Faults in the earth's crust caused by the earthquake in Nepal in 1255, prompted the scientists that its territory is reset point tectonic "couple" resulting from the collision of the Eurasian and Indian plates, according to an article published in the journal Nature Geoscience.
The southern part of Eurasia is composed of two large tectonic plates — the Eurasian and Indian. Eastern and northern boundaries between them are the entire length of the Himalayas and other mountain massifs, where the clash between the plates causes the rare but extremely powerful earthquake. Often these disasters, such as the earthquake in Kathmandu in 1255, leads to serious destruction and death.
Group of geologists led by Laurent Bolin (Laurent Bollinger) of the Commissariat of Atomic Energy in France Arpajon tried to find fault point Himalayan crust after earthquakes by studying photographs of the river valleys in Nepal.
The authors found some interesting deformations in the valley Sir, flowing down the slopes of the Shivalik mountain range in the south of Nepal. In terms of tectonics, the Shivalik is the lowest and the young slope of the Himalayas, through which the so-called main central thrust — the line of contact between layers of the Indian and Eurasian plates.
Bolin and his colleagues noticed that most of the violations in the structure of the crust occurred recently. Scientists have studied the structure, and were surprised to find that they are not just a strain, and full crustal faults. This fact interested in the authors, and they made an expedition to Nepal to determine the age and nature of these faults.
Field work confirmed that the crust shifts, the picture really are faults. Geologists have calculated their age using radiocarbon dating of organic deposits in the soil "shifted" sections of river valleys. According to their calculations, the faults in the valley Sir emerged around 1255, during an earthquake in Kathmandu.
As they note, this cataclysm led to unusually severe damage and a large number of deaths. According to various estimates, the earthquake in 1255 killed one third of residents of Kathmandu valley, including the King of Nepal Abhaya Malla.
Continuing research valley, archaeologists discovered traces of the fault of another powerful disaster — earthquake in Nepal and the Indian state of Bihar in 1934.
Bolin and colleagues point out that both of their opening rather unusual from the point of view of modern seismology and geology. Previously it was thought that all the powerful Himalayan quake ended dumping tectonic "couple" in the form of fractures, which partly explains the high frequency of such disasters in the region.
Believed geologists, in Nepal, there are several similar faults arising after other earthquakes. This suggests that Nepal is a point of relief tectonic "couple" accumulated in the collision of Indian and Eurasian plates.