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Explain fully how earthquakes occur - Leaving Cert Geography - Question Question 1 - 2008
Question Question 1
Explain fully how earthquakes occur. In your answer refer to a named example which you have studied.
Worked Solution & Example Answer:Explain fully how earthquakes occur - Leaving Cert Geography - Question Question 1 - 2008
Step 1
Explain how earthquakes occur
Answer
Earthquakes are geological phenomena caused by the sudden release of energy in the Earth's lithosphere that creates seismic waves. This release of energy typically occurs along faults, which are fractures in the Earth's crust where blocks of rock have moved past each other. The process can be explained as follows:
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Tectonic Plates: Earth's surface is divided into tectonic plates that float on the semi-fluid asthenosphere below. These plates are constantly moving due to convection currents in the mantle.
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Stress Accumulation: As plates move, they interact at their boundaries, creating stress. Stress builds up when the rocks along a fault are stuck due to friction.
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Elastic Limit: The rocks can deform elastically up to a certain point. Once the stress exceeds this elastic limit, the rocks will break or slip, resulting in an earthquake.
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Energy Release: The sudden release of energy causes seismic waves to propagate outward from the focus (the point within the Earth where the earthquake originates), leading to shaking at the surface.
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Types of Earthquakes: There are various types of earthquakes, including tectonic earthquakes (caused by the movement of tectonic plates), volcanic earthquakes (associated with volcanic activity), and induced earthquakes (resulting from human activities like mining or reservoir-induced seismicity).
Step 2
Refer to a named example
Answer
One named example of an earthquake is the 2011 Tōhoku earthquake in Japan, which occurred on March 11, 2011. This was a powerful undersea megathrust earthquake that registered a magnitude of 9.0.
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Location and Cause: The earthquake occurred at the boundary of the Pacific Plate and the North American Plate, where stress had been building for centuries. The release of this stress led to the sudden plate movement.
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Impact: The earthquake triggered massive tsunamis, causing widespread destruction and leading to the Fukushima Daiichi nuclear disaster. Over 18,000 people were either killed or reported missing as a result of the disaster.
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Aftermath: This earthquake highlighted the importance of earthquake preparedness and the need for improved disaster management strategies in seismic-prone regions.