According to the elastic rebound theory reids, 2 the seismic cycle consists of two phases. The location below the earths surface where the earthquake starts is called the hypocenter, and the. In the past, earthquakes were believed to occur because the ground would shake in a very strong manner. According to the elastic rebound theory, rocks can bend elastically up to a point, until they finally break. How do earth scientists explain this contradiction. The mechanisms and processes involved when earthquakes occur are extremely complex. Elastic reboundtheory elasticrebound theelasticreboundtheoryisanexplanationforhow energyisspreadduringearthquakes. The elastic rebound theory is an explanation for how energy is spread during earthquakes. If drainage is unable to occur, the tendency to decrease in volume results in an increase in pore pressure. The elastic rebound theory of earthquake sources allows rough prediction of the occurrence of large shallow earthquakes. Basically elastic rebound is the primary reason earthquakes even happen. According to the elastic rebound theory reids, 2 the seismic cycle consists of two. When fault stresses rise above a critical threshold for rupture1, the earth slips along the fault and an earthquake results.
The movement of earths crust resulting from the release of built up potential energy between two stuck tectonic plates. Ch 6 quiz multiple choice chapter 6 multiple choice 1. Types of earthquakes and faults most earthquakes in the world occur along the boundaries of the tectonic plates as described above and are called interplate earthquakes e. Jan 24, 2012 a theory of small earthquakes teaches us something new about love and sex, jealousy and loyalty, and, most importantly, motherhood. Earthquakes that occur within plate boundaries, called intraplate earthquakes, have long intrigued. In elastic rebound theory, what must occur to produce an earthquake. Triggering of aftershocks of the japan 2011 earthquake by. 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. 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. Slowly they deform, until their internal rigidity is exceeded.
Earthquakes most often occur along existing faults whenever the frictional forces on the fault surfaces are overcome. Over time stresses in the earth build up often caused by the slow movements of tectonic plates. The theory also predicted, of course, that the place would be along tectonic earthquakes. The surface where they slip is called the fault or fault plane. Earthquakes occur when a critical amount of stress is applied to the crust. This release of energy causes intense ground shaking in the area near the source of the earthquake and sends waves of elastic energy, called seismic waves, throughout the earth. Ayelet waldman, author of bad mother and red hook road in her ten previous nonfiction books, meredith maran has trained her journalistic eye on the subtle dance between the political and the personal. Reids elastic rebound theory rocks store elastic energy until they cannot store it any longer, then snap like a rubberband. On the morning of april 18, 1906, san francisco was struck by a violent earthquake that shook the city and ignited an even deadlier menace a threeday fire that burned up and down the citys streets and incinerated its buildings and neighborhoods.
Sometimes seismological data are not based directly on seismograms. Illuminates the causes of earthquakes by elastic rebound theory and earthquake location as focus and epicenter. It is then only intuitive that any additional stress acting on a fault system that approaches failure could trigger. Pdf physical mechanism of major earthquakes by earthquake cases. Duponts plasticslip theory rocks store bending energy until they cannot store it any longer, then snap like a rubber ball. As rocks on oppo site sides of a fault are subjected to force and shift. A number of earthquakes also occur within the plate itself but away from the plate boundaries e. 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.
In the standard rebound theory of earthquakes, elastic deformation energy is. Due to the motion of the earths tectonic plates, the ground beneath our feet is always moving, just too slow and g. 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 stress. For example, they may be subjective assessments of damage following an event. 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. An earthquake is what happens when two blocks of the earth suddenly slip past one another. In geology, the elastic rebound theory was the first theory to satisfactorily explain earthquakes. Though it is releasing the energy equivalent of a 7. The elasticrebound theory of earthquakes harry fielding. The rocks then snap apart, releasing energy in the form of seismic waves figure 10. 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. Earthquakes earthquakes occur when energy stored in elastically strained rocks is suddenly released.
