The elastic rebound theory of earthquake sources allows rough prediction of the occurrence of large shallow earthquakes. The masses of rock undergo elastic strain, slowly flexing and moving in opposite directions. Feb 21, 2012 mr lima explains how stress and strain on rocks along locked fault lines lead to ruptures and elastic rebound that set off the seismic waves that cause earthquakes. About 5% of earthquakes take place within a plate, away from plate boundaries. Elastic rebound theory says that earthquakes are produced when a.
When an earthquake occurs the seismic waves travel through the earth to the seismic station where the information is. Triggering of aftershocks of the japan 2011 earthquake by. His theory of how earthquakes occur as a result of fracture of rocks along a fault is called elastic rebound theory. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext.
In 1906, henry fielding reid, professor of geology at johns hopkins university, concluded that the earthquake must have involved an elastic rebound of previously stored elastic stress. The material for the next two lectures is based on chapter 8 pgs 2516 press and siever 1994. Reids elastic rebound theory usgs earthquake hazard program. When the stress becomes too great then the rocks separate and an earthquake results. However, it is inconsistent and even violates many other phenomena that were present before, during and after earthquakes. Fault zones are often located near major population centers. Elastic reboundtheory elasticrebound theelasticreboundtheoryisanexplanationforhow energyisspreadduringearthquakes. 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. Earthquakes with a very deep focus cannot be explained by the elastic rebound theory. The process which produces a megathrust earthquake would generate a tsunami, not depicted here. Stick slip refers to the fast movement that occurs between two sides of a fault when the two sides of the fault become unstuck. How rocks respond to stress is a fundamental concept, critical to forming explanatory models in the geosciences e. In elastic rebound theory, what must occur to produce an. Earthquakes occur when a critical amount of stress is applied to the crust.
Oblique view of a highly generalized animation of a subduction zone where an oceanic plate is subducting beneath a continental plate. What links here related changes upload file special pages permanent. According to the elastic rebound hypothesis, most earthquakes are produced by the rapid release of energy stored in rock that has been subjected to great forces. The elastic rebound theory of earthquakes bulletin of the department of geology, calif university of california. In geology, the elastic rebound theory is an explanation for how energy is released during an earthquake. Pdf on incorrectness in elastic rebound theory for cause. Reid, university of california publications, bulletin of the department of geology, 6, 19, 1911.
His elastic rebound theory states that earthquakes occur when elastic strain builds up over time. Following this concept, elastic dislocation models e. According to elastic rebound theory, the blocks of rock on opposite side of a fault are forced in opposite directions by stress. Illuminates the causes of earthquakes by elastic rebound theory and earthquake location as focus and epicenter.
A physical basis for earthquakes based on the elastic rebound model. Tectonics are explained by the socalled elastic rebound theory, formulated by the american geologist harry fielding reid after the san andreas fault ruptured in 1906, generating the great san francisco earthquake. Presently, no models of normal fault earthquake cycles exist, and in. From an examination of the displacement of the ground surface which accompanied the 1906 earthquake, henry fielding reid. Like all theories in any branch of physics, theories of the seismic source should be testable i. The theory also predicted, of course, that the place would be along read more. Elastic rebound theory eventually, the strain along the fault exceeds the limit of the rocks at that point to store any additional strain. When the strength of the rock is exceeded, it suddenly breaks, releasing some of its stored energy as seismic waves. Elastic rebound theory says that earthquakes are produced when.
Start this article has been rated as startclass on the projects quality scale. The primary scientific basis for computing longterm earthquake probabilities on a fault has been reids elastic rebound theory reid, 1911, which posits that the likelihood of a large earthquake goes down when and where there has been such an event, and increases. Nov 17, 20 the elastic rebound theory predicts that earthquakes can be generated only in the lithosphere. According to the elastic rebound hypothesis most earthquakes. Jan 12, 2014 this snapping back into position, upon the release of strain, is the elastic rebound of reids theory the elastic rebound theory is an explanation for how energy is spread during earthquakes. Slow accumulation and rapid release of elastic energy. Most earthquakes are the result of the sudden elastic rebound of previously stored energy. Feb 22, 2014 1 the veolcity of s waves decreases as the waves enter the asthenosphere what does this suggest about the asthenosphere compared to the overlying lithosphere. In geology, the elasticrebound theory is an explanation for how energy is released during an earthquake. In the theory, fault movements are based on the ability of rock to stick to each other while under stress. Tectonic movement, whether it is a divergent, convergent, or transform boundary, causes the plates to move and build up stress. Elastic rebound theory time years strength energy elastic stress buildup energy release cumulative slip a c slip a b c a b c time years the earthquake rocks are made of elastic material, and so elastic. The elastic rebound theory is an explanation for how energy is spread during earthquakes.
