EARTH SCIENCE
VOLCANOES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The energy generated at the focus spreads outward in all directions as seismic waves.
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The epicenter is the point where the energy of an earthquake is released along a fault.
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They are caused when rocks are pulled apart by compression and shearing along a fault.
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They occur along faults and are always followed by a volcanic eruption and a tsunami.
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Detailed explanation-1: -The point within the earth along the rupturing geological fault where an earthquake originates is called the focus, or hypocenter. The point on the earth’s surface directly above the focus is called the epicenter. Earthquake waves begin to radiate out from the focus and subsequently form along the fault rupture.
Detailed explanation-2: -Answer and Explanation: The only statement that is true is that the p-waves or primary waves travel faster, and thus arrive sooner than do the s-waves or secondary waves which is choice B.
Detailed explanation-3: -The focus is the place inside Earth’s crust where an earthquake originates. The point on the Earth’s surface directly above the focus is the epicenter. When energy is released at the focus, seismic waves travel outward from that point in all directions.
Detailed explanation-4: -Earthquake energy is in the form of seismic waves. The seismic waves radiate out from a central point, called the focus or hypocenter, like ripples moving outward from a pebble tossed into a lake. The location directly above the hypocenter, on the earth’s surface, is called the epicenter.
Detailed explanation-5: -6. Figure 18.3: When the two blocks on either side of a fault plane suddenly slip, the energy travels outward from the focus as intense vibrations called seismic waves.