Earthquake

       Made up of  'earth' and 'quake' the term 'earthquake' refers to any tremors abruptly felt on the earth's crust. The tremors range from just noticeable to highly destructive ones. The waves of earthquake are either horizontal, moving side to side or vertical, moving up and down. The underground where the waves of earthquake origin is called hypocenter or focus and the point on the surface where the tremors are most intense is called epicentre. Energy produced by an earthquake may be thousand times grater than an atomic bomb. Powerful earthquakes have been a major cause of massive destruction of life and property. Structures collapse, cracks are formed on the ground and tsunamis emerge leading to the flooding of the coastal plains. Fukushima disaster of Japan caused by the Pacific Ocean tsunami in 2011 is one of the freshest examples.

Alaska in Earthquake

       The waves of earthquakes, technically called seisms, are measured by an instrumental known as seismograph. the common scale of seismic measurement is the Richter Scale developed by the American seismologist Charles Francis Richter. The scale goes from 0-9. The quake that hit the Haitian capital of Port-au-prince in January 2010 and left over 230,000 people dead, was measured 7.3 on the Richter Scale.

Hanshin Awaji Earthquake

         Based on their causes, earthquakes are grouped into three categories: tectonic, volcanic and artificial. Tectonic earthquakes occur when any two of the plates of crust floating on the liquid mantle and sticking together suddenly slip past each other or one puts into another. these earthquakes are concentrated along the two belts: Circum-Pacific Belt or Pacific Ring that coincides with the coastal areas of the pacific Ocean and trans-Continental belt that stretches from the bay of Bangal to the Caribbean Sea through the Arabian and Mediterranean World. Tectonic earthquakes are most common as well as most powerful and devastating.

San Jose Library

      Non tectonic earthquakes are of volcanic origin. They notify the impending volcanic eruptions. In Hawaii for example, there are hundreds of small quakes one day before every volcanic eruption. The third types of earthquakes are induced by human activities such as filling of reservoirs, pumping water deep into the surface, underground detonation of bombs and deep mine works. These two types of quakes are not so destructive.

Hawaii Earthquake

      Though the earthquake-prone zones have been identified, the occurrence is not predictable. Powerful earthquakes may hit Nepal any time in the future. Because of its random construction and congestion, Kathmandu has been presented by several studies as the city to be most devastated by a powerful earthquake. The general public need to be aware of this fact. Structures have to be designed so as to minimize the damages and prevent casualties. At least new houses should be avoided and everyone needs to be trained on how ta act to respond to possible disasters.   

Taiwan School