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Reid, Harry Fielding

theory strain crust proposed

(1859–1944) US geophysicist: proposed elastic rebound theory of earthquakes.

Reid has been claimed to be the first American geophysicist. His mother was the great-niece of George Washington, and his prosperous parents took Reid as a child to Switzerland. There began his love for mountains and glaciers. He graduated from Johns Hopkins University in 1876 in physics and mathematics, and returned there in 1894 to teach until his retirement. His major work was his ‘elastic rebound’ theory of the source of the earthquake waves. The theory proposed that strain developed in the Earth’s crust due to forces acting from below, of unknown origin. The strain leads eventually to breaks (faults) in the crust. The sudden release of strain energy by faulting, when the fracture strength is exceeded, can lead to an offset across the fault of up to 15 m. The rupture travels as a wave at about 3.5 km s –1 , for a distance up to 1000 km. The theory was soon accepted (about 1911) in the USA, but more slowly (up to 50 years later) elsewhere.

Reid, Tim (1944–) [next] [back] Reid, Daphne Maxwell (1948–)

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