A book entitled "Earth" is considered a basic reference text in many universities around the world. One of the authors of this book is Frank Press. He is currently the President of the Academy of Sciences in the USA. Previously, he was the science adviser to former USA President Jimmy Carter. His book says that mountains have underlying roots. These roots are deeply embedded in the ground, thus, mountains have a shape like a peg (see figures 7, 8, and 9)..
Figure 7: Mountains have deep roots
under the surface of the ground. (Earth, Press and Siever, p. 413.)
Figure 8: Schematic section. The
mountains, like pegs, have deep roots embedded in the ground. (Anatomy
of the Earth, Cailleux, p. 220.) (Click on the image to enlarge
it.)
Figure 9: Another illustration shows
how the mountains are peg-like in shape, due to their deep roots. (Earth
Science, Tarbuck and Lutgens, p. 158.) (Click on the image to
enlarge it.)
This is how the Quran described mountains. God said in the Quran:
“Have We not made the earth as a bed, and the mountains as pegs?” [Noble Quran 78:6-7]
Modern earth sciences have proven that mountains have deep roots under the surface of the ground and that these roots can reach several times their elevations above the surface of the ground. So the suitable word to describe mountains on the basis of this information is the word 'peg', since most of a properly set peg is hidden under the surface of the ground.
The history of science tells us that the theory of mountains having deep roots was introduced only in the latter half of the nineteenth century. Mountains also play an important role in stabilizing the crust of the earth. They hinder the shaking of the earth. God said in the Quran:
"And He has set firm mountains in the earth so that it would not shake with you.."[Noble Quran 16:15]
Likewise the modern theory of plate tectonics holds that mountains work as stabilizers for the earth. This knowledge about the role of mountains as stabilizers for the earth has just begun to be understood in the framework of plate tectonics since the late 1960's.
