9:01 PM – Light Earthquake Strikes South of Dominica

A light earthquake, registering a preliminary magnitude 4.4 (MLv), occurred at 9:01 PM Thursday 11th February 2021, approximately 40.0 km SE of Roseau, Dominica, 51.0 km N of Fort-de-France, Martinique, and 116.0 km N of Castries, Saint Lucia. This quake’s depth was calculated to be an intermediate to deep depth of 127 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 seismologists at the SRC.

Preliminary information from the University of the West Indies Seismic Research Centre concerning the M4.4 earthquake South of Dominica.
Preliminary information from the University of the West Indies Seismic Research Centre concerning the M4.4 earthquake South of Dominica.

The event was not reported felt. 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 quake 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.

Reviewed information from the United States Geological Survey concerning the M4.4 earthquake South of Dominica.
Reviewed information from the United States Geological Survey concerning the M4.4 earthquake South of Dominica.

The United States Geological Survey also recorded this quake at a magnitude 4.4, at a similar location to the UWI SRC’s preliminary report and at a slightly deeper depth.

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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