Earthquake

Article

December 6, 2021

Earthquakes are vibrations or vibrations that occur on the earth's surface due to the sudden release of internal energy that creates seismic waves. Earthquakes are usually caused by the movement of the Earth's crust (Earth's plates). The frequency of a region, refers to the type and size of earthquakes experienced over a period of time. Earthquakes are measured using a seismometer. Moment magnitude is the most common scale on which earthquakes occur worldwide. The Richter scale is a scale reported by the national seismological observatory which is measured on a local magnitude scale of 5 magnitude. Both scales are the same as long as their range of numbers is valid. Earthquakes of magnitude 3 or above are mostly barely noticeable and if magnitude 7 more has the potential to cause serious damage over a large area, depending on the depth of the quake. The largest historic earthquake has been over 9 in magnitude, although there is no limit to its magnitude. The last major earthquake of magnitude 9.0 or greater was a magnitude 9.0 earthquake in Japan in 2011 (as of March 2011), and it was the largest Japanese earthquake since records began. Vibration intensity was measured on a modified Mercalli Scale.

Earthquake type

Types of earthquakes can be distinguished based on:

Based on cause

Tectonic earthquakes These earthquakes are caused by tectonic activity, namely the sudden shift of tectonic plates that have a strength from very small to very large. This earthquake causes a lot of damage or natural disasters on Earth, strong earthquake vibrations can spread to all parts of the Earth. Tectonic earthquakes are caused by the release of energy that occurs due to the shifting of tectonic plates like a rubber band being pulled and released suddenly. Impact earthquakes These earthquakes are caused by the impact of meteors or asteroids that fall to Earth, this type of earthquake is rare Collapse earthquakes These earthquakes usually occur in limestone areas or in mining areas, these earthquakes are rare and local in nature. Artificial earthquakes Artificial earthquakes are earthquakes caused by human activities, such as dynamite, nuclear explosions or hammers hitting the earth's surface. Volcanic earthquakes (volcanoes) These earthquakes occur due to magma activity, which usually occurs before a volcano erupts. If the activity is higher, it will cause an explosion which will also cause an earthquake. The earthquake was only felt around the volcano.

Based on depth

Deep earthquakes Deep earthquakes are earthquakes whose hypocenter is more than 300 km below the earth's surface (in the earth's crust). Deep earthquakes are generally not very dangerous. Medium earthquakes Medium earthquakes are earthquakes whose hypocenter is between 60 km to 300 km below the earth's surface. Medium earthquakes generally cause minor damage and the vibrations are more pronounced. Shallow earthquakes Shallow earthquakes are earthquakes whose hypocenter is less than 60 km from the earth's surface. These earthquakes usually cause great damage.

Based on earthquake waves/vibrations

Primary waves Primary waves (lungituudinal waves) are waves or vibrations that propagate in the earth's body at speeds between 7–14 km/second. These vibrations originate from the hypocenter. Secondary Waves Secondary waves (transverse waves) are waves or vibrations that propagate, such as primary waves, at a reduced speed of 4–7 km/sec. Secondary waves cannot propagate through the liquid layer.

The cause of the earthquake

Most earthquakes are caused by the release of energy produced by the pressure caused by the earth's plates moving in one or more directions. The longer the pressure, the more

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