And mountains are as pegs The Scientific Fact:
In former times, mountains were known as simply rocky blocks protruding from the earth. This definition was considered valid until 1835, when Pierre Bouguer pointed out that the gravitational forces registered in the Andes Mountains are considerably less than what would be expected for such a massive rocky block. Supposedly, for him, a massive block of the same kind must be immersed deep in the earth. It was on this basis that the abnormality of gravity was to be interpreted.
In the middle of the 19th century, George Everest paid great attention to the abnormality of the results of measuring the gravity of the Himalaya Mountains in two different places. Everest, nevertheless, failed to interpret this phenomenon and so he called it The Mystery of India. However, George Airy stated in 1865 that all mountain chains on earth are floating blocks on a sea of magma (i.e. molten rock material beneath the earth’s crust) and that all such molten material is denser than the mountains themselves. As a result, the mountains must dive into this high density material to maintain their uprightness.
Geologists discovered the fact that the earth’s crust is made of adjacent patches called continental plates and that mighty mountains float on a sea of molten material and higher-density rocks below the surface. They also discovered that mountains have roots that help them float and keep fastened to the plates of the earth so it will not shake. In 1948, the Geologist Van Anglin stated in his book Geomorphology (on page no. 27) that it is quite well understood currently that there is a root for each mountain below the crust of the earth.
The function of mountains on the earth is to fasten the crust of the earth. This fact was proven by the principle of hydrostatic balance of the earth as illustrated by the US Geologist Dutton, in 1889. He stated that the protrusions of the earth are immersed into the earth in a way that conforms to their height. Moreover, after the existence of the plates of the earth was proven in 1969, it became clear that the mountains are responsible for maintaining the equilibrium of all the plates.
Facets of Scientific Inimitability:
Man did not know such facts about mountains which have only recently become available in the middle of the 19th century. Meanwhile, the Noble Qur’an in this verse asserts authoritatively that mountains are like pegs in terms of their figure and function. Recently, the accurate simile of this verse proved to be true. The peg has two parts: one on the surface and the other underground and its function is to fasten what is tied thereto. Similarly, a mountain has two parts: one protrudes on the crust of the earth and the other is immersed beneath the ground, in a way that is in conformity with its height. Its function is to fasten the plates of the earth’s crust and prevent them from shaking because of the molten layer beneath. Thus, it becomes evident that the Qur’an is the Word of Allah Who is the Creator of the mountains and all the universe.
Allah, the Almighty, says, {Should not He Who has created know? And He is the Most Kind and Courteous (to His slaves), All-Aware (of everything).} (Al-Mulk: 14)
Source: https://www.islamland.com/eng/articles/mountains-are-pegs-in-form-and-function