The bottom of North America plate tectonics is

This is the reason why the Southeastern United States, though not on the tectonic plate boundaries (like Japan), still suffers from several earthquakes in recent times.

Almost every natural earthquake occurs at the boundary lines of tectonic plates on Earth's lithosphere. When these tectonic plates move and collide, energy is released and generates an earthquake. Therefore, in countries with a " lying " area in a tectonic plate, earthquakes also rarely occur.

However, in the southeastern United States , where it seems that earthquakes rarely occur, it has been frequently hit by many earthquakes recently. In particular, the most notable is the magnitude 5.8 earthquake that happened in 2011 that shook Washington DC

Cut image of the Earth.

To find out the cause of these strange earthquakes, Berk Biryol, a seismologist at UNC Chapel Hill, and colleagues created a 3D image of the top part of the earth's crust, in other words CT scan of North American plate tectonics.

The image shows that the tectonic plate in the southeastern United States has a thin, uneven surface, there are places where there is a thick concentration of rock and some places are the opposite. The reason for this situation is because more and more soil and rock are added to the surface of tectonic plates. At the same time, tectonic plates move apart to create an uneven thickness.

Large areas of gravity will be strongly pulled by gravity into the core of the earth. And the bottom of this area will be "flaky", mixed into the soft part.

This phenomenon will make the tectonic plates become thinner, easily slipping along the fault line causing the earthquake.

The seismologist learned Berk Biryol estimated that the "peeling" bottom layer of this tectonic plate occurred continuously for about 65 million years, or more.

However, in the near future there will not be many big changes, because geological changes often take place slowly over a very long time, up to millions of years. Therefore, the people of the Southeast United States can still live with peace of mind, at least to the grandchildren's life.