11:30AM Thursday 4th April 2019 Update: UWI SRC’s preliminary solution was added, as well as felt reports for this quake.
At 1:33PM Wednesday 3rd April 2019, a Magnitude 4.2 (MW) earthquake occurred 44.4 KM N of Güiria, Venezuela and 96.9 KM NW of Port of Spain, Trinidad and Tobago. This event occurred at a shallow depth of 25.7 Kilometers. This information was reviewed by an analyst from the Venezuelan Foundation for Seismological Research (FUNVISIS).
The University of the West Indies Seismic Research Centre (UWI SRC) published their preliminary solution at Magnitude 3.3 (Md or mt). The SRC’s preliminary solution also places this quake at a notably deeper depth or 72.21 kilometers, at a slightly further east and north location. This information is preliminary and may vary when additional information is processed by analysts at the SRC.
Note that across the globe, different seismic monitoring agencies use different methods, or several methods, for processing earthquake parameters. Each method has its limitations and will likely produce different results within the ranges of uncertainty of that data. This is generally accepted within the scientific community.
Related: Earthquake Magnitude & Intensity
It was reported felt across parts of Northwestern Trinidad, including Port of Spain, Diego Martin and St. Joseph. You can submit felt reports to the University of the West Indies Seismic Research Centre.
Based on the location of this earthquake, NW of Trinidad, it likely occurred in seismic zone 1. Within zone one, two main mechanisms drive seismic activity.
Firstly, 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. Earthquakes deeper than 50 kilometers are characteristic for this subduction area. If the reviewed solution from UWI SRC maintains the depth, then this quake occurred within the subducting slab of the South American plate.
Secondly, at shallower levels, such as where this earthquake occurred according to FUNVISIS, the North Coast Fault Zone, as well as the El Pilar Fault, part of the Boconó-San Sebastian-El Pilar Fault system, runs 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 between 0 to 50 kilometers.
This area has some of the highest seismicity in the Eastern Caribbean, and this location accounts for the greatest number of earthquakes in the Trinidad and Tobago region. Strong earthquakes in this area have occurred in the past, with the largest being over magnitude 7.0.
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, in Trinidad and Tobago, a seismically active area, earthquakes of this magnitude, up to M8.0 and greater, are possible in area, 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 earthquakes (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.
Related: Earthquake Safety
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.