Earthquake is an event that results in the generation of seismic waves. These waves are generated due to the rapid release of Earth’s energy that is stored in the crust. But, have you ever wondered what causes an earthquake? We all know that the Earth is in continuous motion.
This motion is due to the moving Earth plates (tectonic plates). Plates move in response to the continuous flow of rocks within the Earth’s surface. These plates move and rub against each other or sink under each other or even go apart from each other.
When the plates try to move apart, the edges are stuck together while the rest of the plate continues to move. The edges and the rocks around the edges undergo a stress. There comes a point when stress becomes so high that the rocks cannot stand anymore bending. The rocks break apart and the plates move along two different side. The pressure of the breaking of rocks is so high that it makes the Earth’s surface vibrate or shake, that is an earthquake is encountered.
California experiences many earthquakes because there are two tectonic plates that meet underneath California.
This is what we have been listening to since childhood, stories of the naturally occurring earthquakes. Did you know earthquakes are also human induced? Human activities like coal mining, oil mining, constructing large dams and buildings, and inserting liquid into wells cause earthquakes.
In 2008, China encountered the world’s 19th lethal earthquake due to the Zipingpu Dam. It caused fluctuation in the default pressure and resulted in an earthquake. Even Australia went through the human induced earthquake. The city of Newcastle is built over a coal mining area. Millions of rocks were moved during the coal mining. The consequence was the greatest earthquake in the Australian history.
There is one more natural cause of earthquakes. Eruption of volcanoes also causes volcanoes but this is the rarest cause. The pressure released from the eruption of lava causes the earthquake but if the pressure is even and constant, no earthquake is experienced.
Video about what causes an earthquake: