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Outline the Causes of Earthquakes.
Natural Causes
(a) Tectonic movements e.g. movement of tectonic plates. They cause tectonic earthquakes.
(b) Vulcanicity when magma movement displaces rocks suddenly shaking and shuttering them.
(c) Gravitative force when crustal rocks collapse into cauldron due to gravity.
(d) Energy release in the mantle when radioactivity takes place in mantle releasing explosive energy which sends shock waves outwards.
(e) Isostatic adjustment when the continental masses rise to restore the upset state of balance between sial and sima layers.
Human Causes
(a) Exploding nuclear bombs underground which causes shock waves which spread outwards and are felt in the neighborhood.
(b) When a train rolls on its rails causing the ground to vibrate.
(c) Explosion of explosives used in mining and quarrying which cause vibrations to be felt in the neighborhood.
(d) When large reservoirs are constructed and the heavy weight of water reactivate dormant faults causing tremors.
OR
(i) Folding or faulting.
(ii) Isostatic adjustment
(iii) Energy release within the mantle.
(iv) Blasting of rocks or bomb explosions or construction of large reservoirs.
(v) Movement of magma within the earth's crust or volcanic eruption.
maurice.mutuku answered the question on June 5, 2017 at 12:28
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