Structure and Shape

And Allah says in the Quoran:  "And by the Earth which is cracked (za_tish sadi)"
Surah At-Tariq Surah 86 Ayah 12

The continental plates, which form the surface of the Earth, show  cracks in-between where they meet. These are the so-called continental faults or cracks. They can only be seen clearly where the plates meet, usually at the bottom of the oceans (deep sea vents, see B1/1), and have only been discovered after the Second World War when deep sea research was established. Rarely, there are such cracks visible on the surface of  the Earth:  

http://www.scotese.com/

And Allah says in the Quoran: "Allah is He Who created seven Firmaments and of the earth a similar number. Through the midst of them (all) descends His Command: that ye may know that Allah has power over all things and that Allah comprehends all things in (His) Knowledge." 

Surah At-Talaq Surah 65 Ayah 12

The earth is built up of certain layers, three main layers as defined in modern geography, the crust, the mantle and the core going from the outer to the inner layers. The crust is divided into two separate structures of  rocky material, the mantle into three different regions and the core into two subdivisions (see Compton's Encyclopaedia, "The Earth's Layer's".) These vary in substance and density and consist mainly of magma (liquid rock), iron and nickel. So they are exactly seven, as stated in the Quran in the verse above.  

Geology Atmosphere Seven Layers, Duty and Role 

And Allah says in the Quoran:  "It is He who hath created for you all things that are on earth; moreover His design comprehended the heavens for He gave order and perfection to the seven firmaments; (sab'a sama_wa_t(in)) and of all things he hath perfect knowledge" Surah Al-Baqara Surah 2 Ayah 29.

Two words are used for heaven or sky in the Quran: "asma" and "taraiq". One can be translated as firmament (asma) and the other one as heaven (taraiq). Both have a distinguished scientific meaning and implication. The meaning of heaven (taraiq) will be dealt with in Astronomy 2, the meaning of firmament (asama) is being dealt in this chapter. The seven firmaments are the seven layers of the Earth's atmosphere. According to modern geological definition these are defined as the following: Troposphere, stratosphere, mesosphere, thermosphere, exosphere, ionosphere and magnetosphere (Compton's Encyclopedia), exactly seven in number: 

And Allah says in the Quoran: "So He completed them as seven firmaments (sab'a sama_wa_t(in)) in two Days and He assigned to each heaven its duty and command. And We adorned the lower heaven with lights and (provided it) with guard. Such is the Decree of (Him) the Exalted in Might Full of knowledge" Surah Ha-Mim Surah 41 Ayah 12.

Each of these seven layers has an essential role and duty in the protection of life on Earth. It reflects back hazardous material and electromagnetic waves. For example the ozonosphere reflects back a high percentage of hazardous ultraviolet light (UV), some 98 %. Being a part of the stratosphere, it consists of O3, oxidised oxygen, a state only possible under different conditions up in the stratosphere (40 km above the ocean level). It lets through 2% of the solar UV, the essential amount for life on the surface of the Earth. Through pollution, it is being reduced and the rate of skin-cancer is increasing. There is actually an ozone hole which opens up each spring over the Antarctic and triggers the greenhouse effect and global warming: By the Firmament (sama_wa_t(in)) which returns Surah At-Tariq Surah 86 Ayah 11 The seven layers themselves, being gaseous compounds, are returned to the Earth permanently and are kept back from evaporation by the gravity of the Earth: So the firmament returns itself due to its mass in the gravitational field of the Earth. It also reflects back hazardous material and waves into the universe and other essential substances back to the Earth. Only a small percentage is let through, like the 2% UV from the sun, which is the vehicle of photosynthesis and necessary for us to be able to breathe in the first place. An oath worth swearing as in S 86: A11. Only the very Creator of the Earth can have sworn this oath since it was written down 1350 years ago. Neither did methods for the measurement of atmospheric refraction exist in those times nor were there any satellites for taking infrared pictures of the layers of the atmosphere. Neither were there balloons with thermometers and signal transmission which are a basic necessity for measuring changes in the atmosphere. These were not invented for at least another 1000 years.

http://volcano.und.nodak.edu/vwdocs/vwlessons/plate_tectonics/plate_glance.html

And Allah says in the Quoran:  "He created the heavens and the earth in true (proportions): He makes the Night overlap (yukaw wirul) the Day and the Day overlap the Night:He has subjected the sun and the moon (to His law) each one follows a course for a time appointed. Is not He the Exalted in Power He Who forgives again and again?"

                Surah Az-Zumar 39 Ayah 5  
And Allah says in the Quoran: "And He spread the earth (Walarha bada dza_lika daha_ha_)"

                Surah An-Nazi'at, 79 Ayah 30 

And Allah says in the Quoran: "It is He Who has made the earth manageable for you so traverse ye through its tracts and enjoy of the Sustenance which He furnishes: but unto Him is the Resurrection. Do ye feel secure that He Who is in heaven will not cause you to be swallowed up by the earth when it shakes (as in an earthquake)?"

Surah Al-Mulk 67 Ayah 15/16 

By the description of the relation between night and day and the overlapping exchange of the light in S39: A5 we can clearly see, that the change from night to day and vice versa are movements similar to the coiling or winding of a cloth around a ball shaped object. The word "yukaw wirul" in Arabic stands for the coiling movement of the turban around the head. This must have been written down after oral revelation through the Creator of the earth, because it was in a time without distant sea travelling leave  alone space flight and the predominant theory of the churches stated that the Earth was flat.

The second Ayah (S 79: A30) shows us additionally that this ball shaped earth must have been spread or squeezed, since daha is the Arabic word for an ostrich egg, which is oval shaped. This is completely true, since the rotating centrifugal force of the earth around its axis causes it to spread towards the equator and flattens it at the poles. The diameter at the poles is approximately 43km less than at the equator. This difference keeps varying because of the liquid state of the inner mantle and liquid

Outer core of the Earth. So the Earth has a certain plasticity left from the time of its early stage of being a liquid magma ball over 4 billion years ago (see A 6/1, A5/1).

Finally, the two last verses (S67: A15/16) indicate that the Earth had to be made manageable for mankind. to be able to travel through it and enjoy it fully. This indicates clearly that the hard crust and stable surface of the Earth did not always exist and in the second verse it is immediately mentioned that the Earth could still "swallow" us "up", like it would have done in the early stage when it was unstable and earthquakes were more frequent. Life, leave alone mankind could not exist without this manageability of the Earth commanded to it by the Creator and we are  asked to appreciate it and travel through it and enjoy it as long as we fear him and his punishment. One way of punishing ignorant men is through earthquakes, which can swallow whole cities.