Elastic rebound theory rocks at the edges of tectonic plates are subject to tremendous forces resulting in intense deformation. The sudden return of elastically deformed rock to sit original shape is called elastic rebound. Reid s idea was that these distant forces cause a gradual build up of stress in the earth over tens or hundreds or thousands of years, slowly distorting the earth underneath our feet. Elastic rebound theory in plate tectonics was introduced in 1906 by h. With the development of any explanation of a phenomenon comes the ability to predict or forecast future events related to that phenomenon.
Reid gave, for example, a crude forecast of the next great earthquake near san francisco. In geology, the elastic rebound theory was the first theory to satisfactorily explain earthquakes. The force per unit area acting on a rock is called stress. The rocky masses which form the two sides of the fault then snap back into a new position. Reid was one member of an eightperson committee, known as the state earthquake investigation commission. This idea continues to be our main understanding of how earthquakes happen. According to the elastic rebound theory reid, 1910, the seismic cycle consists of two phases. Which one of the following statements concerning foci and epicenters is correct. Banyai geodetic and geophysical research institute of the hungarian academy of sciences, 9401 sopran, po box 5, hungary received march 9, 1990 abstract banyai, l. Assuming that the dislocation front propagates in one direction along the long. What was learned scientifically from 1906 1906 marked the dawn of the scientific revolution reid s elastic rebound theory soil types and damage big quakes can be followed by decades of inactivity paleoseismology 1906 earthquake photos eyewitness accounts other major earthquakes in the sf bay area learn more about earthquakes acknowledgements. The theory also predicted, of course, that the place would be along tectonic earthquakes. Over hundreds to thousands of years, these distant forces cause a gradual build up of elastic energy. The three types of directional stress experienced by rocks are compressional, tensional, and shear stress fig.
The elastic rebound theory was first stated in volume i, part i. The elasticrebound theory of earthquakes bulletin of. Harry fielding reid may 18, 1859 june 18, 1944 was an american geophysicist. Duponts plasticslip theory rocks store bending energy until they cannot store it any longer, then snap like a rubber ball. Reid see box below to explain how energy is released during earthquakes. Reid was professor of applied mechanics at johns hopkins university, baltimore, from 1896 until he became emeritus professor in 1930. The theory involves the slow build up of elastic strain due to largescale stresses in the crust on either side of a locked fault i. What reid developed was an innovative concept he referred to as elastic rebound in rocks as the mechanism for causing earthquakes. How rocks respond to stress is a fundamental concept, critical to forming explanatory models in the geosciences e.
The epicenter is at the surface directly above the focus. In reid s original development of elastic rebound theory, he forecast that the next earthquake should be expected when the surface has been strained through an angle of 12000 reid, 1910. The corollary notion of great earthquakes that punctuate regular strain cycles continues to play a central role in our understanding of earthquake mechanics. Nearly a century after its inception, the elastic rebound model is the canonical macroscopic theory of tectonic earthquakes. Reid, university of california publications, bulletin of the department of geology, 6, 19, 1911. From an examination of the displacement of the ground surface which accompanied the 1906 earthquake, henry fielding reid. The elastic rebound theory in volume ii of the report of the state earthquake investigation commission on the california earthquake of april 18, 1906 andrew lawson, ed. As the earths crust deforms, the rocks which span the.
This view of the origin of earthquakes is supported by the nature of seismic signals which emanate from many earthquakes, and is. This snapping back into position, upon the release of strain, is the elastic rebound of reid s theory the elastic rebound theory is an explanation for how energy is spread during earthquakes. Tectonic movement, whether it is a divergent, convergent, or transform boundary, causes the plates to move and build up stress. This led to the development of the elastic rebound theory, which explains why most. Elastic rebound theory of earthquakes, now generally recog nized as an important advance in the science of geology. Elastic rebound theory has formed the cornerstone of long. Video lecture by ross stein of the usgs exerpt from the video, shock waves. Over time stresses in the earth build up often caused by the slow movements of tectonic plates.
