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magnitude – n. the size of something; the strength of an earthquake's power
interact – v. act in such a way as to have an effect on something or someone else
source – n. a person, place or thing from which something comes
crust – n. hard, outer surface of something
exciting – adj. producing strong feelings
continental shelf – n. an area at the bottom of the sea near the coast of a continent, where the sea is not very deep
phenomenon – n. someone or something that is popular, especially because of an unusual ability or quality
track – v. to follow the progress of something