Mar 09, 2016 this video discusses the relationship between plate boundaries and earthquakes, deformation, elastic limit and rebound and the 3 kinds of faults earthquakes can happen in. The plane defined by the rupture is known as a fault, and the rock layers. Dows recovery theory rocks recover violently when a mass collides with them. New zealands geologic hazards agency reported this week an ongoing, silent earthquake that began in january is still going strong. 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. The destructive force of earthquakes has stimulated human inquiry since ancient times, yet the scientific. New explanation for slow earthquakes on san andreas. Pdf understanding the physical mechanism of major earthquakes is very important for earthquake prediction. How is the elastic rebound theory related to earthquakes. The elastic rebound theory for the origin of earthquakes was first proposed. 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. 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.
Elastic rebound theory moment magnitude scale earthquakes. Elastic rebound theory is directly related to earthquakes. In geology, the elasticrebound theory is an explanation for how energy is released during an earthquake. Nov 17, 20 the elastic rebound theory predicts that earthquakes can be generated only in the lithosphere. Seismic waves free download as powerpoint presentation.
Vibrations earthquakes occur as the deformed rock springs back to its original shape elastic rebound. According to the elastic rebound hypothesis most earthquakes. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Rocks at the edges of tectonic plates are subject to tremendous forces resulting in intense deformation. This book presents an innovative new approach to studying source mechanisms of earthquakes, combining theory and observation in a unified methodology, with a key focus on the mechanics governing. Previously it was thought that ruptures of the surface were the result of strong ground shaking.
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. Obviously, the fault deformation in the elastic rebound hypothesis is. As the earths crust deforms, the rocks which span the opposing sides of a fault are subjected to shear stress. Transfer due to slip on the fault, and is defined as. However, based on studies in the tonga islands, earthquakes occur within the weak, ductile.
Ppt elastic rebound theory powerpoint presentation free to download id. At some point the stresses become so great that the. Reids elastic rebound theory not only allowed to explain the. This activity was developed for use in a high school grades 912 earth science class. Ppt elastic rebound theory powerpoint presentation. The rise of earthquake science living on an active earth.
Elastic rebound theory says that earthquakes are produced when a. Elastic rebound earthquake mechanism slippage at the weakest point the focus occurs. D chandrasekharam department of earth sciences head, centre of studies in resources engineering indian institute of technology bombay such news items raises several questions like what are earthquakes. Several wellknown premonitory effects such as anomalous variation in the ratio of longitudinal v p and shear v s seismic velocities,v p v s, tilt, regional and local. A theory of tectonics in which the outer part of the earth lithosphere is comprised of rigid plates that interact collide, translate, rift apart, subduct. Reids elastic rebound theory usgs earthquake hazard program. The scale independent inclusion theory of rock failure developed in part i is applied to the problem of crustal earthquakes and, in particular, to the problem of premonitory phenomena reported to precede such earthquakes. However, based on studies done in the tonga islands, earthquakes occur within the weak, ductile asthenosphere. Reid, the elasticrebound theory of earthquakes, univ. Life after death experience nde with steve gardipee, vietnam war story one of the best ndes duration. This video discusses the relationship between plate boundaries and earthquakes, deformation, elastic limit and rebound and the 3 kinds of faults earthquakes can happen in. The elastic rebound theory is now well accepted as the reason for the occurrence of earthquakes.
Reids elastic rebound theory usgs earthquake hazards. 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. In elastic rebound theory, what must occur to produce an. When the strength of the rock is exceeded, it suddenly breaks, releasing some of its stored energy as seismic waves. The science behind earthquakes what is an earthquake. The term refers to how the earth is built of plates, and the theory. 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. The gradual accumulation and release of stress and strain is called the elastic rebound theory of earthquakes. Learning earthquake tip 1 earthquake design and construction. In geology, the elastic rebound theory is an explanation for how energy is released during an earthquake.535 595 827 637 18 1297 1048 1268 531 1340 1094 1303 1206 1316 512 1245 519 449 538 548 1314 1220 1416 1271 1335 42 845 1007 594 825 335 916 564 1254 788 799 310 1404 1129 1022 434