3. Tsunami
A tsunami is a series of water waves caused by the
displacement of a large volume of a body of water,
typically an ocean or a large lake.
Earthquakes, volcanic eruptions and other
underwater explosions (including detonations of
underwater nuclear devices), landslides, glacier
calvings , meteorite impacts and other disturbances
above or below water all have the potential to
generate a tsunami.
4. Earthquake
An Earthquake is a sudden, rapid shaking of the
earth caused by the breaking and shifting of rocks
beneath the earth surface.
The shaking could last seconds or minutes, and there
may be several earthquakes over a period ranging
from hours to weeks called foreshocks and after
shocks, the later decreasing in magnitude with time.
5. flood
A flood is an overflow of an expanse of water that
submerges land. The European Union (EU) Floods
Directive defines a flood as a covering by water of
land not normally covered by water. In the sense of
"flowing water", the word may also be applied to the
inflow of the tide. Flooding may result from the
volume of water within a body of water, such as a
river or lake, which overflows or breaks levees, with
the result that some of the water escapes its usual
boundaries.
6. Forest fire
A forest fire is any uncontrolled fire in combustible
vegetation that occurs in the countryside or a
wilderness area. Other names such as brush fire,
bushfire, wild fire, desert fire, grass fire, hill
fire, peat fire, vegetation fire, and veld fire may
be used to describe the same phenomenon
depending on the type of vegetation being burned. A
wildfire differs from other fires by its extensive size,
the speed at which it can spread out from its original
source, its potential to change direction
unexpectedly, and its ability to jump gaps such as
roads, rivers and fire breaks.
7. Cyclone
In meteorology, a cyclone is an area of closed,
circular fluid motion rotating in the same direction
as the Earth. This is usually characterized by inward
spiraling winds that rotate counter clockwise in the
Northern Hemisphere and clockwise in the Southern
Hemisphere of the Earth. A "tropical cyclone" is a
synonym for a hurricane. Most large-scale cyclonic
circulations are centered on areas of low atmospheric
pressure.