In geology, the elastic rebound theory is a theory which tries to explain why earthquakes occur. Video lecture by ross stein of the usgs exerpt from the video, shock waves. These intraplate earthquakes are caused by stresses within a plate. Earthquakes mechanics and effects civil engineering. Over the course of geological time, earthquakes, floods, and other natural events have helped to shape the surface of our planet. Ancient cultural explanations of earthquakes were often.
None of the above explain next, go visit or another suitable web site that details recent earthquakes find info on a recent. The stored elastic energy has to go somewhere because it has been suddenly released. This article is within the scope of wikiproject california, a collaborative effort to improve the coverage of the u. Energy built up when plates try to get past each other is released when plates break free. On incorrectness in elastic rebound theory for cause of. In geology, the elastic rebound theory was the first theory to satisfactorily explain earthquakes.
In elastic rebound theory, what must occur to produce an earthquake. Elastic rebound theory is directly related to earthquakes. The gradual accumulation and release of stress and strain is called the elastic rebound theory of earthquakes. The goal of this lesson is for students to learn the concepts of elastic rebound and friction and how these apply to earthquakes and faults. Life after death experience nde with steve gardipee, vietnam war story one of the best ndes duration. Dows recovery theory rocks recover violently when a mass collides with them. The plane defined by the rupture is known as a fault, and the rock layers. An elastic rebound model for normal fault earthquakes wiley. Earthquakes occur when the frictional forces on the fault surfaces are overcome. 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. The elastic rebound theory is now well accepted as the reason for the occurrence of earthquakes. A better understanding of these processes provides an improved ability to anticipate and communicate the unique aspects of earthquake hazards. Earthquakes affect almost every part of the earth and like rain they can be either mild or catastrophic. The plate moves over a spherical surface, creating zones of weakness.
Intraplate earthquakes happen along these zones of weakness. If a seismograph station measures p waves but no s waves from an earthquake what can you conclude about the earthquakes location. Earthquakes are vibrations of the earth caused by the sudden release of energy, usually along a fault. Due to the motion of the earths tectonic plates, the ground beneath our feet is always moving, just too slow and g. The elastic rebound theory predicts that earthquakes can be generated only in the lithosphere. Elastic rebound theory this theory was discovered by making measurements at a number of points across a fault. Elastic rebound theory of earthquakes in the past, earthquakes were believed to occur because the ground would shake in a very strong manner.
How do earth scientists explain this contradiction. After the devastating 1906 san francisco, california earthquake, a fault trace was discovered that could be followed along the ground in a more or less straight line for 270 miles. Request pdf on incorrectness in elastic rebound theory for cause of earthquakes the elastic rebound theory was developed 100 years ago from the observations of coseismic surface ruptures. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Defining an earthquake defining an earthquake an earthquake is a natural occurrence, like rain. None of the above are aspects of the elastic rebound. A range of mechanisms has been proposed for earthquakes, including elastic rebound hypothesis reid. This gradual accumulation and release of stress and strain is now referred to as the elastic rebound theory of earthquakes. Earthquake theory by wanchung hu on 20170511 abstract earthquake is thought to be due to plate tectonic movement. The elastic rebound theory states that pressure builds in rocks on opposite sides of a fault until. The more stress built up the greater the quake magnitude. Reids elastic rebound theory usgs earthquake hazards. Elastic rebound theory pdf file, 4 kb human line to show different waves pdf file, 187 kb slinkies to show different waves pdf file, 818 kb plot that quake pdf file, 80 kb back to curriculum. How is the elastic rebound theory related to earthquakes.
Assignment 4 introduction to geology geol 1010 1 first, watch the sa fault elastic rebound theory video. This activity was developed for use in a high school grades 912 earth science class. The model adopted in this paper assumes that a medium is permeated with a continuum field of defects and that a flow of defects describes an advanced. According to the theory, a tectonic earthquake occurs when strains in rock masses have accumulated to a point where the. Elastic rebound theory jerky motions on faults produce.
