The big bang theories are theories no more.
A large noise and accompanying ground shaking that occurred on the southern end of Seven Mile Beach last Wednesday afternoon had residents wondering what was going on.
In the end, the rattle and bang came from a rather common source: excavation blasting.
‘Blasting occurs here once or twice a week all year round,’ said Peter Ogden, engineer of major projects for Public Works.
The blast, carried out by Midland Acres Ltd. with approval from the Public Works Department was done in preparation for the excavation of a canal at the Dart project off of the Esterley Tibbetts Highway.
The theories of the bang’s origin were much more exciting though, with curiosity of the mystery prompting a communication with the Caymanian Compass.
Because of the shaking, some thought it was an earthquake.
Because of the loud noise, some thought it was a gas explosion.
Others thought an accident involving a truck caused the bang.
Paul Tibbetts of Cox Lumber on Eastern Avenue had a different thought.
‘I was walking down the stairs when I heard it, and just thought it was loud thunder,’ he said.
Brian Eccles of DDL Studio Ltd. at Buckingham Square said he did not know what bang was.
‘We heard it and saw that it rattled the walls and windows’ he said. ‘We all looked up at each other, and then carried on with our work.’
Sebastian Guilbard, the Campus Manager at the Residence Hall of St. Matthew’s University School o f Medicine came the closest with his big bang theory.
‘I thought it was some kind of mining involving explosives,’ he said.
The blast was heard and felt at least from Kirk’s Supermarket to the south to Buckingham Square to the north and occurred at 3.30pm.
Public Works’ Mr. Ogden said the scope of Wednesday’s blast was not particularly excessive for a canal excavation, and he was somewhat perplexed at the extent of the range it was heard.
‘Maybe the current lack of trees has something to do with it,’ he said, noting that vegetation would muffle the sound.
He also said the direction of the wind also contributes to hearing a blast.
Mr. Ogden said the blast did not occur as one single event, but with groups of charges going off 1/25,000 apart.
He theorized that if enough groups of charges were triggered, the cumulative time lapse might have created a more substantial earth shaking event.
Mr. Ogden noted that the blast was done to a layer of rock that was underneath peat, which created ‘a nice soft cushion’ above the explosion.
Apec Consulting Engineers said it set up two seismographs to monitor the blast, one located at the West Indian Club Nursery and one at the Britannia Golf Course.
Neither seismograph registered any reading, according to Apec.
‘Therefore, the resultant peak particle velocity produced by the blast did not exceed the trigger level of 0.02 inches per second,’ the company said.
Denis Murphy of Apec said that people could have been feeling percussion waves as opposed to ground movement waves.
He said Apec has been monitoring blasts at the site for quite some time.
‘We may have just encountered a particularly strong vein of limestone rock,’ he said.
No damage was reported to any structures as a result of the blast.
John Papesh, vice president of marketing and public affairs for Dart Realty said the blasting was all of the development process.
‘We’re very cognizant that we have to go through some critical construction processes,’ Mr. Papesh said. ‘We’ve gone to great lengths to ensure that all the proper procedural methods are observed.’