11:10 PM – Minor Earthquake Strikes Southwest of Trinidad

At 11:10 PM Wednesday 25th March 2020, a minor (reviewed) Magnitude 3.6 (Md or Mt) earthquake struck 56.29 KM SSE of Güiria, Venezuela, 70.39 KM WSW of San Fernando, Trinidad and Tobago and 85.51 KM SW of Port of Spain, Trinidad and Tobago.

UWI SRC's reviewed solution for the minor earthquake Wednesday night.
UWI SRC’s reviewed solution for the minor earthquake Wednesday night.

This event occurred at an intermediate depth of 89.27 Kilometers. This information has been reviewed by the U.W.I. Seismic Research Centre, the authority for seismic and volcanological information in the Eastern Caribbean.

This event has been reported felt across parts of Southwestern Trinidad, including Cedros, Moruga and Santa Flora. 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.

FUNVISIS preliminary solution for the 4.1 Earthquake at 11:10 PM Wednesday 25th March 2020.
FUNVISIS preliminary solution for the 4.1 Earthquake at 11:10 PM Wednesday 25th March 2020.

At 11:10 PM Wednesday 25th March 2020, a light preliminary Magnitude 4.1 (Mw) earthquake occurred 63.92 kilometers south-southeast of Güiria, Venezuela and 76.16 kilometers west-southwest of San Fernando, Trinidad and Tobago.

This event occurred at a preliminary intermediate depth of 108.3 Kilometers. This information (above) is preliminary from the Venezuelan Foundation for Seismological Research.

Based on the location and depth of this earthquake, it is tectonic in origin and occurred on the border of seismic zone 3 and seismic zone 5, the Gulf of Paria and south of Trinidad

Within the Gulf of Paria, it is a very faulted, seismically complex area surrounding Trinidad. At this zone, the extension of the Los Bajos fault from southwestern Trinidad, and the Warm Springs Fault from Central Trinidad meets the El Pilar fault. This complex network of faults also includes small, conjugate or perpendicular faults.

High levels of seismic activity occur in this zone, with both shallow and moderate depth earthquakes, generally remaining less than 50 kilometers depth. The UWI SRC has stated during a Q&A of the earthquake swarm between January and February 2018, this location is capable of generating a magnitude 6.5 or greater earthquake.

South of Trinidad, This zone is fairly seismically quiet with regards to earthquakes larger than magnitude 3.8. Russo et al. (1993) defined this zone as a passive margin edge in the Foreland basin in North of South America continent, covering events with strike-slip and mixed thrust and thrust, around the Orinoco-Delta region in Venezuela with an average depth of 50 kilometers and a maximum magnitude of 6.5. Generally, we see episodic moderate (M5.0-M5.9) earthquakes.

Within 20 kilometers of the epicenter of the main earthquake, since 1960, there have been over 78 recorded events, at all depths. The largest quake that occurred in this area was a magnitude 6.5 (Md) quake on February 5th, 1944 and more recently on January 26th, 2018 with a magnitude 5.4 (Md).

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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