what is an eartquake?
An eartquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. It is a natural result of the movement of tectonic plates (movement of the groun on opposite sides)
WHAT CAUSES EARTQUAKES ?
Earthquakes are caused by movements of plates underneath the Earth's surface. The places where these plates meet are breaks in the Earth's crust called faults. Earthquakes often happen when these plates along the faults move in different directions.
It happened on 11 March 2011. It was the biggest earhquake until now. It was preceded by a number of large foreshocks ( they are some shakes that occurs before a larger seismic event) and lasted approximately six minutes. The magnitude was 9.0. The earthquake occured at a relatively shallow depth at 20 miles below the surface of the Pacific Ocean. This, combined with the high magnitude, caused a tsunami .
It happened on 17 August 1999 and lasted 45 seconds. It caused 18.373 died people and 48.901 injured people. The magnitude was 6.6
how can we reduce the damages?
It's impossible to prevent eartquakes.Today,new structures in eartquakes sensitive areas are designed to sustain eartquakes without danger of damage or collapse. Buildings can be constructed to withstand eartquakes.