Mains Daily Question
March 15, 2024
Q.1 Bring out various direct and indirect evidence that assist in understanding the nature of the Earth’s interior structure.(10M, 150W)
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Approach to the Answer: Understanding and structuring the answer: The question has two main headings: 1) direct source of information about Earth’s interior and 2) indirect source of information. Introduction: Type 1: Write a brief introduction regarding the interior of the Earth or Type 2: Start with writing the significance of understanding the interior of the earth. Body: Heading 1: Write about direct sources of information related to the interior of earth. Heading 2: Mention indirect sources of information for earth’s interior. Conclusion: Type 1: Conclude by writing the importance of these discoveries or Type 2: You can also mention any recent deep drilling or mining news/report. |
Answer: The structure of the Earth's interior is basically the result of enormous and complex processes taking place inside the Earth. The origin of many phenomena like earthquakes, volcanoes, tsunami etc. are linked with the structure of earth’s interior. There are two primary sources of information about the internal composition of the Earth: direct evidence and indirect evidence.
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Direct sources of information about the interior of earth: |
- Deep earth mining: In mining activity, minerals are extracted from deep below the surface.
- For example, gold mines in South Africa are as deep as 3 - 4 km. This gives a direct clue on changing density and composition of rock inside earth.
- Volcanic eruption: Volcanoes deliver information by the means of molten magma that comes out of Earth’s interiors.
- For example, volcanic eruptions in Hawaii island and mid-ocean ridges provide valuable insight into the chemical structure and temporal evolution of Earth's interior.
- Deep ocean drilling: Deep Ocean drilling project reveals vast information through analysis of materials collected at different depth.
- For example, the deepest drill in the Arctic Ocean (Kola) provides information about temperature maps for the Earth's interior, discovery of biological activity in the rocks, Conrad discontinuity etc.
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Indirect sources of information about earth’s interior: |
- Temperature and pressure patterns: An increase in temperature and pressure with depth means an increase in density as well. Hence it becomes possible to determine the rate of change of characteristics of material on earth.
- Meteors: They have material and structure like earth and give information about the materials of which earth is formed of.
- Gravitational force(g): The gravitational force(g) is greater near the poles and less at the equator. Gravitational anomalies give us information about the distribution of mass of the material in the crust of the earth.
- Seismic activity: Earthquakes generate different types of waves (Primary and secondary waves) which suggest properties of different layers of the earth.
Human life is largely influenced by the physiography of the earth. Therefore, it is necessary that one gets acquainted with the forces that influence landscape development. To understand why the earth shakes or how a tsunami wave is generated, it is necessary that we know certain details of the interior of the earth.
