Seismic Shift

The 5.3 magnitude earthquake that jolted Jamaica early yesterday morning has raised the antenna of one of the country’s foremost geologists, Professor Simon Mitchell, who says the latest tremor moved onto the Wagwater fault.

The Wagwater fault, which is 1.5 to 2.5km wide, together with four other faults, controls the tectonics of the Blue Mountain Blocks.

“I’m not particularly happy about that because that’s a big structure in Jamaica and it probably hasn’t moved for maybe hundreds of thousands of years,” Mitchell told The Gleaner.

Mitchell said Friday’s earthquake shows a developing pattern over the last two years of them moving progressively across Jamaica in a westerly direction, and this worries him.

“So they started in St Thomas and then went to Portland and although that’s a bit north, they’re still moving westward and are now in St Andrew which suggests that the stress is being transferred from the east to the west,” said Mitchell, a professor of Sedimentary Geology at The University of the West Indies (UWI), Mona.

On Friday, the Office of Disaster Preparedness and Emergency Management (ODPEM) said the 5.3 magnitude earthquake struck in the northeast section of Jamaica at 8:01 a.m.

ODPEM said the Earthquake Unit at The UWI reported that the epicentre of the tremor was located 6 kilometres northeast of Golden Spring, St Andrew, with a focal depth of 27 kilometres and the intensity being felt across the island.

ADDITIONAL ASSESSMENTS

Mitchell said of major concern is the south coast fault which runs from southern St Elizabeth to St Thomas. He said stress may be building up on this fault system.

“That would not be a good situation because with earthquake you don’t have everything in front of you to work out,” the professor said.

Further, he said additional assessments are being made to confirm the 27 kilometres depth. He said if the earthquake, in fact, ran that deep it may mean some form of adjustment took place at the base of Jamaica’s crust.

He said Jamaica’s depth is approximately 25 to 30 kilometres.

Yesterday’s earthquake is the second major tremor felt in months, after a 5.6 magnitude one rattled Jamaica in October last year, shuttering schools, businesses and leaving rattled citizens scampering for safety.

That quake, which lasted approximately 30 seconds, had its epicentre 10 kilometres south of Buff Bay in Portland and was felt in eastern Jamaica and several other parishes.

kimone.francis@gleanerjm.com

EARTHQUAKE SAFETY TIPS

• Stay calm and, if necessary, help calm the people who are with you.

• If you are inside a building, get under a sturdy desk, cover your head and hold on… Duck Cover, Hold (DCH).

• Stay away from windows and from objects that could fall, such as loose electrical wires.

• If you need to evacuate, use stairs, not elevators. Go to a safe area.

• If you are trapped, try to strike a metal object to make noise.

• If you are outdoors, go to an open area away from trees, tall buildings, utility poles and wires.

• If you’re in a vehicle, pull over to the side of the road to keep it clear for emergency vehicles and stop as quickly as safety permits.

• Safely bring the vehicle to a stop away from electricity polls and overhead wires.

• Don’t stop on a bridge or close to buildings from which debris may fall.

• Avoid stopping near or under trees, overpasses and utility wires.

• Stay inside your vehicle, proceed cautiously once the earthquake has stopped, watching for road and bridge damage, fallen or falling objects and electric wires.

AFTER AN EARTHQUAKE

• Check the condition of your dwelling. If you consider it unsafe, notify the authorities and go to a temporary shelter, or stay with acquaintances or family members.

• Consult official sources to get the most up-to-date information.

• Be careful with electrical currents, propane/natural gas lines, and sources of chemical hazards.

• Help your family members and community by offering messages of support and encouragement.