Earthquake

Definition

Sudden movement of a block of the Earth’s crust along a geological fault and associated ground shaking (IRDR Glossary).

Earthquake can be defined as the shaking of earth caused by waves moving on and below the earth's surface and causing: surface faulting, tremors vibration, liquefaction, landslides, aftershocks and/or tsunamis (WHO).

 

Facts and figures

The size or magnitude of earthquakes is determined by measuring the amplitude of the seismic waves recorded on a seismograph and the distance of the seismograph from the earthquake. These are put into a formula which converts them to a magnitude, which is a measure of the energy released by the earthquake. For every unit increase in magnitude, there is roughly a thirty-fold increase in the energy released. Earthquake magnitude was traditionally measured on the Richter scale. It is often now calculated from seismic moment, which is proportional to the fault area multiplied by the average displacement on the fault (Australian Government).

There are four different types of earthquakes: tectonic, volcanic, collapse and explosion.

  • A tectonic earthquake is one that occurs when the earth's crust breaks due to geological forces on rocks and adjoining plates that cause physical and chemical changes.
  • A volcanic earthquake is any earthquake that results from tectonic forces which occur in conjunction with volcanic activity.
  • A collapse earthquake are small earthquakes in underground caverns and mines that are caused by seismic waves produced from the explosion of rock on the surface.
  • An explosion earthquake is an earthquake that is the result of the detonation of a nuclear and/or chemical device.

 

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Related content on the Knowledge Portal

  • An 5.3M earthquake in the Pamir mountains of Tajikistan has destroyed hundreds of homes, leaving some 10,000 people without shelter in the dead of winter, officials said (03/01/10).

    Source: www.glidenumber.net

  • Two days of sizable earth tremors were experienced from the evening of 6 December 2009 in the Karonga district in northern Malawi. The tremors, with a magnitude of 5.8 on the Richter scale, caused over eight earth tremors during the first day, affecting approximately 3,000 households and the patients at the Karonga district hospital. Although verification is incomplete, 1,929 affected cases have already been confirmed. Major damage has been triggered by the collapse of walls, rendering houses completely uninhabitable. According to reports received from the Karonga District Assembly, 15 people were injured, nine of whom have been hospitalised. The death of a year-old child, who died of serious injuries after a wall fell on him during the morning of 8 December 2009, has also been reported.

    Soruce www.glidenumber.net

  • An earthquake measuring 5 on the Richter scale shook southwest China's Yunnan Province on Nov. 2. More than 280,000 people were affected, 30,000 homes were damaged and more than 430 heads of livestock killed,according to a statement from the Yunnan Provincial Civil Affairs Department.

    Source: http://www.glidenumber.net/glide/public/search/details.jsp?glide=18953.

  • On 9/30/2009 10:16:11 AM UTC an earthquake of magnitude 7.9 and depth 87km has struck an highly populated area in the Sumatera Barat Province (population: 4.3 million) in Indonesia. GDACS estimates the likelihood for need of international humanitarian intervention to be high (Red alert). It is likely that a tsunami was generated. The maximum tsunami wave height near the coast of Indonesia, Padang will be 3.9m

    Source: http://www.glidenumber.net/glide/public/search/details.jsp?glide=18914&record=2&last=4473

    Source: http://www.gdacs.org/reports.asp?eventType=EQ&ID=66497&system=asgard&location=IDN&alertlevel=Red…

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  • A major earthquake struck Java on 3 September 2009. At least 57 people were killed, hundreds of people were injur d and thousands of houses were destroyed or damaged.

    Source: International Charter

  • A 5.5 magnitude earthquake in Yunnan province (southwestern China) injured more than 300 people and led to the collapse of thousands of homes.

    Source : Glide number

     

    Ressource from OCHA/reliefweb, click here

  • According to Panamenian Civil Protection (SINAPROC), an earthquake measuring a magnitudo of 6.0 hit the country later at night damaging 8 houses and affecting 32 people.

     

    Sources : Glide number

     

    Ressources from OCHA/Reliefweb : click here

  • There have been a series of earthquakes in the area over the past weeks, since May. Approximately 20000 people have been evacuated.

    Source : Charter activation

  • A 5.7 magnitude earthquake hit the Island of Tongoa on 29 May, damaging infrastructure and causing landslides.

    Source : Glide number

  • Government of Belize reported 5 houses destroyed and other damages in infrastructures

    Source : Glide number

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