Prepare learn what you can do to prepare for an earthquake before, during, and after. Earthquakes have shaken british columbia since the time of indian legend. The energy input occurs at a near constant rate, and is a result of slow continuous deformation. An earthquake occurs when earth shakes because of the release of seismic energy following the rapid movement of large blocks of the crust along a fault. Earth shakes movement in narrow zones along plate boundaries is the cause of most earthquakes. Most earthquakes, but not all, occur in the boundary regions between tectonic plates. An earthquake is what happens when two blocks of the earth suddenly slip past one another. Leftslip and rightslip faults are types of strikeslip faults. Lateral spreading is the sideways movement of liquefied soils on gentle slopes. Earthquakes 5 earthquake characteristics an earthquake is a trembling of the ground that results from the sudden shifting of rock beneath the earths crust. Earthquakes may cause liquefaction, landslides, fire, and tsunami which would lead to far higher level of damage and losses. Earthquakes in canada i in canada, most earthquakes are small. Earthquake resilience guide for water and wastewater utilities. According to one theory, rocks get hot enough at the break to form a slippery layer of glassy rock along the fault.
Earthquake preparedness checklist unlike other natural disasters, earthquakes cannot be predicted, and occur without warning. Estimating casualties for large earthquakes worldwide. Introduce the story on master 2, the turtle tale, and read it aloud. When an earthquake occurs in a populated area, it may cause deaths and injuries and extensive property damage. The heat melts the plate, which can spew back up as. Earthquakes earthquake measurements slides and pdf files 1. Myanmar earthquake committee 2018 when an earthquake occurs, its magnitude can be given a single numerical value on the richter magnitude scale ml.
Mapping the natural hazards faced by nepal 21 boxes definitions 9 box 1. The great shakeout earthquake drills are an opportunity to practice how to be safer during earthquakes. Introduction to earthquake engineering notes ebook free. An earthquake is caused by a sudden slip on a fault. The surface where they slip is called the fault or fault plane. Before an earthquake during an earthquake after an earthquake for more information on earthquake. Defining an earthquakeunit i, level 1, grades k2 i 2. When an earthquake occurs, the following actions shall be taken inside buildings and classrooms. Intraplate earthquakes occur in the interior of plates, away from the plate margins. From 19002000, only about 20 earthquakes caused significant damage in canada. Preparing your family for an earthquake ucla health. Staff shall have students perform the drop procedure. Geologists study earthquakes to understand where they are likely to happen and how people can be prepared and protected when an earthquake strikes. Terms in this set 31 how do particles move in the ground when an earthquake occurs.
The energy earthquakes release travels in the form of waves called seismic waves. Using wooden blocks, construct a building with four walls. Risk, detection, warning, and research congressional research service 3 figure 1 also shows relatively high earthquake hazard in the rocky mountain region, portions of the eastern seaboardparticularly south carolinaand a part of the central united states known. Measuring earthquakes california academy of sciences. Depending on the local tectonics, deformation ranges between. Is325 earthquake basics emergency management institute. The point on earths surface directly above the focus is called the epicenter ep i sent uhr, as shown in figure 2. Locating the epicenter of an earthquake notes this is a seismograph taken from a seismometer. An earthquake is a shock wave that radiates to the earths surface from underground. Ground movement during an earthquake is seldom the direct cause of death or injury. Estimating casualties for large earthquakes worldwide using an empirical approach. However, the intensity is variable over the area affected by the earthquake, with high intensities near the epicentre the point where the earthquake occurs and lower values further away. Usgs and ceri scientists estimate that there is a 2540% chance of a magnitude 6. Additional general information can be found on the.
Understanding your septic system type, location, and components before an earthquake occurs will make this guide more useful. The pacific coast is the most earthquakeprone region, followed by eastern canada. When the strength of rock is exceeded, movement occurs along the fault and energy is released, causing an earthquake c. Ground shaking, what we call an earthquake, occurs when strain energy is released in a rupture somewhere in the lithosphere, i. Map of tien shan with gps velocities relative to eurasia figure 4. In the following lab, you will see how construction materials can be used to help strengthen a building. Anywhere in california, an earthquake could happen, and i would not be extremely surprised, hellweg said. Earthquakes occur over much of the world and the united states. There are approximately 4000 earthquakes recorded here per year. Most are smaller than the initial earthquake but larger magnitude aftershocks also occur.
Line students up single file in a long corridor indoors. Can cause major damage to poorly constructed buildings over small regions. Locate the shutoff valves for water, gas and electricity. A large part of the bay area is at risk for liquefaction. Faults can be identified by the offset of rock layers on either side of the fault surface. Earthquake science and hazard in central asia 5 list of tables, figures and boxes figures figure 1. This module is focused on assessing only earthquake shaking hazard and risk. Uw emergency management website on and fema website. Most earthquakerelated injuries result from collapsing walls, flying glass, and falling objects as a result of the. And, after the earthquake is over, the process of strain buildup at this modified interface between the rocks starts all over again figure 6. Most seismic activity occurs at three types of plate boundaries. Another kind of fault, a convergent fault, occurs where plates push against each other. The sudden slip at the fault causes the earthquake a violent shaking of the earth when large elastic strain energy released spreads out through seismic waves that travel through the body and along the surface of the earth.