It is a way for the stored energy to be released through a sudden action. The 1906 earthquake and a century of progress in understanding. Earthquakes earthquake measurements slides and pdf files. The elastic rebound model explaining seismological data quantitatively is derived by developing the original elastic rebound theory proposed. Slowly they deform, until their internal rigidity is exceeded. Duponts plasticslip theory rocks store bending energy until they cannot store it any longer, then snap like a rubber ball.
If drainage is unable to occur, the tendency to decrease in volume results in an increase in pore pressure. Pdf physical mechanism of major earthquakes by earthquake cases. Elastic rebound and friction lab lesson plan by deborah kane and dave van dusen. As the earths crust deforms, the rocks which span the opposing sides of a fault are subjected to shear stress. San andreas fault, 1906 earthquake, elastic rebound, seismic. However, based on studies in the tonga islands, earthquakes occur within the weak, ductile. Why we need a new paradigm of earthquake occurrence. Previously it was thought that ruptures of the surface were the result of strong ground shaking. Instructional material complementing fema 451, design examples earthquake mechanics 2 21 if a saturated sand is subjected to ground vibrations, it tends to compact and decrease in volume. Earthquakes earthquake measurements slides and pdf files 1. At some point the stresses become so great that the. It is then only intuitive that any additional stress acting on a fault system that approaches failure could trigger. Elastic strain buildup and brittle rupture stage b figure 7.
Elastic rebound theory more grades 912 science on the learning videos channel duration. However, this theory has several fetal defects which fail to lead successful earthquake prediction. Over time stresses in the earth build up often caused by the slow movements of tectonic plates. Which of the following is an aspect of the elastic rebound theory.
Earthquakes, volcanos and how we can minimise their risks. However, based on studies in the tonga islands, earthquakes occur within the weak, ductile asthenosphere. The rocks then snap apart, releasing energy in the form of seismic waves figure 10. It can be done in small groups or as a classroom demonstration, with students recording data. This scenario can happen repeatedly on a 100500 year cycle.
The rock becomes distorted, or bent, but holds its position until the earthquake occurs. The fault then rupturesthat is, it suddenly moves a comparatively large distance in a comparatively short amount of time. Proposing the elastic rebound theory and basis for the. Source mechanisms of earthquakes theory and practice recent, disastrously large and tsunamigenerating earthquakes, from sumatra in 2004 to chile in 2010 and japan in 2011, have underlined the need to better understand the origins, dynamics, and source mechanisms of earthquakes. It is only partially correct because it associates earthquakes with geological faults. Type of faults dip slip faults strike slip faults figure 6.
The mechanisms and processes involved when earthquakes occur are extremely complex. Causes of earthquakes earthquake hazard and emergency management 22 nature of the causative geological processes is of particular relevance. What was learned scientifically from 1906 1906 marked the dawn of the scientific revolution reids 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. At some point the stresses become so great that the earth breaks. The elasticrebound theory of earthquakes bulletin of. Similarly, the crust of the earth can gradually store elastic stress that is released suddenly during an earthquake. When fault stresses rise above a critical threshold for rupture1, the earth slips along the fault and an earthquake results. Reid gave, for example, a crude forecast of the next great earthquake near san francisco. Elastic rebound theory earthquake locations are determined using triangulation from geos 1004 at virginia tech. After the rupture event, stress buildup resumes until the next earthquake occurs. Photos, videos, and podcasts selected lists of earthquake damage, faults, and effects photos, videos, and podcasts. Elastic rebound theory jerky motions on faults produce eqs three fs of earthquakes. Reids elastic rebound theory rocks store elastic energy until they cannot store it any longer, then snap like a rubberband. The elastic rebound theory was developed 100 years ago from the observations of coseismic surface ruptures induced by the 1906 california earthquake.
Elastic rebound theory earthquake locations are determined. According to the elastic rebound theory, rocks can bend elastically up to a point, until they finally break. However, based on studies done in the tonga islands, earthquakes occur within the weak, ductile asthenosphere. Rocks at the edges of tectonic plates are subject to tremendous forces resulting in intense deformation. The material for the next two lectures is based on chapter. Earthquakes occurring along subduction zones cause tsunamis. Basically elastic rebound is the primary reason earthquakes even happen. This is called the elastic rebound theory which explains the recurrence of earthquakes along active faults and is illustrated by the sawtooth shape of the stress vs.
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