EARTHQUAKE
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. At the Earth's surface earthquakes manifest themselves by shaking and sometimes displacement of the ground. Earthquakes are mainly caused by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine blasts and nuclear tests. An earthquake's point of initial rupture is called its focus or hypocenter. The epicenter is the point at ground level directly above the hypocenter.
Seismic Zonation map of a country is a guide to the seismic status of a region and its susceptibility to earthquakes. India has been divided into five zones with respect to severity of earthquakes. Of these, zone v is seismically the most active where earthquakes of magnitude 8 or more could occur.
FLOOD
A flood is an overflow of water that submerges land that is usually dry. Flooding may result from the volume of water within a body of water, such as a river or a lake which overflows or breaks levees, with the result that some of the water escapes its usual boundaries or may be due to accumulation of rainwater on saturated ground in an areal flood. Floods can also occur in rivers, when flow exceeds the capacity of the river channel, particularly at the bends or meanders. Floods often cause damage to homes and businesses if they are placed in natural flood plains of rivers. Flood damage can be virtually eliminated by moving away from rivers and other bodies of water.
DROUGHT
A drought is an extended period of months or years when a region notes a deficiency in its water supply. This occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region. Although droughts can persist for several years, even a short intense drought can cause significant damage and harm to the local economy. Drought can also reduce water quality due to less quantity of water to dilute pollutants and increase contamination in the remaining water.
LANDSLIDE
A landslide or landslip is a geological phenomena which includes a wide range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows which can occur in offshore, coastal and onshore environments. Although the action of gravity is the primary driving force for a landslide to occur, there are other contributing factors affecting the original slope stability.
Typically, pre-conditional factors build up specific sub-surface conditions that make the area/slope prone to failure, whereas the actual landslide often requires a trigger before being released.
CYCLONES
In meteorology, a cyclone is an area of closed, circular fluid motion rotating in the same direction as the Earth. This is usually characterised by inward spiraling winds that rotate counterclockwise in the Northern hemisphere and clockwise in the Southern hemisphere of the Earth. Most large-scale cyclonic circulations are centered on areas of low atmospheric pressure.
TSUNAMIS
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, landslides, glacier calvings, meteorite impacts and other disturbances above or below the water all have the potential to generate a tsunami. Tsunami waves do not resemble normal sea waves because their wavelength is much longer. Instead of appearing as a breaking wave, a tsunami may appear instead as a rapidly rising tide, and for this reason they are often referred to as tidal waves. Tsunamis generally consist of a series of waves with periods ranging from minutes to hours arriving in a so-called “wave train”.
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. At the Earth's surface earthquakes manifest themselves by shaking and sometimes displacement of the ground. Earthquakes are mainly caused by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine blasts and nuclear tests. An earthquake's point of initial rupture is called its focus or hypocenter. The epicenter is the point at ground level directly above the hypocenter.
Seismic Zonation map of a country is a guide to the seismic status of a region and its susceptibility to earthquakes. India has been divided into five zones with respect to severity of earthquakes. Of these, zone v is seismically the most active where earthquakes of magnitude 8 or more could occur.
FLOOD
A flood is an overflow of water that submerges land that is usually dry. Flooding may result from the volume of water within a body of water, such as a river or a lake which overflows or breaks levees, with the result that some of the water escapes its usual boundaries or may be due to accumulation of rainwater on saturated ground in an areal flood. Floods can also occur in rivers, when flow exceeds the capacity of the river channel, particularly at the bends or meanders. Floods often cause damage to homes and businesses if they are placed in natural flood plains of rivers. Flood damage can be virtually eliminated by moving away from rivers and other bodies of water.
DROUGHT
A drought is an extended period of months or years when a region notes a deficiency in its water supply. This occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region. Although droughts can persist for several years, even a short intense drought can cause significant damage and harm to the local economy. Drought can also reduce water quality due to less quantity of water to dilute pollutants and increase contamination in the remaining water.
LANDSLIDE
A landslide or landslip is a geological phenomena which includes a wide range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows which can occur in offshore, coastal and onshore environments. Although the action of gravity is the primary driving force for a landslide to occur, there are other contributing factors affecting the original slope stability.
Typically, pre-conditional factors build up specific sub-surface conditions that make the area/slope prone to failure, whereas the actual landslide often requires a trigger before being released.
CYCLONES
In meteorology, a cyclone is an area of closed, circular fluid motion rotating in the same direction as the Earth. This is usually characterised by inward spiraling winds that rotate counterclockwise in the Northern hemisphere and clockwise in the Southern hemisphere of the Earth. Most large-scale cyclonic circulations are centered on areas of low atmospheric pressure.
TSUNAMIS
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, landslides, glacier calvings, meteorite impacts and other disturbances above or below the water all have the potential to generate a tsunami. Tsunami waves do not resemble normal sea waves because their wavelength is much longer. Instead of appearing as a breaking wave, a tsunami may appear instead as a rapidly rising tide, and for this reason they are often referred to as tidal waves. Tsunamis generally consist of a series of waves with periods ranging from minutes to hours arriving in a so-called “wave train”.
