Head of the Earthquake Unit at the University of the West Indies, Mona, Professor Simon Mitchell says Sunday’s magnitude 4.6 tremor should serve as a wake-up call to the island’s vulnerability to the unpredictable nature such disasters pose.
Speaking exclusively with Jamaica Today at the Department of Geography and Geology, which he also heads, Professor Mitchell said that while he doesn’t want to induce the scare factor, Jamaica is still at a risk for even stronger earthquake events.
“We would see potential earthquakes of up to a 7.0 or a 7.2 as possibilities for Jamaica. We have had big events in the past, which means we will get big events in the future. There is no doubt at some point we will have a big earthquake in Jamaica,” he argued.
In his expert opinion, Professor Mitchell asserted that as the island sits near two active tectonic boundaries, the North American and Caribbean plates – which move against each other at a rate of two centimetres per year – the stress that builds up along the boundary is bound to be released eventually.
Sunday’s quake still wasn’t the strongest in recent times as the island recorded a magnitude 5.0 in 2005 (Aenon Town in Clarendon) and a 5.2 in 1993 (Kingston & St. Andrew).
Mitchell said that while most Jamaicans were lucky to have not suffered any infrastructural damage during Sunday’s earthquake, it still serves as an awakening to the realistic dangers posed by quakes.
“I think it’s very important that we have a wake-up call because it will make people realize that we are at risk of these earthquakes and it makes people think about what they’re going to do when we do get an earthquake,” he added.
Professor Mitchell said that hypothetically, any magnitude above 5.3 could pose a serious test to the limits of what cities such as Kingston and Montego Bay could withstand.
“We’ve known from previous [events] that 5.3 is about the limit before things start happening. Above 5.3, if we get to a 6.0, we’re going to have some problems; if it’s higher than that we’re going to have more problems. It also depends on what the weather’s been doing. Wet soils yield more potential damage than when we have dry soil because water reduces the ability for the rocks to withstand the waves coming through,” Mitchell told Jamaica Today.
So much so, Mitchell argued that if Sunday’s earthquake took place hours after the remnants of tropical depression Isaac soaked the island, things could have been much different.
“With the earthquake a couple days ago, it was a good thing it came at the start of the rains rather than later – potentially we could have had some landslides,” he added.
Mitchell posited that what worries him is that since 1907, when Kingston was last truly tested by an earthquake, many structures including the Mona Reservoir and Hermitage Dam have been erected and serious damage to them may exacerbate the fallout from future quakes.
“If you think about it, the last time Kingston was tested was more than 100 years ago [in] 1907. Think about the major things we’ve built in that time: The Hermitage Dam and Mona Dam, they’ve never been tested. So there’s a lot of places that have never been tested. If we have a 7.0, we’re going to lose a lot of lives, there’s no doubt about it,” Professor Mitchell said.
Apart from Kingston, other similar geological locations highly vulnerable to earthquakes include: Spanish Town, Montego Bay, Portmore, Linstead, Ocho Rios, May Pen and Savanna-La-Mar.