8:52 PM – Light Felt Earthquake NW of Trinidad

At 8:52 PM Friday 27th March 2020, a minor (preliminary) Magnitude 4.4 (Md or Mt) earthquake struck 92 KM NE of Carúpano, Venezuela, 130 KM NW of Port of Spain, Trinidad and Tobago and 133 KM SW of St. George’s, Grenada.

UWI SRC’s preliminary solution for the light earthquake Friday night.

This event occurred at a (preliminary) shallow depth of 10 Kilometers. This information is preliminary from the U.W.I. Seismic Research Centre, the authority for seismic and volcanological information in the Eastern Caribbean. Quake parameters such as location, depth, and magnitude may change upon review from a seismologist at the SRC.

This event has been reported felt across parts of Northside Tobago; Riseland, Tobago; Mount Pleasent, Tobago; as well as Diego Martin and Westmoorings in Trinidad. It was not reported felt in Grenada. You can submit felt reports to the University of the West Indies Seismic Research Centre.

There is no tsunami threat.

There are four conditions necessary for an earthquake to cause a tsunami:

  1. The earthquake must occur beneath the ocean or cause material to slide in the ocean.
  2. The earthquake must be strong, at least magnitude 6.5.
  3. The earthquake must rupture the Earth’s surface and it must occur at shallow depth – less than 70 KM below the surface of the Earth.
  4. The earthquake must cause vertical movement of the seafloor (up to several meters).

These conditions were not met.

Note that across the globe, different seismic monitoring agencies use different methods, or several methods, for processing quake parameters. Each method has its limitations and will likely produce different results within the ranges of the uncertainty of that data. This is generally accepted within the scientific community.

Based on the location and depth of this earthquake, it is tectonic in origin and occurred on the western border of seismic zone 1, the Paria Peninsula.

Seismic zone one is a complex, and without a doubt, the most seismically active area near Trinidad. Within zone one, the South American plate is beginning to rapidly descend into the Earth’s mantle as the detached oceanic lithosphere exists at depths between 50 to 300 kilometers. (Russo et al. 1993). This zone is one of the most active seismogenic sources in the Eastern Caribbean and has the potential to generate earthquakes up to Magnitude 8.0.

At shallower levels where this quake occurred, the North Coast Fault Zone, as well as the El Pilar Fault, part of the Boconó-San Sebastian-El Pilar Fault system, run across Zone 1. These fault systems compensate for the stress built up as the Caribbean plate slides past the South American plate. Hence, most of these earthquakes from these fault systems are shallow to moderate between 0 to 70 kilometers.

Within 20 kilometers of the epicenter of this earthquake, since 1960, there have been 20 recorded events, generally in two groups – those less than 10 kilometers suggesting shallow faulting and those below 50 kilometers suggesting interaction with the subducting slab.

Based on records going back to the 1960s, if the location of this quake doesn’t drastically change, this will be the strongest quake within the 20-kilometer radius in recent, recorded history. The largest quake that occurred in this area were recorded as magnitude 3.6 (Md) quakes, occurring on February 16th, 1995 and March 26th, 1992.

Earthquakes *cannot* be predicted – meaning the precise time, date, magnitude, depth, etc. cannot be known ahead of time based on current research and technology.

Generally, across the Eastern Caribbean, a seismically active area, earthquakes of this magnitude, up to M8.0 and greater, are possible and this statement has been repeated by seismologists at the U.W.I. Seismic Research Centre for decades.

Each year, over 2,200 seismic events are recorded in the Eastern Caribbean. On average, the Eastern Caribbean has seen a pattern of major (M7.0-M7.9) quakes every 20 to 30 years. That pattern has stayed true. The last major (M7.0-7.9) quake occurred north of Martinique in 2007. 

Historical patterns indicate great quakes (M8.0+) on the Richter Scale have occurred every century or so in the region. The probability of another event at that level is high since the last >M8.0 earthquake occurred in 1843.

Now is the time to create or go over your earthquake preparedness plan and know what to do during, before and after an earthquake. See here for more details.

Facebook Comments