Climate Change Editor
seigonie.mohammed@guardian.co.tt
The newly uplifted coastline at Galfa Beach is providing scientists with rare geological evidence while highlighting the challenge of reconstructing an earthquake’s effects when no dedicated seismic monitoring instruments were in place to record what happened beneath the site.
Researchers from The University of the West Indies Seismic Research Centre (UWI-SRC) visited the area on Monday to investigate how last week’s powerful earthquakes off Venezuela may have triggered the dramatic changes now visible along Trinidad’s southwest coast.
Using seismic arrays and other geophysical instruments, the team is examining the area’s subsurface properties to determine whether Galfa’s geology amplified the long-period ground shaking generated by the magnitude 7.2 and 7.5 earthquakes that struck northern Venezuela within 39 seconds of each other.
“Our investigation today is just to characterise the site in terms of its geophysical properties,” said UWI-SRC researcher and field team lead Kafele Reddock. “We can calculate how thick those sediment layers are beneath the surface and see if they are what we would expect to be resonant with the characteristics of the earthquakes that we got in Venezuela.”
The investigation comes as visitors continue flocking to Galfa to see sections of the coastline that appear to have been pushed upwards, exposing new land that did not exist before.
Cedros residents from the Schneider family, who frequently visit the beach, said the change was dramatic.
“This piece of land we’re standing on right now was not here. It was just a narrow piece of sand and rock ... all this didn’t exist before.”
Although the physical changes are evident, scientists say determining exactly when they occurred remains a challenge.
“We cannot tell if it happened suddenly because of that earthquake or if it’s related to other earthquakes,” Reddock said. He explained that researchers are retrieving data from a seismometer in Cedros to determine whether smaller local earthquakes also occurred.
While the Cedros station can detect nearby activity, Reddock said identifying the precise location of any small seismic events requires a network of instruments.
“In seismology, you need three sensors to detect the event and locate it, and we only have one in this peninsula,” he said, noting that scientists are therefore combining field observations with available seismic data to reconstruct what happened beneath Galfa.
Based on previous investigations, the event resembles a landslide that occurred at Los Iros following the magnitude 6.8 earthquake north of the Paria Peninsula in 2018.
The working hypothesis is that the area’s geology may have amplified the earthquake’s effects. The Southern Anticline and the area’s mud volcanoes could have made the coastline more susceptible to low-frequency vibrations, triggering a landslide that pushed material seaward and forced the leading edge upwards, creating the uplift now visible along the coast.
Reddock cautioned that the landscape remains unstable.
“The land is still mobile, it’s dynamic, it’s always changing. You could come today and it might be slightly different,” he said, warning visitors to avoid walking on unstable sections upslope where the ground remains disrupted.
In a statement issued on June 29, UWI-SRC director Dr Erouscilla Joseph said there is no evidence that the earthquakes have increased the likelihood of a major earthquake occurring in T&T as a direct result of those events.
“The public should not be alarmed, but they should be prepared,” Joseph said. “Trinidad and Tobago, like Venezuela and many other Caribbean countries, is located within an active seismic region where earthquakes can occur. Events such as this remind us of the importance of preparedness.”
She urged households to review emergency plans, prepare disaster supplies and remember to “Drop, Cover and Hold On” during strong shaking, adding that while earthquakes cannot be prevented, “we can reduce their impacts through preparedness.”