Reid, harry fielding 18491944 an american geophysicist, reid proposed the elastic rebound theory of earthquake motion after studying the 1906 san francisco earthquake. Previously it was thought that ruptures of the surface were the elastic rebound theory. The paper also shows that the energy released during earthquake is not the elastic stress and strain energy accumulated in brittle crustal rock solids during. Reid s theory naturally enough great efforts were made to explain the causes of earthquakes h. Ground displacement and strain evoiution near a fault based,o, n reid s elastic rebound theory. The elastic rebound theory for the cause of earthquakes harry f. He was a vigorous opponent of continental drift theory, describing wegeners work as pseudoscientific. From an examination of the displacement of the ground surface which accompanied the 1906 earthquake, henry fielding reid, professor of geology at johns hopkins university, concluded that the earthquake must have involved an elastic rebound of previously stored elastic. Elastic rebound happens when stress on rock along a fault becomes so grat that the rock breaks or fails.
The gradual accumulation and release of stress and strain is called the elastic rebound theory of earthquakes. Reid formulated the elastic rebound theory as part of his study of the great san francisco earthquake of april 18, 1906. Henry fielding reid, professor of geology at john hopkins university, baltimore developed the elastic rebound theory discussed later from his studies of displacements and strain in the surrounding crust following the. In geology, the elasticrebound theory is an explanation for how energy is released during an earthquake. Elastic reboundtheory elasticrebound theelasticreboundtheoryisanexplanationforhow energyisspreadduringearthquakes. Harry fielding reid, hitchcock lectures henry fielding reid while a member of the state earthquake investigation commission. Similarly, the crust of the earth can gradually store elastic stress that is released suddenly during an earthquake. The first is the interseismic stage, during which elastic strain accumulates slowly with time due to. According to this theory an earthquake is the result of strain release caused by sudden shearing motion along a fault. Consortium of universities for research in earthquake engineering curee 1998 3 1908. In his hitchcock lectures at the university of california in 1911, reid presented the theory in a clear and general form. Rocks are elastic seeing is believing researchgate.
Slowly they deform, until their internal rigidity is exceeded. The diagram below shows how they have distorted the ground. Modern measurements using gps largely support reid s theory as. When the in geology, the elastic rebound theory was the first theory to satisfactorily explain earthquakes. At some point the stresses become so great that the earth breaks. An earthquake rupture occurs and relieves some of the stresses but generally not all. Previously it was thought that ruptures of the surface were the.
This theory is known as the elastic rebound theory. The fracture of the rock, which causes a tectonic earthquake, is the result of elastic strains, greater than the strength of the rock can withstand, produced by relative displacement of neighbouring portions of the earth. The role of the elastic rebound theory in design and. Surface velocities from survey data in the 1908 lawson report, and the earthquake cycle relative motion of rigid plates. On incorrectness in elastic rebound theory for cause of. As the earths crust deforms, the rocks which span the opposing sides of a fault are subjected to shear stress. Dows recovery theory rocks recover violently when a mass collides with them. Harry fielding reid american seismologist britannica. These models also share the characteristic that they treat earthquakes as a. Harry fielding reid, american seismologist and glaciologist who in 1911 developed the elastic rebound theory of earthquake mechanics, still accepted today. Fixed recurrence and slip models better predict earthquake.
The more stress built up the greater the quake magnitude. Elastic stresses build up as rock deforms slowly over time rocks along fault spring back to undeformed state elastic rebound elastic rebound theory of reid 1908 eosc 110 version. The elastic rebound theory of earthquake sources allows rough prediction of the occurrence of large shallow earthquakes. Reid s elastic rebound theory rocks store elastic energy until they cannot store it any longer, then snap like a rubberband. This gradual accumulation and release of stress and strain is now referred to as the elastic rebound theory of earthquakes. A elastic rebound theory b slip on a fault with a uniform stress drop c seismic moment d energy release during an earthquake ii elastic rebound theory h. Rocks at the edges of tectonic plates are subject to tremendous forces resulting in intense deformation. Elastic rebound theory centre for the observation and.
Elastic rebound theory is one of the central ideas to the mechanics of earthquakes and was originally proposed by reid 1910 following the 1906 san francisco earthquake on the san andreas fault. He was notable for his contributions to seismology, particularly his theory of elastic rebound. Why we need a new paradigm of earthquake occurrence. The elastic rebound theory is an explanation for how energy is spread during earthquakes. Most earthquakes are the result of the sudden elastic rebound of previously stored energy. Reids elastic rebound theory usgs earthquake hazards. Well before the plate tectonic theory was introduced, reid suggested that the forces that cause an earthquake are not near the earthquake, but very far away. However, he also points out that this assumes a complete stress drop, that is, release of all accumulated strain, by the 1906. Historic developments in the evolution of earthquake. As rocks on oppo site sides of a fault are subjected to force and shift.
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