Light Earthquake Southeast of Antigua. Event Not Reportedly Felt.

At 5:10 PM Thursday 6th February 2020, a preliminary Magnitude 4.3 (Md or Mt) earthquake occurred 91 kilometers northeast of Point-à-Pitre, Guadeloupe and 113 kilometers southeast of Saint John’s, Antigua and Barbuda.

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.

Preliminary information from the University of the West Indies Seismic Research Centre concerning the M4.3 earthquake southeast of Antigua.
Preliminary information from the University of the West Indies Seismic Research Centre concerning the M4.3 earthquake southeast of Antigua.

This event was not reported felt.

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.

Reviewed information from the United States Geological Survey concerning the earthquake southeast of Antigua.
Reviewed information from the United States Geological Survey concerning the earthquake southeast of Antigua.

The United States Geological Survey (USGS) also recorded this quake, at a reviewed Magnitude 4.6 (mb) further south and slightly west of UWI SRC’s reviewed solution. According to the USGS, this quake occurred at a depth of 28.8 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.

Seismicity in this area is very high, with over 230 quakes occurring with 20 kilometers of the epicenter of this quake since 1950. The strongest earthquake occurring within this 20-kilometer area was a magnitude 5.8 on March 10th, 1976 at 16.706°N, 60.758°W at a shallow depth of 15.7 kilometers. Depths of earthquakes in this area are highly variable, as shallow as less than 10 kilometers to as deep as 100 kilometers, within the subducting slab of the North American plate under the Caribbean plate.

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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