This type of devastation happened on March 11 2011 in Japan when a very powerful tsunami ruined the land, and on October 17 1989 when California was hit by huge earthquake named Loma Prieta. This essay will compare and contrast these two world shaking events and give some research about the two events as well. Maybe you will learn about some interesting facts about the two. A earthquake is described as a sudden and violent shaking of the ground, resulting from the movement within the earth’s crust or from volcanic action. It sometimes causes great destruction.
The movement of the plates is divided in three ways: they move together (converge), the move apart (diverge), or they move past each other [About.com – Geology]. “Earthquakes occur along faults, where huge blocks of rock are grinding past each other. Tectonic motions produce directional pressure, which causes rocks on either side of a large fracture to move past each other. The movement is rarely smooth; usually the blocks stick because of friction, which slows their movement. Eventually, the friction is overcome and the blocks slip abruptly, releasing pent-up energy with a huge “snap”—an earthquake” (The Plate Tectonic Model – Page 107).
This poses a great earthquake hazard to Haiti. But, the disaster was initially caused when the Caribbean plate had a transform with the North American plate. The North and South American plate were moving in a westward direction, while the Caribbean plate was unable to move. This meant that the North American plate had to slide across the Caribbean plate, forcing tension to be built up, and ultimately releasing all the energy in the form of an earthquake. Because Haiti is located almost right on top of the plate boundary near the fault lines where the shock of the earthquake occurred, it took the full force of the magnitude 7.0 earthquake.
The break in tension causes a jerk and the sea floor to spring upwards. This causes the continental plate to spring upwards creating an earthquake. When the sea floor springs upwards the displaced water travels in opposite directions away from the earthquakes epicenter across the ocean. In deep water the waves travel fast and are
The difference in pace and movement of plates, triggers the up build friction. When this friction is released- Earthquakes are generated. An example of an event is the San Francisco earthquake in 1989 on October 17 measuring 6.9 on the Richter scale. Tsunamis are one result of earthquakes. A sudden shift in
Recently, more people have died as a result of inland flooding than any other hazard associated with hurricanes or tropical storms. Rainfall exceeding 15 inches can be expected during hurricanes and tropical storms. Flooding is the leading cause of damage to homes in the United States. Flooding associated with hurricanes and tropical storms can be felt for hundreds of miles inland. 2) How do storm surges increase the likelihood of coastal flooding during a hurricane?
When plates move past, towards or away from each other the movement is not smooth. Friction causes the plates to be stuck. This causes pressure to build up. Earthquakes occur when this build-up of pressure is released. The point where the earthquake starts is called the focus.
Since the degree of impact an earthquake has is measure on both the Richter and the Mercalli scale, it must be reasonable to assume that the power of an eruption is representative to the degree of how potentially hazardous the event may be. Eruption explosiveness can be measured by the Volcanic Explosivity Index. The higher the Volcanic Explosivity Index, the greater the potential hazard. The eruption type is a huge factor in the differences in the degree of hazards posed by volcanoes around the world. This greatly relates to the plate margin the volcano or volcanic belt is situated upon.
Explain the distribution of the worlds major geophysical hazards Some parts of our planet are more often and more severely afflicted by natural hazards than others. This is due firstly to the geological structure of the Earth and secondly due to climate zones. Earthquakes like the Kashmir, Haiti and New Zealand occur in areas where oceanic plates and continental plates move against each other and collide. The long arc of islands that make up Japan and the stretch of the Andes located inside the coast of Chile are collision zones and therefore more often affected by earthquakes than in Finland, Brazil or Canada. Haiti is on the boundary of the Caribbean and North American plates and is an example of a conservative plate boundary.
The epicentre was a town named Leogane; about 19km (12 miles) west of Port-au-Prince, thousands were left homeless and up to 80-90% of buildings in Leogane were destroyed. The quake was quickly followed by two strong aftershocks of 5.9 and 5.5 magnitudes. It was the worst earthquake to hit the Caribbean island in 2 centuries. The island lies on the Enriquilla-Plantain Garden Fault however it was caused by an interaction between the North American and Caribbean Plates. After which the barely noticed island became the centre of the world’s news channels, it became one of the most noticed natural disasters in history with celebrities and normal people alike doing allsorts to raise money and aid for the victims of the quake.