Active Planet: Over the last two days, scientists record 373 earthquakes – Jamaica’s 7.7 the strongest of 2020

Over the last two days, the planet has churned out over 300 earthquakes, BUZZ fam!

The University of the West Indies’ (UWI) Mona Geoinformatics Institute has disclosed that around the world, a staggering total of 373 earthquakes struck within the last 48 hours – with the massive 7.7 magnitude temblor that rocked off the coast of Cuba and Jamaica, being the strongest since the start of 2020.

To say the northern Caribbean dodged a bullet on Tuesday (Jan. 28) is a massive understatement as the quake struck around 2:10 pm, 72 miles northwest of Lucea, Hanover – its location playing a major difference in the fallout from the seismic activity experienced.

By many standards, yesterday’s earthquake could have been much more devastating, as experts determined that the tremor had 20 times more amplitude and 60 times more power than the 6.4 magnitude event that damaged sections of Puerto Rico earlier this month.

Location of yesterday’s massive 7.7 magnitude earthquake

The powerful quake triggered a series of aftershocks that continued to rattle sections of the Cayman Islands, Cuba and Jamaica – as recently as 9:51 am on Wednesday, when a magnitude 5.1 was recorded by the US Geological Survey (USGS) 129km northwest of Montego Bay.

Matters were made direr as the International Tsunami Information Centre notified sections of the Caribbean to be on alert for tsunamis, triggering mass-evacuations in the Cayman Islands, Cuba, Jamaica, Belize and as far away as Miami, Florida.

Geologically, the region, based on the nature of its seismic activity (being transform plate boundaries), can’t get many earthquakes stronger than Tuesday’s magnitude 7.7 earthquake but with respect to the Caribbean’s rock composition and structure, many nations would struggle to withstand even a magnitude 6.

Take the Cayman Islands for example. Yesterday’s earthquake is a major wake-up call for the UK dependency as many of its structural inefficiencies have been exposed by the 7.7 tremor.

Several minutes of shaking reduced sections of the capital Georgetown to nothing but sinkholes and sloshing seawater as frightened citizens watched powerlessly.

The city was built with real estate and aesthetics in mind – putting structural integrity at the back burner – a decision that will come to cost the islands sooner rather than later.

The situation, though somewhat different, could play out just the same in Jamaica.

The island’s largest cities and towns, apart from Mandeville, all sit near the coast or along alluvial deposits positioning millions of people on unstable foundations amid seas of concrete and steel.

A simplified geological map of Jamaica, showing the locations of the Cretaceous inliers (Photo: ResearchGate.net)

The ghost of the magnitude 7 earthquake that levelled Haiti still haunts that country a decade later and the last two major tremors that struck Jamaica in 1907 (Kingston, magnitude 7.4) and 1692 (Port Royal, magnitude 7.5) paled in comparison with yesterday’s record-breaking quake.

Structurally, many lessons have been learnt from Jamaica’s two great earthquakes, with most developments being tasked to adhere to strict building codes.

What remains to be seen, and it’s the hope we never do, is how well our buildings cope under extreme stress.

The scary part is that the Earth is not our friend, and it will not hesitate to remind us who’s in charge.