By Samantha Simon
[email protected]
The Lesser Antilles are no stranger to seismic activity.
The island chain is a subduction zone, where plates converge, making the region susceptible to geo-hazards like earthquakes and volcanoes.
Thankfully, most of the thousands of earthquakes recorded annually go unnoticed, but the region remains at risk of moderate to significant events that can impact communities at any given time.
In response to the evolving seismic landscape, the UWI Seismic Research Centre has updated its earthquake alert system.
The centre’s Director, Dr Erouscilla Joseph, explained that the increase in reporting seismic events isn’t due to an influx of activity but rather as a precautionary measure, as preparedness efforts must be in place to mitigate the impact of such events.
The threshold for reporting earthquakes has been adjusted to include magnitudes of 3.5 and above in the Eastern Caribbean, leading to more frequent earthquake alerts online.
Amidst these seismic concerns, the submarine volcano Kick ’em Jenny off the coast of Grenada experienced a period of unrest in early February.
While the volcano’s activity may not trigger tsunamis due to its depth of only 180 metres, Dr Joseph pointed out that there are other risks to consider.
Although the risk of smaller tsunamis remains localised to surrounding islands like St Vincent and the Grenadines, boaters and marine interests in the wider region should remain vigilant.
The degassing process of the volcano can lead to a loss of buoyancy in surrounding waters, increasing the likelihood of boats sinking.
Additionally, the release of volcanic projectiles presents another hazard, alongside potential volcanic earthquakes and ash fall.
Dr Joseph also noted that there are active zones in the region which can present a concern.
“There are several active zones in the Caribbean that can generate regional tsunamis and the Puerto Rico Trench is one that comes immediately to mind.
“Forecasting can be compared to meteorology, where you have returns of flooding events or tropical storms or hurricanes with a return interval of X years, and they give statistics with what is expected in the hurricane season with the number of storms that will be a certain strength,” she explained.
She went on to explain that, like in meteorology, whilst they can look at records and point out that a large seismic event may not have occurred within the last century of two, they are not yet able to predict the exact time when such an event may occur.
Thus, the risk of a seismic event exists, as the region continues to experience thousands of smaller events each year, with larger events possible at any time.
