The Mountains Heights Are Changing Constantly

It kind of feels strange to think that the mountains are either growing taller or shorter. However, it is true. The surface of the Earth is constantly undergoing changes and mountains and mountain ranges have changed to a great extent since they came into existence. To understand this phenomenon we need understand how these mountains came into existence. Well, mountains can form in a few different ways; however the majority of the mountains came into existence due to the movement of the tectonic plates that converged. Tectonic plates are the moving pieces of the lithosphere, the outer layer of the earth. However, we need to keep in mind that not all the plates are alike. The continental plates are fairly light, while the Oceanic plates are denser in nature. So how does the movement of these plates give rise to mountains? Mantle convection is responsible for the movement of the tectonic plates. It is basically caused by the movement of the materials in the mantle due to the heat from the Earth's core. It is almost similar to a pot of curry placed on the hot stove, As the pot or the mantle heats the pieces of curry begins to rise and fall essentially forming a vertical circulation pattern, this is exactly what happens

with the rocks moving through Earth's mantle. when the tectonic plates move and collide the oceanic plates gets pulled under the continental one and this process drives the magma to the continent's surface leading to the creation of volcanic mountain like that of Mount Fuji in Japan. Again when two continental plates collide, the crust at their boundary gets displaced and pushed upwards giving way to formation of a new mountain range.

The Himalayan mountain range and the Tibetan plateau formed as a result of the collision between the Indian Plate and the Eurasian plate that had begun some 50 million years ago and it still continues today. In the year 1856, Mount Everest was measured for the first time by the Great Trigonometrical Survey of India, and they calculated height was measured at 29,002 feet. However, in the last one hundred and fifty years there have been many climbers who have climbed the Everest and many of them conducted surveys and done their own calculations, unfortunately none of those measurements quite match up.

In a new development Nepal is sending its own team up to the Himalayas to conduct several surveys using different surveying methods hoping to arrive at a definitive height. After the 7.8 magnitude earthquake hit the Himalayas in the 2015 it reshaped some part of the mountain range. Satellite reports shows height of the mountain in the Langtang region of the Himalayas had dropped over 3 feet. After the original survey conducted a century ago, an Indian team in 1950's had measured the Everest at 29,029 feet which is still considered as the official height. The Chinese had confirmed this measurement during a survey in the 1970's. However yet another survey by the Chinese in 2005 report said that without the ice and snow on top of Everest the mountain only measured 29,017 feet. While in 1999 Americans using GPS gear had measured it at 29,035 feet.

This also is one of the reasons why Nepal started putting together this mega survey in 2017. This is also an attempt to put to rest the long standing debate regarding the actual height of Mount Everest.

By: Madhuchanda Saxena

Content: https://www.smithsonianmag.com/smart-news/nepalese-expedtion-wants-find-out-if-earthquake-shrunk-mount-everest-180971963/