The short answer is that earthquakes are caused by faulting, a sudden lateral or vertical movement of rock along a rupture (break) surface. 

    Here's the longer answer: The surface of the Earth is in continuous slow motion. This is plate tectonics--the motion of immense rigid plates at the surface of the Earth in response to flow of rock within the Earth. The plates cover the entire surface of the globe. Since they are all moving they rub against each other in some places (like the San Andreas Fault in California), sink beneath each other in others (like the Peru-Chile Trench along the western border of South America), or spread apart from each other (like the Mid-Atlantic Ridge). At such places the motion isn't smooth--the plates are stuck together at the edges but the rest of each plate is continuing to move, so the rocks along the edges are distorted (what we call "strain"). As the motion continues, the strain builds up to the point where the rock cannot withstand any more bending. With a lurch, the rock breaks and the two sides move. An earthquake is the shaking that radiates out from the breaking rock. 

Constant movement of tectonics causes friction and slippage along fault lines that can be found across the globe.

Plate tectonics is the ultimate cause of earthquakes (tensional, strike-slip, compressional).

Earthquakes are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves that make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little. They don't just slide smoothly; the rocks catch on each other. The rocks are still pushing against each other, but not moving. After a while, the rocks break because of all the pressure that's built up. When the rocks break, the earthquake occurs. During the earthquake and afterward, the plates or blocks of rock start moving, and they continue to move until they get stuck again. The spot underground where the rock breaks is called the focus of the earthquake. The place right above the focus (on top of the ground) is called the epicenter of the earthquake.

I agree with Ali Kadhum

The short answer is that earthquakes are caused by faulting, a sudden lateral or vertical movement of rock along a rupture (break) surface. 

    Here's the longer answer: The surface of the Earth is in continuous slow motion. This is plate tectonics--the motion of immense rigid plates at the surface of the Earth in response to flow of rock within the Earth. The plates cover the entire surface of the globe. Since they are all moving they rub against each other in some places (like the San Andreas Fault in California), sink beneath each other in others (like the Peru-Chile Trench along the western border of South America), or spread apart from each other (like the Mid-Atlantic Ridge). At such places the motion isn't smooth--the plates are stuck together at the edges but the rest of each plate is continuing to move, so the rocks along the edges are distorted (what we call "strain"). As the motion continues, the strain builds up to the point where the rock cannot withstand any more bending. With a lurch, the rock breaks and the two sides move. An earthquake is the shaking that radiates out from the breaking rock. 

Dear Neeran, you already got very scientific answers, and I agree with all of them, However, the earthquakes become a regular phenomenon. They scare me a lot.

Regards,

Janusheva

Earthquakes as previously stated are usually caused by the faulting and folding of rock along a fault line where the tectonics plate in response to flow of slow motion of the earth rub against each other. Long Island is built on a fault but the reason there are few major earthquakes is because the small fissures of movement release pressure in small quantities preventing the issues of large tectonic plate movements and increased pressure as seen in San Andréas Faullt. This increased strain on the rock causes it to break and causes a quake, which is the focus of the quake. In my country of France, we rarely have earthquakes because there is little earth movement of the tectonic plate, yet in Italy, there is more movement hence more quakes. The epicenter is the focal point of the quake right above the focus. The plate tectonics causes increased tension. The reason for the increase in earthquakes in recent times has to do with the increase in tension of the plate tectonics brought on by climate change

Dr Réagan

#IStandWithEli

thanks for all answer ...regards

Following

thanks dr. Benjamin

Dear Neeran Jasim,

You have two good points in your explanation:

‘Earthquakes are usually caused when rock underground suddenly breaks along a fault’.

‘he spot underground where the rock breaks is called the focus of the earthquake. The place right above the focus (on top of the ground) is called the epicenter of the earthquake’.

Do you observe the POINT ‘where the rock breaks’ is called hypocentre… If two plate causing the Earthquakes, we have to have hypo-line epy-line of Earthquakes… The plate tectonics also cannot give the response: why does not exist plates onto other rocky planets (Moon, Mars, Mercury and Venus.) The source of moving plates… How we can explain subduction with solid physics?… How begun the plate tectonics? How will stop the plate tectonics onto Earth.? On the Moon also is observing seismic activity: how you can explain it? : On the Moon surface does act ‘plate tectonic theory’

Can somebody tell me Lithosphere why is made from (Crust and superior Mantle)?

Regards,

Laszlo

thanks dear dr.Laszlo...regards

Trivial question.

Any basic book on geology (or, for that matter internet) would give you sufficient information.

I think all of the above answers missing a very unique reason to create earthquake that is meteorite impact on earth.

A single event of earthquake that may shake all of the earth perhaps may be the EARTHQUAKE OF DOOMS-DAY.

REGARDS

Ijaz

Good one, Ijaz.

Some geologists think the dinosaurs disappear because of a big impact!

Cheers,

QJ

Earthquakes can be caused by many reasons, they can be tectonic movements or explosions, or missile launch, etc. However, the most destructive earthquake is caused by tectonic movements caused by activities of magma layers under crust.

