UNIVERSE
PLANETARY INTERIORS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Deep sea drilling has shown the evolution of basins by core drilling of ocean sediments and oceanic crust.
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The composition of lava extruded from volcanoes has given insight into the composition of the core.
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The development of SONAR mapping has given a clear picture of the depth of earth’s layers.
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Seismic waves will bend and reflect at the interfaces between the layers of the earth.
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Detailed explanation-1: -Seismic waves from an earthquake’s focus travel through the earth along bent paths and are eventually recorded by distant seismograph stations. The character of the waves and the time it takes for them to reach a particular location reveals important clues as to the nature of the earth’s interior.
Detailed explanation-2: -surface waves (in geology) A type of seismic wave that moves only along Earth’s surface, not through the planet’s deeper layers.
Detailed explanation-3: -Seismic refraction. The direction of travel of a seismic wave, like that of a beam of light, can be bent, or refracted, when it passes into or out of different mediums. This seismic refraction occurs only if the mediums have different densities or strengths, which change the velocity of the seismic wave (Figure 1).
Detailed explanation-4: -Seismic velocities depend on the material properties such as composition, mineral phase and packing structure, temperature, and pressure of the media through which seismic waves pass. Seismic waves travel more quickly through denser materials and therefore generally travel more quickly with depth.