Two Light Earthquakes Jolt Parts of Trinidad

On Friday 28th February 2020, two light earthquakes struck northwest to west of Trinidad, causing brief jolts across Northern and Western areas.


(Preliminary) Magnitude 4.8 Earthquake at 10:25 PM

At 10:25 PM Friday 28th February 2020, a preliminary Magnitude 4.8 (Md or Mt) earthquake occurred 113 km west of Port of Spain, Trinidad and Tobago and 131 km northwest of San Fernando, Trinidad and Tobago.

UWI SRC's preliminary solution for the M4.8 earthquake at 10:25 PM Friday 28th February 2020.
UWI SRC’s preliminary solution for the M4.8 earthquake at 10:25 PM Friday 28th February 2020.

This event occurred at a preliminary shallow depth of 10 Kilometers. This information (above) 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 was widely reported felt across Northern Trinidad with parts of Western Trinidad reporting a brief jolt, with an audible rumble.

You can submit felt reports to the University of the West Indies Seismic Research Centre or the United States Geological Survey.

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).

None of these conditions occurred.

FUNVISIS' preliminary solution for the M4.4 earthquake at 10:25 PM Friday 28th February 2020.
FUNVISIS’ preliminary solution for the M4.4 earthquake at 10:25 PM Friday 28th February 2020.

The Venezuelan Foundation for Seismological Research (FUNVISIS) also recorded this quake, at a preliminary Magnitude 4.4 (MW) further south and east of UWI SRC’s preliminary solution. According to FUNVISIS, this quake occurred at a depth of 24.1 kilometers.

USGS' reviewed solution for the M4.6 earthquake at 10:25 PM Friday 28th February 2020.
USGS’ reviewed solution for the M4.6 earthquake at 10:25 PM Friday 28th February 2020.

The United States Geological Survey (USGS) also recorded this quake, at a reviewed Magnitude 4.6 (mb) further south and east of both the UWI SRC and FUNVISIS’ preliminary solutions. According to the USGS, this quake occurred at a much deeper depth of 100 kilometers.


(Preliminary) Magnitude 4.2 Earthquake at 12:55 PM

At 10:55 PM Friday 28th February 2020, a preliminary Magnitude 4.2 (Md or Mt) earthquake occurred 104 km west of Port of Spain, Trinidad and Tobago and 118 km northwest of San Fernando, Trinidad and Tobago. This earthquake was likely a foreshock to the subsequent M4.8 event.

UWI SRC's preliminary solution for the M4.2 earthquake at 12:55 PM Friday 28th February 2020.
UWI SRC’s preliminary solution for the M4.2 earthquake at 12:55 PM Friday 28th February 2020.

This event occurred at a preliminary shallow depth of 10 Kilometers. This information (above) 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 was reported felt across Northern Trinidad with parts of Western Trinidad reporting a brief jolt.

FUNVISIS' preliminary solution for the M4.2 earthquake at 12:55 PM Friday 28th February 2020.
FUNVISIS’ preliminary solution for the M3.8 earthquake at 12:55 PM Friday 28th February 2020.

The Venezuelan Foundation for Seismological Research (FUNVISIS) also recorded this quake, at a preliminary Magnitude 3.8 (MW) further south and east of UWI SRC’s preliminary solution. According to FUNVISIS, this quake occurred at a depth of 28.0 kilometers.

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 these earthquakes, they are tectonic in origin and occurred within seismic zone 1, the Paria Peninsula.

Earthquakes in Zone 1 occur in 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 these quakes occurred according to UWI SRC’s and FUNVISIS’ parameters, 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 the main earthquake, since 1960, there have been over 1300 recorded events, at all depths.

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.

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