Elastic rebound theory of earthquakes pdf

In geology, the elastic rebound theory is a theory which tries to explain why earthquakes occur. This gradual accumulation and release of stress and strain is now referred to as the elastic rebound theory of earthquakes. Illuminates the causes of earthquakes by elastic rebound theory and earthquake location as focus and epicenter. Duponts plasticslip theory rocks store bending energy until they cannot store it any longer, then snap like a rubber ball. In geology, the elasticrebound theory is an explanation for how energy is released during an earthquake. This activity was developed for use in a high school grades 912 earth science class. Earthquake classroom activities and lesson plans geology. The stored elastic energy has to go somewhere because it has been suddenly released. The elastic rebound theory was developed 100 years ago from the observations of coseismic surface ruptures induced by the 1906 california earthquake. Oblique view of a highly generalized animation of a subduction zone where an oceanic plate is subducting beneath a continental plate. Basically elastic rebound is the primary reason earthquakes even happen. The three types of directional stress experienced by rocks are compressional, tensional, and shear stress fig.

This scenario can happen repeatedly on a 100500 year cycle. Similarly, the crust of the earth can gradually store elastic stress that is released suddenly during an earthquake. In about 75% of earthquakes, the focus is in the top 10 to 15 kilometers 6 to 9 miles of the crust. The epicenter is the point on the land surface that is directly above the focus. The elastic rebound theory was developed by harry fielding reid, an american geophysicist who was studying the 1906 san francisco earthquake. Earthquake causes an earthquake is the shaking of the earththe earth s crust caused by a s crust caused by a release of energy the movement of the earths plates causes most earthquakes. Slippage at the weakest point the focus occurs after buildup of strain. Elastic rebound theory elastic rebound theory over the course of time, one can observe that the two sides of an active fault are in slow but continuous movement relative to one another. Previously it was thought that ruptures of the surface were the result of strong ground shaking.

This is what is known as the elastic rebound theory of tectonic earthquakes. What makes an elastic rebound possible during an earthquake. In geology, the elastic rebound theory was the first theory to satisfactorily explain earthquakes. A brief history of seismology usgs earthquake hazards program. Over time stresses in the earth build up often caused by the slow movements of tectonic plates. This is called the elastic rebound theory, and it explains most but not all movements. Reids elastic rebound theory rocks store elastic energy until they cannot store it any longer, then snap like a rubberband. This theory is known as the elastic rebound theory. 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. In elastic rebound theory, what must occur to produce an earthquake.

However some of the characteristics of earthquakes can be explained by using a simple elastic rebound theory. Reid, university of california publications, bulletin of the department of geology, 6, 19, 1911. This classroom activity would be useful for helping elementary, secondary, middle school, and university students understand this concept. The following animation shows a birds eye view of a country road that cuts through an orchard. At some point the stresses become so great that the. Feb 22, 2014 2 the elastic rebound theory predicts that earthquakes can be generated only in the lithosphere the layer of solid, rigid material. Interestingly, these results are not in agreement with the classical view of the elastic rebound theory reid, 2. The elasticrebound theory of earthquakes bulletin of. Elastic rebound theory as earthearth s plates move past one another, friction s plates move past one another, friction. 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.

Pdf on incorrectness in elastic rebound theory for cause of. When bending rocks fails, the stress energy releases in the form of the earthquake what is one difference between body waves and surface waves. It is only partially correct because it associates earthquakes with geological faults. 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. Reids elastic rebound theory usgs earthquake hazards. Reid, university of california publications, bulletin of the department of geology, 6, 19, 1911 h. Dows recovery theory rocks recover violently when a mass collides with them. Vibrations earthquakes occur as the deformed rock springs back to its original shape. In elastic rebound theory, what must occur to produce an. Multiple choice questions for earthquakes chapter 16. Most earthquakes are the result of the sudden elastic rebound of previously stored energy. Faults occur in rocks of all ages and of all types. While the elastic rebound theory predicts that large earthquakes occur at the. 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.

Reid gave, for example, a crude forecast of the next great earthquake near san francisco. As the earths crust deforms, the rocks which span the opposing sides of a fault are subjected to shear stress. Tectonic movement, whether it is a divergent, convergent, or transform boundary, causes the plates to move and build up stress. This is the principle that reid proposes through his elastic rebound theory of earthquakes. 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. Jan 21, 2016 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. Fixed recurrence and slip models better predict earthquake. Due to the motion of the earths tectonic plates, the ground beneath our feet is always moving, just too slow and g. The mechanisms and processes involved when earthquakes occur are extremely complex. 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. In the theory, fault movements are based on the ability of rock to stick to each other while under stress. Life after death experience nde with steve gardipee, vietnam war story one of the best ndes duration.

Wadati of deep earthquakes located along dipping zones of seismicity where crustal plates subduct into the mantle also helps validate plate tectonic theory. Nov, 2008 video lecture by ross stein of the usgs exerpt from the video, shock waves. How does the elastic rebound theory explain the occurrence of earthquakes. 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. In an earthquake, the initial point where the rocks rupture in the crust is called the focus. Jan 12, 2014 elastic rebound theory elastic rebound theory over the course of time, one can observe that the two sides of an active fault are in slow but continuous movement relative to one another. This is why an earthquake s size is relative to the fault size. Nov 28, 2006 eventually, the strain is too much and the rest of the plate has moved too far and the fault releases the strain buildup all at once in a big stress release called an earthquake. On incorrectness in elastic rebound theory for cause of. An earthquake rupture occurs and relieves some of the stresses but generally not all. Elastic rebound theory rocks at the edges of tectonic plates are subject to tremendous forces resulting in intense deformation. On the other hand, the plate tectonic theory gives the reasons why and how the elastic stress can be built up in crustal fault rocks for cause of earthquakes associated with the elastic rebound theory 5. Starting from a relaxed state at the beginning of a seismic cycle, the rock surrounding the fault accumulates elastic strain.

The theory also predicted, of course, that the place would be along tectonic earthquakes. How do earth scientists explain their contradiction. It is a way for the stored energy to be released through a sudden action. In geology, the elastic rebound theory is an explanation for how energy is released during an earthquake. Elastic rebound theory is directly related to earthquakes. Elastic rebound theory tells us that the elastic strain energy, when not released immediately through creep or other anelastic processes, accumulates over time and this stored energy is available to be released in subsequent earthquakes. What is the elastic rebound theory and how does it relate to. The force per unit area acting on a rock is called stress. Passing right down the middle of the orchard, and across the road, is a fault zone.

However, it is inconsistent and even violates many other phenomena that were present before, during and after earthquakes. How is the elastic rebound theory related to earthquakes. Elastic rebound theory elastic rebound appears to be the primary mechanism of earthquakes. The energy liberated at the time of an earthquake was present there in the form of energy of elastic strain of the rock. A collection of javascript utilities to be incorporated into scientific courseware. Earthquake machineelastic rebound with single block model educational duration. Elastic reboundtheory elasticrebound theelasticreboundtheoryisanexplanationforhow energyisspreadduringearthquakes. The elastic rebound theory of earthquake sources allows rough prediction of the occurrence of large shallow earthquakes. The elasticrebound theory of earthquakes bulletin of the. 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.