The movement of earths crust resulting from the release of built up potential energy between two stuck tectonic plates. The report is intended to help students and others visualize what causes earthquake shaking and some of the possible results of the shaking. Shakeout also has been organized to encourage you, your community, your school, or your organization to update emergency plans and supplies, and to secure your space in order to prevent damage and injuries. Stick simulation of earthquakes fault action game map scales to measure distances vocabulary development of. The rupture occurs on planes of weakness comprising crushed and broken rock that geologists refer to as faults fig. Severe earthquakes destroy power and telephone lines, gas, sewer, or water mains, which, in turn, may set off fires. Stress occurs at plate boundaries when the plates separate, collide, subduct, or slide past each other seisomogram a tracing of earthquake motion that is recorded by a seismograph. During, and after an earthquake this resource provides guidance for septic system users before, during, and after an earthquake. In the example above, what is the time difference between p and s. An earthquake occurs when rocks break and move as a result of stresses caused by plate motions which, in turn, result from heat loss from within the earth. An earthquake occurs when earth shakes because of the release. Please visit to access educational resources for septic system users. Place a piece of cardboard over the four walls as a ceiling.
Earthquake earthquakes are sudden, violent shaking of the earths crust. Earthquake preparedness your people ensure you have an emergency communication plan in place prior to the earthquake and that employees are aware of their part in the plan determine who is certified in cert, cpr, etc. This course is expected to take 30 minutes to complete. Various societies have produced earthquake legends to explain these natural occurrences. Normal and reverse faults are types of dipslip faults. They are caused when the earths tectonic plates move, rub, collide, or break apart. Indeed, the 1971 sylmar earthquake and 1994 northridge earthquakes came as surprises, said peggy hellweg, operations manager at the berkeley seismological laboratory.
Map of large, known and active faults in kazakhstan 12 figure 3. Earthquake magnitude earthquake severity richter magnitude earthquake effects less than 3. Study 31 terms earthquakes concepts flashcards quizlet. Liquefaction only occurs in soil that is fully saturated. We studied the earthquake mortality rates for more than 4,500 worldwide earthquakes since 1973 and developed an empirical country and regionspecific earthquake vulnerability model. Liquefaction is a dangerous phenomenon that occurs when saturated soil is weakened during an earthquake or high load activity. Fewer than 20 earthquakes occur each year, on average, that are considered major magnitude 7.
That can make the edges of one or both crumple, causing earthquakes and building mountains. When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earths crust and cause the shaking that we feel in california there are two plates the pacific plate and the. An earthquake occurs when earths surface shakes because of the release. Baxter introduction every year approximately 3,000,000 earthquake s occur worldwide. Ask students what they think liquefaction is and why it is dangerous. These are good for anyone living in an area prone to earthquakes or for those. By studying the animation and the paper model, students will come to understand that. But that is not entirely satisfactory, says zeev reches, a professor of geoscience at the university of oklahoma, because large earthquakes can form where the rocks are too cool to form glass. And they are not limited to the west coast of the u. The assessment of earthquake risk constitutes the first step to support decisions and actions to reduce potential losses. Within the earth rocks are constantly subjected to. Earthquakes are not evenly distributed across the planet. There are a number of earthquake detector projects for the raspberry pi. One possibility would be to spend one period in inquiry with the rubber bands and blocks of wood, and then a second one doing this more directed.
The tectonic plates are always slowly moving, but they get stuck at their edges due to friction. The same participants who will respond or work to rebuild the community when an actual earthquake occurs should be involved in. The process may require several components, such as earthquake catalogues historical. Each earthquake produces three basic types of seismic waves. During the izmit earthquake, the crust broke along the north anatolian fault in northern turkey fig. If a strong new madrid earthquake, with a magnitude equal to the historic 18111812 earthquakes 7. Anatomy of an earthquake the location within earth along a fault at which the first motion of an earthquake occurs is called the focus plural, foci. In laboratories, burners should be extinguished, if possible, before.
Before we can understand earthquakes, we first must explore deformation of rocks and faulting. Ninety eight percent of them are less than a magnitude 3. Sometimes one plate slips beneath the other, diving into the hot mantle. School earthquake safety guidebook december 2000 1 introduction the first indication of an earthquake may be a sudden violent jolt and a shaking and moving of objects. Students should stay in the drop position until the emergency is over or until further instructions are given.
Causing a range of effects from unnoticeable, mild tremors to violent, prolonged shaking, an earthquake is a natural phenomenon that occurs frequently only in certain areas of the world. The largest, main earthquake is called the mainshock. Every year approximately 3,000,000 earthquakes occur worldwide. What is an earthquake and what causes them to happen. This happens when liquefaction occurs in the subsurface layer, the movement of which can result in the opening of large fissures in the. Earthquake hazard assessment enables the likelihood of ground shaking across a region to be calculated, which is a fundamental component in earthquake risk assessment or hazard mapping for design codes. Earthquakes arent predictable, so the best practice is to always be prepared. The place where an earthquake begins underground is called the hypocenter. The science behind earthquakes what is an earthquake. Its like when youre teacher loses their marbles because youve asked them the same question 7 times in a row.
Earthquakes earthquake measurements slides and pdf files. Sp23 earthquake basics the delaware geological survey. Earthquakes can happen at any time of the year and occur without warning. Most earthquakes happen when parts of the earth move quickly.
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