3 things include a earthquake, a volcano eruption or a earthquake and tsunami. Hope this helps.
<span>True, however 50% is rather optimistic value, it's probobally more. The main source of water is in the ground and the groundwater gets constantly more contaminated with road salt, oil, gasoline and other chemicals (and as you can see, these are all manmade products).</span>
The most resent one i would say floods!! because they have nearly dubbled since 1900!!
