JAMAICANS felt the ground shake 19 times last year, five times more than they did a year earlier.

And, by the Earthquake Unit’s count, this was just a fraction of the total number of earthquakes recorded in 2024, which stood at more than 670, with 310 of them being local events.

Amid the seeming increase in felt earthquakes, at least over the last four years — seven in 2021; eight in 2022; 14 in 2023; and 19 in 2024 — it is understandable that some Jamaicans are wondering if the country should be bracing for a big one, especially those who were jolted from their sleep at 1:00 am when the near-region magnitude 6.1 quake rocked sections of the island on December 23 last year.

But research fellow and head of the Earthquake Unit Kevin Tankoo told the Jamaica Observer that though, for decades, it has been touted in the scientific community that the Caribbean country is, in fact, due a big earthquake, there is no way of pinpointing when it will occur.

“Globally, the science has not got to the stage of being able to predict. You have probably isolated studies which may look at certain elements, but it is very difficult to make that relationship, to pick a trend or to pick some trigger,” he said, adding that most things are done post-analysis.

“However, from recording the data or recording seismicity, we are able to understand which faults are active, [and] when you combine that with your understanding of the geology or local tectonics, you can then [say] these faults are active, these were previously active and you sort of build up your history from that,” Tankoo told the Sunday Observer.

With this approach, the head of the Earthquake Unit said experts can understand which areas are likely to experience another earthquake.

“Again, this is largely based on history and our macroseismic hazard for Jamaica, and we know that eastern Jamaica… based on the 1692 and 1907 earthquakes, these areas are likely to experience a larger earthquake. The 1957 [earthquake], however, was in Montego Bay, closer to the western part of the country, and again, our records are not as detailed as some of the longer-standing countries, so you can’t really tell a trend, but you can understand which areas are more likely [to have an earthquake],” Tankoo said, adding that it is called the probability of exceedance, which is the likelihood of a certain fault to actually rupture across a certain time frame.

The earthquakes to which he referred were the Port Royal quake of June 7, 1692, with the most extensive loss of life happening in Port Royal, where a portion of the town sank into the sea; the great Kingston quake of 1907 that resulted in more than 1,000 deaths; and the March 1, 1957 earthquake that affected mostly western Jamaica.

He explained to the Sunday Observer that the often-referenced big earthquake that is said to be due is more in relation to when was the last time that a country had a big earthquake or one of a particular size.

“We know it’s over 100 years since 1907 that an earthquake of that magnitude occurred locally for us. So it’s based on that premise, and not necessarily based on any additional sort of solid data.

“But, globally, we’ve seen that seismic events reoccur, and it’s just a matter of pinpointing the time; it’s not something we can currently do with the science and the technology available,” Tankoo added.

However, since Jamaica is located in an active seismic zone, people’s concerns are not unfounded.

“It is common in the northern Caribbean, not just in Jamaica… because of that location between the North American plate, the Caribbean plate, a lot of those plates are moving, and because of those movements, that is what generates earthquakes.

“So it is something that, yes, we have to be concerned with because we live in an active seismic area, and historically we have had incidents where there have been significant damage — 1692, 1907, 1957 — these are all earthquakes of significance,” the head of the Earthquake Unit explained.

In fact, he added that the reason Jamaica commemorates Earthquake Awareness Month in January each year is because of the historical significance of the 1907 earthquake, which occurred on January 14 that year.

Reiterating that the country cannot predict what will happen, when or if Jamaica will experience more earthquakes or fewer earthquakes each year, Tankoo urged caution.

“The figures that we see in the previous years, it’s a combination of factors that would contribute to those figures — one of it being increased capacity for Jamaica to record seismic activity,” he said, adding that the Earthquake Unit has significantly improved its capacity and its coverage across the island and the team continues to build out the seismic network, particularly for detecting smaller earthquakes.

“And then number two, a lot of the local earthquakes, some of the larger numbers are actually aftershocks, so when you look at your entire record itself, you have to decipher aftershocks versus core events themselves. Because of that, you can’t really pick a clear trend to say over 10, 20, 30 years to say that this is what’s going on,” he added.

Of note, too, is that although there appears to be an uptick in the number of felt earthquakes in the last four years, the fifth year — 2020 — a total 701 earthquakes were recorded, with 209 of them being located in the local region and 18 being felt.

Besides serving as Jamaica’s hub for earthquake monitoring and seismic research, the Earthquake Unit also records blasts or possible blasts, which Tankoo explained are from mining or quarrying or any detonation.

Looking back at last year’s numbers and the 19 felt earthquakes, he explained that those reported as felt tend to be the larger magnitude earthquakes that might occur in closer proximity to places that may be populated. He noted that the Earthquake Unit also tries to understand the level of shaking at various points of the island.

“So we try to understand how intensity changes and so, for instance, an earthquake that occurs in eastern Jamaica, the intensity would be greater there than in western Jamaica. So this relationship helps us understand exactly how we can then go about preparing better or building and mitigating for particular areas of development.

“Historically, for Jamaica, we’ve seen mostly magnitude three and above, and again, depending on where it occurs and how deep it occurs, we might get a magnitude 2.8 or 2.9 possibly being reported as felt by just a few people.

“When you get into the threes, the fours, then you get more widespread reports of earthquakes being felt,” he said.

Research fellow and head of the Earthquake Unit Kevin Tankoo sat down for at interview at the Jamaica Observer’s Beechwood Avenue, St Andrew, headquarters recently. Photo: Karl Mclarty