A natural disaster is an adverse event caused by natural processes of the Earth. Examples are earthquakes, floods, volcanic eruptions etc. Some disasters are rapid and abrupt while others are slow and continuous. A natural disaster should be defined on the basis of its human consequences and not on the phenomenon that caused it. For example, an earthquake is simply an event in nature. Even a very strong one is not a disaster unless it causes injury or destroys property. Thus, an earthquake occurring in an uninhabited area is not considered a disaster.
A hurricane is a large rotating storm with winds exceeding 74 miles per hour that produces heavy rain falls. They are the most violent storms on Earth. They are called by different names depending on the region of occurrence. They are called hurricanes in North America and Caribbean, Typhoons in Southeast Asia and Cyclones in Indian Ocean. The scientific name for hurricane is tropical cyclone.
The Earth is surrounded by constantly moving air weighing approximately 5 quadrillion tons i.
e. 5,000,000,000,000,000 tons. They form over the warm ocean water of tropics. When warm moist air over the water rises, the cool air rushes in to replace it. This air is also heated and moistened and starts to rise. This cycle leads to formation of storm (rain) clouds and form an area of low pressure. These clouds start to rotate due to rotation of earth. As the cycle continues, the speed of air increases which leads to formation of hurricane.
Hurricanes are categorized into 5 categories depending on the speed of winds. Hurricanes rotate clockwise in southern hemisphere and anti-clockwise in northern hemisphere. They are named based on a list of names maintained by the World Meteorological Organization.
Hurricane Harvey originated from a westward- moving tropical wave over the Atlantic Ocean. It made landfalls in Barbados and St. Vincent before entering the Caribbean Sea. It degenerated into tropical wave and later regenerated into a tropical cyclone. It was a Category 4 hurricane that made landfall on Texas and Louisiana in August 2017. It was the second most costly tropical cyclone causing a heavy damage of $125 billion USD. Hurricane Katrina holds the first position and caused around $160 billion USD damage.
It caused heavy rainfalls, flash and river flooding. The storm dumped more than 27 trillion gallons of rain over Texas breaking all the records and making it the wettest Atlantic hurricane ever measured. It dumped 51 inches of rain in some parts of Texas.
In Texas only, around 300,00 structures and 500,000 vehicles were damaged. It took 107 lives. More than 300,000 people were left without electricity and a large number of people required rescue. In port Aransas, nearly every structure was damaged. About, 20 percent of Rockport’s Population was displaced nearly for a year. The city of Houston was sunk temporarily by two centimeters according to California Geophysicist. 8 million cubic yards of garbage resulted from the floods in Houston alone.
The number of deaths is less due to the successful predicting and planning for hurricanes. The warning was issued about six hours before Harvey formed. In different part of America, different organizations like Coast Guard, Customs and Border Protection etc. worked with FEMA to prepare for Harvey and its aftermath. Many warnings were issued beforehand that helped people to get to safe places.
The earth is made up of three layers: crust(outermost), mantle (middle, semi-solid hot rocky) and core (innermost and hot). The earth’s outer shell is divided into several plates called tectonic plates which lies over the mantle. The tectonic plates are always moving slowly, but because of friction they get trapped at their tops. When the pressure increases and the plate becomes free, an earthquake occurs releasing energy in the form of waves that moves through the surface and induces the shaking we experience. The intensity of earthquake is measured using the Richter scale. The Richter scale is an open scale, but the most powerful earthquake ever recorded was Valdivia earthquake (1960) having magnitude of 9.4-9.6. Earthquakes can also cause volcanic eruptions, tsunamis and landslides.
On 12 January 2010, at 4:53 p.m. local time, a magnitude 7.0 struck Haiti, a country that had been suffering for decades from poor political, economic and social conditions. Haiti is the poorest country in the Western hemisphere. The epicenter was located approximately 25 km (15 miles) south west of Port-au-Prince, the capital city of Haiti. Within the first two hours, eight aftershocks were recorded having magnitude between 4.3 and 5.9. At least 52 aftershocks having a magnitude of 4 or greater were recorded by 24 January. The earthquake was also felt in several surrounding countries like Cuba, Jamaica, Puerto Rica, Venezuela and Dominican Republic. It originated due to contractional deformation along the Léogâne fault.
An estimated three million people were affected by it. Over one million people were initially displaced. Many hospitals were rendered unusable, people were forced to wait days for treatment. The streets were filled with corpses as the morgues were already full. Due to lack of proper documentation as a result of rush in disposing the dead, the death tolls vary from 220,000 to 300,000. Further deaths occurred as serious injuries went untreated as a lack of medical supplies and staff. Around 30,000 commercial buildings collapsed or were damaged severely. The total damage was estimated to be between $7.8 billion to $8.5 billion USD.
Many countries sent their help in form of funds, military personnel, food and medical supplies. Many NGO’s and UN worked together in rescuing and helping people. Over the coming years, many international agencies allocated billions for the people of Haiti.
Japan has faced many natural disasters like tsunami and earthquake over the years. It was struck again with an earthquake on March 11,2011. It was the strongest earthquake ever recorded in Japan. The earthquake originated underwater about 130km (81miles) east of Sendai. It was caused by the rupture of a stretch of the subduction zones which separate the Eurasian Plate from the Pacific Plate. It was preceded by several foreshocks and later was followed by hundreds of foreshocks. The earthquake caused a massive tsunami.
The tsunami waves were about 40 meters high. The tsunami tore apart coastal towns, villages. It destroyed most of the structures in its way. According to some reports, some wave reached 10 km (6 miles) inland. As a result of tsunami, more than 450,000 people became homeless and more than 15,500 people died. The tsunami swept about five million tons debris offshore according to Japanese Government.
The tsunami also damaged nuclear plants. A nuclear emergency was declared at Fukushima Daiichi nuclear power plant. The government ordered evacuation within 10-20 kms of the plant. The nuclear plant fire was brought under control after few days. Material damage from the earthquake and tsunami is estimated to be about $300 billion USD.
According to Japan’s foreign minister 28 international organizations and 116 countries offered their help. Japanese Red Cross reported $1 billion in donations. To sum up, natural disasters cannot be stopped but the damage from these events can be declined. The government should spread awareness and should make the disaster management training mandatory. New rules and regulations should be implemented for safely constructing buildings and infrastructures. Underground bunkers or infrastructure should be developed for people to evacuate during natural disasters. More trees should be planted in flood prone areas. Better prevention and warning system should be installed in oceans and sensitive areas. The sensitive areas should be better monitored. It is said that prevention is better than cure and against the natural disaster prevention is our best weapon.