Wednesday 8 January 2020

A mega-swarm of Biblical proportion: Yesterday's mag 6.5 in Puerto Rico was only 1 of 4,000 quakes in the area since January 2019 and almost 1,000 since Dec 28th

Map USGS

According to USGS, more than 4,000 small to mid-sized quakes, including yesterday's magnitude 6.5 have rattled the tiny island of Purto Rico since January the 1st 2019.

The swarm is in the area where a devastating magnitude 7.0 struck Haiti in 2010 killing more than 150,000 people along with the total destruction of 250,000 buildings and 30,000 commercial buildings. The nation's history of the national debt, prejudicial trade policies by other countries, and foreign intervention into national affairs contributed to the existing poverty and poor housing conditions that increased the death toll after the disaster. Wikipedia

Should we expect another big one?

Extensive diversity and complexity of tectonic regimes characterize the perimeter of the Caribbean plate, involving no fewer than four major plates (North America, South America, Nazca, and Cocos).

Since 1900, the two largest earthquakes to occur in this region were August 4, 1946, M8.0 Samana earthquake in northeastern Hispaniola and the July 29, 1943, M7.6 Mona Passage earthquake, both of which were shallow thrust fault earthquakes. A significant portion of the motion between the North America plate and the Caribbean plate in this region is accommodated by a series of left-lateral strike-slip faults that bisect the island of Hispaniola, notably the Septentrional Fault in the north and the Enriquillo-Plantain Garden Fault in the south. Activity adjacent to the Enriquillo-Plantain Garden Fault system is best documented by the devastating January 12, 2010, M 7.0 Haiti strike-slip earthquake, its associated aftershocks and a comparable earthquake in 1770.

More than a hundred aftershocks have been recorded by USGS along the Southcoast of Puerto Rico since yesterday's powerfull mag 6.5 quake, see map below.

Map USGS

 The aftershocks, including two M 5.6's and a 5.0 are part of a mega- swarm which started on the 28th of December and has registered nearly a 1,000 quakes, see map below.

Map USGS

Major Quakes 2020

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