11:33 AM – Light Earthquake Felt Across Trinidad

At 11:33 AM Monday 17th August 2020, a reviewed Magnitude 4.5 (Md or Mt) earthquake occurred 44 km NW of Port of Spain, Trinidad and Tobago,
66 km NW of Arima, Trinidad and Tobago, and 85 km NW of San Fernando, Trinidad and Tobago

This event occurred at a depth of 35 Kilometers. This information (above) is preliminary by the U.W.I. Seismic Research Centre, the authority for seismic and volcanological information in the Eastern Caribbean.

This event has NOT been reviewed by an analyst. It was automatically located by a seismological computational system, therefore, it is a PRELIMINARY result and this may vary when new additional data are processed.

Reviewed information from the University of the West Indies Seismic Research Centre concerning the M4.5 Earthquake west of Trinidad.

This event was widely reported felt across Northern Trinidad, Northeastern Venezuela, and southwestern 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).

None of these conditions occurred.

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.

Seismicity in this area is very common, with 108 quakes occurring with 10 kilometers of the epicenter of this quake since 1960. The strongest event occurring within this 10-kilometer area a magnitude 5.2 earthquake on September 13th, 1979. Most quakes in this area register below magnitude 5.0, making this quake the second (preliminary) strongest quake within a 10 km.

This quake likely occurred in seismic zone 4, north of Trinidad.

Earthquakes in Zone 4 can be associated with the subducting slab of the South American Plate, resulting in a deeper event of depths between 40-55 KM, but it can be deeper. Quakes in this area can also be associated with the North Coast Fault System, which runs just offshore the Northern Coast of Trinidad, where events are usually less than 40 KM depth. This area typically produces light (M4.0-4.9) or moderate (M5.0-5.9) magnitude earthquakes. Earthquakes in this zone tend to produce less aftershocks than earthquakes elsewhere across Trinidad and Tobago.

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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