Unformatted text preview: 43. The waves advance in a backward—rotating, elliptical motion. A. S- D. None of these are correct. B. Rayleigh E. Love C. P— 44. At present, the world population of humans is growing at a rate of % per year.
A. 0.12 D. 22 B. 1.2 E. 12 C. 0.02 45. The early differentiation of the Earth into a mantle and a core was created by .
A. the buildup of heat and the melting of iron which was pulled by gravity to the center of the Earth. B. nuclear ﬁssion in the center of the Earth, which converted hydrogen and helium to iron. C. gravitational accretion of iron—rich particles in the core, followed by silicate-rich particles in the mantle. 46. Using the S—P timing method, epicenters can be located using seismograms ﬁom a minimum of
recording stations. A. three C. two
B. four D. one 47. The polarity of the Earth‘s magnetic ﬁeld has A. reversed polarity once during geologic time. B. reversed polarity erratically several times in the last 10 million years. C. remained stable through geologic time. D. reversed polarity several times and at regular time intervals in the last 10 million years. 48. Which statement is not correct based on the correlation between frequency and magnitude of natural
processes A. Rare occurrences are high in magnitude B. Small—scale activity is common C. Frequent occurrences are low in magnitude D. The larger the event, the shorter the return—period 49. The time needed for a typical atom in an oceanic plate to complete a plate-tectonic cycle is A. Material does not recycle via tectonic processes.
B. about a million years C. about a hundred thousand years D. about 10 million years E. in excess of 250 million years ...
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- Spring '08