From Quraan, linked as https://www.quran411.com/surah-zilzal.asp

بِسْمِ اللَّهِ الرَّحْمَٰنِ الرَّحِيمِ 1. إِذَا زُلْزِلَتِ الْأَرْضُ زِلْزَالَهَا 2. وَأَخْرَجَتِ الْأَرْضُ أَثْقَالَهَا 3. وَقَالَ الْإِنْسَانُ مَا لَهَا 4. يَوْمَئِذٍ تُحَدِّثُ أَخْبَارَهَا 5. بِأَنَّ رَبَّكَ أَوْحَىٰ لَهَا 6. يَوْمَئِذٍ يَصْدُرُ النَّاسُ أَشْتَاتًا لِيُرَوْا أَعْمَالَهُمْ 7. فَمَنْ يَعْمَلْ مِثْقَالَ ذَرَّةٍ خَيْرًا يَرَهُ 8. وَمَنْ يَعْمَلْ مِثْقَالَ ذَرَّةٍ شَرًّا يَرَهُ

Abdullah Yusuf Ali Translation

Dear Masim,

hmm,

You know well that your response is not sufficient: ' Any basic book on geology (or, for that matter internet) would give you sufficient information.'

Why?

See again the question remarks, my before made response, and the best response of Binh Thai Pham. example like Binh Thai Pham’s response you cannot find easy onto internet.

The next:

The dinosaurs did not disappear because by of a big impact!... It seem that this explanation also was gotten:' Any basic book on geology (or, for that matter internet)... '

Take a look to the animals existing in South North America, Central America, South America. Example:

- Blue Iguana (Cyclura lewisi),

- American alligator (Crocodilus mississipiensis);

- American crocodile (Crocodylus acutus);

- Greater rhea (Rhea americana)…

Example this animals rejects the theory propagated by you: the ‘dinosaurs disappeared because of a big impact!’

Regards,

Laszlo

Dear Laslo,

No hard feelings my friend.

The meteorite impact is one of the reasons advocated by some for disappearance of dinosaurs. Others think it may have been due to extensive volcanism, with tremendous outpourings of Deccan lavas at 68-64 Ma as a prime suspect. Yet others have also suggested problems of internal metabolism. Even outgassing has been thought of. It is possible thare was combination of causes. But the disappearance of Dinos was not the end of all sorts of life.

Thanks and regards,

Qasim

thanks for all ... Interesting discussion ...regards

Dear M. Qasim

Thank you for the well-made response.

I have an original explanation to Dinosaurs extensions connected to the: ’ Yet others have also suggested problems of internal metabolism. Even outgassing has been thought of. It is possible thare was combination of causes. But the disappearance of Dinos was not the end of all sorts of life.’ (perhaps in the near future I will write down in a short article)

Regards,

Laszlo

Earthquakes do not threaten the whole world! Most of the world is safe unless you are located near a plate boundary. No relation to climate change whatsoever.

Humans can cause an earthquake by big explosions (nuclear ones are threatened by Mr Kim if he could push his button on his desk), artificial lakes of hydroelectric dams and withdrawing oil and gas deposits without refilling the void created underground.

The collapse of the Twin Towers in NY caused a 2.4 earthquake.

thanks dear dr László and dr. Michael ...greeting

Causes of earthquakes may be natural or anthropogenic which are summarised below:

Natural causes of Earthquakes

· Movement of earth tectonic plates

· Volcanic eruption

· Large meteorite impact

· Large Landslid

· Bubbling and change of axis of the earth

Anthropogenic-Induced Earthquakes

· Nuclear testing/ blast

· Fluid injection into the Earth

· Fluid extraction from the Earth

· Mining or quarrying

· Filling of large reservoirs

Best wishes

thanks dear dr. Indra

Earthquake is the passage of vibrations (seismic wave) that spread out in all directions from the source of the disturbance when rocks are suddenly disturbed. An earthquake is caused by sudden slip on a fault which itself described by epicenter, focus, focal depth, after shock, fore shock, magnitude of earthquake, intensity of an earthquake and intensity. Elastic rebound model is a useful guide to how an earthquake may occur.

The seismic Waves causing a minor earthquake at the World Trade Center was caused by the explosion and imploding of the building after the plane went into the north tower.

Dr Réagan

#ISTANDWITHELI

thanks dear Réagan ..for good information ..

Your welcome Dr Nereen

Dr Réagan

#ISTANDWITHELI

There are 2 very general categories of earthquakes, Natural earthquakes and induced earthquakes the later are caused by explosions, or by the effects of great Dams, mining activities etc.. the first may be caused by either of the 4 causes specified in the slide, most common of them are the tectonic earthquakes. The impact of an exceptionally massive celestial body is the most dangerous although the probability is extremely tiny, however it s a probability and there are more tiny probabilities that happen every day! If you start from your fifth grandpa and grandma, the probability of having you after the all lovely processes during the next generations is certainly very much less compared to the probability of an impact with a massive celestial body! Of course this is valid for all human beings and even more accute for fish ! May I say that the slide is from the following presentation. http://slideplayer.com/slide/6242696/

Important : 1- please notice that slide 16 contains an important error.. the. Number is about 31 fold and not 10 fold , what is 10 fold is the amplitude of the seismic wave not its energy.

2- Earthquakes here are natural eathquakes.

I am not sure if my feelings are supporting by a scientific basis, however I ever wonder about how climate change can affect the whole structure of the planet. Changes in the distribution of water, solid or liquid, produces also changes in the distribution of weights over the tectonic plaques. If ice in the poles melt, the distribution of the water mass changes, and we are talking of millions of tons as it is relatively easy to calculate: an increase in the oceans of 1 cm over 1000 Km2 gives 107 m3 or 1010 tons (I apologize if a commited a mistake in this rapid calculations); the mean argument is that redistribution of the water mass in the entire planet is producing an important pressure on the tectonic plaques that can be the cause of the earthquakes.