of Fairland, Auckland Park, Emmarentia and Brixton.
“Everything began to shake very slowly and then it became more rapid,” one Emmarentia resident recounted.
“I could hear loud noises from the buildings shaking. It went on for about ten to fifteen seconds.”
According to Dr Herman van Niekerk, lecturer in structural geology at the University of Johannesburg’s Department of Geoscience, the tremor was most likely the result of old mine shafts collapsing.
The epicentre of the tremor was said to be beneath UJs Auckland Park campus, as the Council for Geoscience suggested, but Dr van Niekerk suspects that a more accurate analysis would find the tremor started at a nearby mine shaft.
“It is very difficult to come up with an epicentre because it takes a lot of reading data, but there are no old mine shafts underneath the university itself so it is highly unlikely,”he said.
“UJ may just have been used as it is a recognisable landmark. Now, if you go just over Brixton hill to the southern side of Brixton Ridge, there are many abandoned open mines. If these mine shafts collapse, they will obviously cause the place to shake.”
Dr van Niekerk reiterated that an earth tremor should not be mistaken for an earthquake.
“Southern Africa isn’t close to many platatonic boundaries or big fault zones where earthquakes usually happen,” said Dr van Niekerk.
Instead, when old mine shafts collapse they send shockwaves through the earth with the same effect as an earthquake even though they are formed due to different circumstances.
“Until we go around and find that half of Joburg has shifted fifteen meters to the left, we cannot call it an earthquake.”
UPDATE: 18 November 11.06am:
According to the Council of Geoscience this morning’s earthquake was measured as magnitude 4 on the Richter Scale.
Manager of the seismology unit Michelle Grobbelaar described the tremor as “quite a big guy”.
The preliminary analysis indicated the epicentre was near the University of Johannesburg just before 10:00.
According to Grobbelaar it’s a rule of thumb that another tremor of similar magnitude could be expected in the same region, but seismologists could not predict when this would happen.
Tshepo Motlhale, divisional chief for disaster risk management, said the tremor didn’t last for more than six seconds.
Motlhale said he experienced the “strong” tremor while he was in his office.
Details are still sketchy and an investigation is underway.
Help the Council for Geoscience determine the scope and cause of the incident by clicking on this link and submitting a Seismic Event Enquiry
18 November, 10.30am:
According to users on the social media site the tremors could be felt across the city and reports came in of shudders in Northcliff, Houghton, Rosebank, Illovo, Sandton, the CBD, Industria, Parktown, Randburg, Fourways and more.
@dieterbrandt tweeted: #Earthquake 09h55 #Johannesburg tremor just moved our building back and forth. The ground moves beneath our feet.
He wasn’t the only one as tweets came in fast regarding the tremors using the hashtag #Earthquake
@lewisc4rl: Haha I thought I was loosing my head hahaha #Jozi #EarthQuake
@TeboIsMyName: The earth Is shaking Here In Jhb #EarthQuake Is Coming? Huh
@DneoM: the south felt it 2! the mines are collapsing underground RT @iamsuede: Young Illovo Tremors? #EarthQuake”
@Michael_Scholtz: #earthquake just felt one in randburg. About 5 secconds. But felt like quite a big one.
@absolute_phil: Massive tremor just hit Bedfordview.#earthquake #tremor
@juanjvrensburg: #Earthquake in Fourways Johannesburg just now.
@djsivaksa: #Earthquake just hit Rosebank. Maybe its a sign that Rick Ross is also coming to SA soon.
@Ellaword1: Just experienced a mini #earthquakein@Sandton…yes in SouthAfrica!!!
@howesandrew: Just felt the ground shudder. #earthquake#tremor #johannesburg #sandton
There is no news yet on the cause of these tremors but we will be following this story closely.
Did you feel tremors this morning? Tell us your experience in the comments.
i was asking myself, do i run or do i just sit and wait to die because, where will i run to if im on 2nd floor in a big building in the JHB CBD
i was asking myself, do i run or do i just sit and wait
During our exam the ground started shaking! In South Africa/ Roodepoort
The tremous where quite faint in the South of Johannesburg, but my counterparts contacted me from Rivonia in fear of the possibility of our office building collapsing on them as it was much intense in that region!!!
Everyone doesnot believe me when i tell them I felt the earthquake, I am in Booysens,City Power, Johannesburg
I think jozi is in danger course it wil cum back again the will run back to plk
We felt the earth moving here in Maraisburg.
I was so afraid, thought that my life on earth will be ending today
Felt the earth tremor while writing my Afrikaans exam,,none of my classmates noticed but the one beside me did,,after the whole movement we looked at each other and started giggling..
I felt as if it was the end of me
Worse part I was writing exams then you
Could literally feel the class Glass windows
Shaking.
Yhoo that mini tremor woke me up while dreaming,I even thought it was gonna be a big dissaster…#Langlaagte#tremor
My friends didn’t believe me when I told them what happend..they did not hear nothing about it
#tremors in jozi#
Seems these tremors ddnt end on the 18th only_*just felt one now now
I too felt one an hour or so ago in bryanston. No one believes me though
Yes i did feel the tremor last night at Modimolle around 9pm and it lasted for 7 sec.