Reid's Theory
" Naturally enough great efforts were made to explain the causes of earthquakes" ( H.F. Reid, Hitchcock Lectures)
"Since the material composing the Earth's crust is elastic, and cannot rupture until it is strained beyond its strength, it is evident that an earlier relative displacement of regions on opposite sides of the fault had set up an elastic strain in the intermediate zone, which exceeded the strength of the rock, causing the rupture along the fault to surface.." (Harry Fielding Reid, Hitchcock Lectures) |
While a member of the State Earthquake Investigation Commission, Harry Fielding Reid of Johns Hopkins University examined the ground displacement from the 1906 earthquake. He concluded that earthquake must have involved an elastic rebound of stored elastic stress. This led to the development of the Elastic Rebound Theory, which explains why most earthquakes occur(Byerly and Lawson 2). While some geological organizations say that the theory is too simplistic("The Theory of Elastic Rebound") , most still accept the theory as valid. The U.S. Geological Survey calls the theory the "basis for our modern understanding of earthquakes."