Some parts of the world are earthquake-prone and are often shaken by strong earthquakes.
California, Japan and many other places are located on the fault lines of the earth's crust, and people there are forced to live in constant anticipation of a possible earthquake. There are also places on our planet where, according to scientists, there can be no earthquakes at all. And yet, occasionally they occur where, from the point of view of science, there are no reasons and opportunities for their occurrence.
A series of such earthquakes occurred in the midwestern United States in the 19th century and were strange not only because they happened where they should not have been, but also because these earthquakes were among the most powerful that humanity has encountered.
On the morning of December 16, 1811, there was no sign of trouble in the Mississippi Valley, but at about 2:15 pm the entire region was shaken by the enormous force of tremors, the epicenter of which was in northeast Arkansas. In this region, from the point of view of geology and seismology, there should be no earthquakes, since the earth's crust is stable and there are no dangerous points or stresses that could cause such a phenomenon.
But the earth shaking that happened was, on top of that, incredibly strong. It was estimated at 7.5-7.9 points, caused significant damage and was felt even in New York, Boston, Ohio, Massachusetts and Washington. Then, on the same day, there was a second shock with a force of 7.4 points. Over the next few months, several more earthquakes occurred in the region, all of magnitude 7 to 8, with countless aftershocks.
This continued until March 1812. By this time, the number of concussions was measured in the thousands. The two earthquakes after the first were just as strong. So, on January 23, 1812, an earthquake with a magnitude of 7.8 took place, and on February 7, 1812, tremors reached a strength of 8.8, tore out forests from the ground, formed new waterfalls, islands, geysers, and overturned boats. In the voids formed in the ground, people disappeared. It was then that Lake Reelfoot came into being. Usually these earthquakes were accompanied by a loud rumbling sound, similar to thunder or explosions.
It also noted the appearance of dark clouds in the sky and a strange smelling fog that descended to the ground and made breathing difficult. They talked about the smell of sulfur and strange flashes of light in the sky, which could be the result of a phenomenon called seismoluminescence. Locals said that during the first earthquake and several hours after it, the Mississippi River flowed in the opposite direction. Many saw in this signs of the end of the world, the Indians living in the area spoke of angry spirits.
They remembered that just at that time a comet shone brightly in the sky, which was last seen during the time of Pharaoh Ramses II. Despite the force of the earthquakes, there were very few casualties. This phenomenon remains mysterious to this day. Earthquakes usually occur at the edges of tectonic plates, the nearest of which is very far from the epicenter of the described events. The friction of two tectonic plates is usually the cause of shaking. Other reasons cited were crustal weakening, underground lava flows, an unknown fault, local changes in the mantle, or the release of rock from pressure caused by glaciers.
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One theory indicates that the earthquakes were triggered by a network of underground fissures called the Reelfoot Fault, which formed 700 to 540 million years ago when the ancient supercontinent Rodinia fractured, creating a system of fissures and weakening the crust, setting the stage for earthquakes. albeit somewhat unusual. And this phenomenon has not disappeared. Since 1974, almost 4,000 weak earthquakes have been recorded here.
GUSAKOVA IRINA YURIEVNA