Why do earthquakes happen though it is stated in the Quran that mountains were placed into the earth as stakes/piles?

It is stated in the chapters of al-Anbiya, an-Nahl and Luqman in the Quran that mountains prevent earthquakes. However, magnitude 7.6 earthquakes happen in a mountainous place like Pakistan. Despite mountains, earthquakes happen in Muslim countries and Muslims die. If you say it is a test, something like the Quranic verse contradicting Allah will occur. That is, does Allah do the opposite of what is written in the Quran in order to test human beings?

Dear Brother / Sister,

"And We have set on the earth mountains standing firm, lest it should shake with them and We have made therein broad highways (between mountains) for them to pass through…" (al-Anbiya, 21/31)

We, who created them, placed hard pressures on the earth lest it should shake them. That is, we formed hard continents (that is, parts whose backbones are buried in depths) and mountains on the earth in return for water so that the earth would not trouble people and shake people, whom we separated from the sky and gave life from water on it, and so that they would find a place to settle. It is necessary to think that a great trouble would occur if the earth were liquid and people were shaken as the world moved. The earth was made an inhabitable place for people to live with the creation of the mass of land and the placement of the mountains as stakes/piles. We made some areas and roads so that they would find the right path and follow the true route they wish or follow the true path.  

One of the wisdoms behind the fact that earthquakes occur in mountainous regions is to show that earthquakes happen based on Allah’s order, not based on some causes. For instance, some regions are on the fault line but no earthquakes happen there; earthquakes are seen in some regions that are in the second or third degree earthquake zone, not on the fault line.

This shows that earthquakes happen based on Allah's will completely. If Allah orders, mountains shake like cradles.

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