Facts about earthquakes

Earthquakes are short-term vibration of the Earth's crust caused by natural processes and tectonic movements in the lithosphere or artificially(caused by human activity).
Tectonic earthquakes(85%)
-resulting from tectonic movements in the lithosphere due to the sudden release of accumulated energy.Movement of molten mass in the asthenosphere causes the movement of tectonic plates where there is tension in different parts of the lithosphere.When they cross the border tension elastic substances liberated energy causes vibration of different parts of the lithosphere intensity.

Volcanic earthquakes(7%)
-Volcanic earthquakes are the result of the rapid movement of magma toward the surface, and their occurrence is mostly local and regional impacts.(often in very volcanically active areas tremors indicate the movement of magma toward the surface and points to a possible eruption)

Earthquakes collapse(3%)
-resulting from the collapse of cavities or voids in the earth's crust.
Blank spaces usually occur by dissolution of rock that are soluble in water (carbonates, evaporites). Their released energy is much smaller than the tectonic and volcanic earthquakes.Even if they have a limited impact can cause major damage.

Artificial earthquakes are caused by human activity:
-explosion,
-dive, or subsidence due to undermining and digging into the Earth's interior due to mining operations or other geotechnical engineering (mountain stroke),
-discharge of large reservoirs of water,
-pumping oil and water (shrug).

Seismograph-instrument for measuring and recording earthquake,
Seismometer-instrument to detect seismic waves,
Seismograms-records ground vibrations.
An earthquake usually starts with low blows, followed by the main shock,
followed by a weaker shock ..