vibrations induced in the earth's crust due to internal or external causes that virtually shake up a part of the crust and all the structures and living and non living existing on it,defined as earthquake
CAUSES OF EARTHQUAKE
the earthquake can be of non tectonic or tectonic character.among the non tectonic causes,vibrations induced due to volcanic eruptions,atomic explosions and collapse of ground are common.the tectonic earthquakes are the most common and often the most destructive events.these are caused due to displacement of block fractures called faults.
EFFECTS OF EARTHQUAKE
appearance of an earthquake of appreciable magnitude is generally accompanied by a train of effects some of which are highly destructive in nature.the character of the effect varies with the severity of the earthquake as well as distance of the place under consideration from the epicenter of that particular earthquake.RICHTER classifies the effect of earthquake into two main categories:primary effects and secondary effects.
primary effects:-all such effects which are directly related to the cause of origin of earthquake.Origin of new springs and creation of sand dykes are main example of this.
secondary effects:-all those effects which are related to passage of seismic waves and associated shaking motion of the ground during an earthquake are broadly grouped as secondary effects.the effects on standing structures as building,tunnels,towers,dams and reservoirs vary from simple disturbance to complete destruction creating havoc.loss of life and damage to property are two standard measures for describing the effects of an earthquake.