After the shock, the Pacific tenanized. A gigantic earthquake of magnitude 8.8 was activated early this Wednesday, July 30, in front of the Russian Kamchatka Peninsula, causing tsunamis alerts in almost all riverside countries in the Pacific Ocean. This magnitude is the strongest recorded in the region for 73 years: on November 5, 1952, an earthquake of magnitude 9 had caused devastating tsunamis throughout the Pacific Ocean.
Particularly active, this subduction area, where a tectonic plaque is submerged under another, located in the Kamchatka Peninsula, at the east end of Russia, has known several earthquakes in recent years, however less importance. The last one, of a magnitude of 7.4, was recorded on July 20.
“We have in the whole Pacific what is called the Pacific Fire belt, it is the border of the plates between the Pacific Ocean and the surrounding plates,” explains Jean-Paul Montagner, a seismologist of the Physique Du Globe Institut of Paris, to BFMTV.com.
Plates that move 10 cm per year to the “mega earthquake”
“The peaceful plaque is submerged under Kamthatka, since it also dives under Japan, irregularly,” he adds to the specialist, who emphasizes that “the plates move around 10 centimeters per year.”
As Jean-Paul Montagner explains, in the case of the 8.8 earthquake that occurred in the Pacific, as in others studied in recent years, the phenomenon is caused by “an accumulation: the plate advances, but is blocked at the level of the subduction zone”, which causes the surplus of a break “and very violent the dish that begins to the plate to the” “
“These are classic phenomena that give rise to very large earthquakes,” summarizes. More particularly in active subduction zones, such as the one that stays out of Kamchatka.
“This release of the tectonic forces is done with pain and causes large earthquakes,” adds the specialist.
The earthquake that hit the Pacific this Tuesday, or Wednesday, according to the time areas, is considered a “mega earthquake, is not far from the magnitude 9”, which means “that the fault has broken more than several hundred kilometers with trips, so the plate probably collapsed between 10 and 20 meters.”
Earthquakes
In the world, there are several places that could be compared to this Russian subduction area: in Alaska, Mexico, Chile or Indonesia, but also in Antilles or in Europe, especially in southern Greece and Italy.
These earthquakes are “a general phenomenon that is linked to the general dynamics of the Earth, therefore, to the fact that the tectonic of the plates causes movements of the plates on the surface and when two plates come in collision, we have earthquakes that occur regularly, with recurrence times that may vary between 50 years and 1,000 years.”
However, “we cannot predict” these earthquakes in time and space precisely. “We plan that there are earthquakes, but predicting on a scale of a few days, it is still impossible,” explains Jean-Paul Montagner.
According to him, in the face of these phenomena, “the most reasonable attitude is to protect yourself from it, prepare for the occurrence of said earthquake. Therefore, it is necessary to build buildings according to earthquake standards, populations must be prevented.”
Source: BFM TV
