What Characterizes P-Wave Arrivals on the Far Side of the Earth

question 37

Multiple Choice

What characterizes P-wave arrivals on the far side of the Earth at epicentral angles beyond 140°?

• A) They are slowed by about 40% due to refraction through the outer core.
• B) The waveforms of their signals are all upside down due to coming out the other side of the Earth.
• C) They are amplified in intensity by the Ni- Fe in the core.
• D) They arrive sooner than expected because of the abrupt increase in velocity at the mantle- core boundary.

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