After a series of earthquakes, the situation in Puerto Rico remains dire: more than 2,000 people are in shelters, almost 1 million without power and hundreds of thousands without water, writes USA Today.
According to the U.S. Geological survey, from December 31 in Puerto Rico was more than 950 earthquakes and tremors, although many of them were weak and not felt. However, more than 500 had a magnitude of 2 points and above.
The most powerful earthquake of magnitude 6.4 that occurred on the 7th of January, resulted in the death of at least one person, wounding at least nine and a power outage.
So why in the last few days in Puerto Rico have been so many earthquakes?
“The earth of Puerto Rico have suffered from what scientists call a “swarm of earthquakes”. A series of earthquakes, not the usual scheme of the dominant earthquake, accompanied by tremors,” said John Vidale, a seismologist from the University of southern California.
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“We don’t really understand why strong earthquakes continue for some time. It may be associated with slow slip on faults in the area of their actions. Or perhaps, the hydrology of the system faults”, — he added.
According to the U.S. Geological survey, in tectonics of Puerto Rico is dominated by the convergence of tectonic plates of North America and the Caribbean with the island, sandwiched between them.
To the North of Puerto Rico the North American plate beneath the Caribbean plate along the trench of Puerto Rico. (Subduction occurs when an oceanic plate collides with a continental plate and slips under it.)
To the South of the island and South of a strong earthquake measuring 6.4 ball upper crust of the Caribbean plate passes under the Puerto Rico trench, the Muertos.
In Puerto Rico “there is a risk of earthquakes, which is compounded by the fact that its infrastructure is vulnerable, as shown by other recent natural disasters, such as hurricane” Maria-2017 “, — said Vidal.
According to the survey, California fault can cause an earthquake by force of 8 points, moving for the first time. Unfortunately, in Puerto Rico a possible new earthquake and risk of tsunami.
“As always, the chances of additional major events are small, but real. Many regional faults are located offshore, including the subduction zone, so it is also possible tsunamis. However, the establishment of a devastating tsunami need more than a strong earthquake (or called by a landslide)”, — he added.
The USGS said that in the next week with a probability of 3% of the possible aftershocks (one or more) greater than the amplitude of 6.4 points.