Explain the characteristics and spatial distribution of the following hazards using at least two specific examples. [10 marks]
Natural hazards are extreme weather that happens in different regions of the world. They bring bad impacts on the environment and the people and different kinds of hazards can cause another one to happen such as earthquakes causing tsunamis. Hazards become disasters when the surroundings are greatly affected. One of the examples of natural hazards is earthquake that occur with only little or no warning.
There is no known way of predicting the magnitude, time and place where the earthquake will happen. From the observations, it can be found that earthquakes happen more frequently as population and infrastructure increases. These increase can lead to change in the ground structure which causes the most severe damages. As the sudden rupture happens, earth will start to shake which is caused by series of waves, called seismic waves. Seismic waves moves from the center of the earthquakes to the outer parts of the earth.There are two types of seismic waves which are body waves and surface waves; body waves move from below earth to the surface and surface waves move only near or on the surface. Surface waves are the ones that fenerate the strongest shaking and damages. Earthquakes can occur in three different depths; shallow one is less then 60km deep and 300km to 700km is categorized as deep focal depth. Since it takes time for the deep to reach the surface, it doesn't really cause harm. Richter scale is used to measure the size of an earthquake which has a scale of 0.1 to 10. When it is less than 3.5, we can hardly feel it nor it is reported. From 4 to 5, the earthquake only affects the buildings that are poorly built. 5 to 6 affects small regions and causes slight damages. 6 to 7 can affect areas within 100km range. 7 to 8 is considered as major earthquakes and it has serious damge. 8 or greater can cause serious damage up to areas that are 100km far.
For earthquakes that happen on land, they mostly happen near the coast rather than in the middle of the landmass. For those that happen in the sea, places where the most distructive earthquakes happen are in the Circum-Pacific belt and Mediterranean-Himalayan belt. Circum-Pacific Belt surrounds the rim of the Pacific ocean and 80 percent of the earthquakes is concentrated in this part. The Mediterranean-Himalayan belt covers from Gibraltar to the East. Shallow focus earthquakes mostly happen in the mid-oceanic ridges.
One of the example of earthquakes that happened was in Chile on May 22 in 1960. This had a miagnitude of 9.5 which can cause serious damge in areas several hundred km across. This is considered as the world's most powerful earthquake in the 20th century. Due to this earthquake, 4,485 people were dead or injured and 2million lost their homes. This earthquake damaged the port of Puerto Saavedra which caused 550 million dollars of damage. The damage of this earthquake expanded to Hawaii, Japan and the Philippines.
Another example is the one that happened in January 2012 a 7.0 magnitude earthquake it Haiti. 230,000 people died and 300,000 people were injured. The earthquake caused 1.5 million people to be displaced and have no home to go to. From this earthquake, many of the famous buildings including Presidential Palace, the National assembly and the main jail were destroyed or greatly damage.
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