An earthquake occurs when earths surface shakes because of the release of. Eventually they become so strong that they cause rocks to break underground. But a more detailed look reveals that the distribution of earthquake foci in the world is by no means random. Earthquake magnitude earthquake severity richter magnitude earthquake effects less than 3. The spot underground where the rocks break is the focus of the earthquake. When the pieces slide apart, they create tremendous force. Multiple choice questions for earthquakes chapter 16 each chapter will include a few questions designed to test your knowledge of material covered in the chapter and in the internetbased resources. Many of the hazards to workers both during and following an earthquake are predictable and may be reduced through hazard identification, planning, and mitigation. Earthquake, any sudden shaking of the ground caused by the passage of seismic waves through earths rocks.
Its always a practical idea to keep a supply of nonperishable food on hand that. They are most powerful at the center of the earthquake, but they travel through much of. They strike without warning and many of the earths earthquake zones coincide with areas of high population density. Risk, detection, warning, and research congressional research service summary portions of all 50 states and the district of columbia are vulnerable to earthquake hazards, although risks vary greatly across the country and within individual states. Additionally, if an earthquake occurs in a distant place especially if the hypocenter is shallow large and slow swaying can occur after the ground. Besides parents, liu shaokun, a sichuan school teacher, was detained on june 25, 2008, for disseminating rumors and destroying social order about the sichuan earthquake. They are most powerful at the center of the earthquake, but they travel through much of the earth and back to the surface. Earthquakes occur when two blocks of earth suddenly slip past each other.
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. Store at least 1 gallon of water per person per day and be prepared for a 72hour period. Earthquakes occur when rock underground suddenly breaks along a fault. An aerial view of the san andreas fault in the carrizo plain, central california. Learn what to do during an earthquake, and how to strengthen your home to prepare for an earthquake. Drop, cover and hold on under a desk, a table or along an interior wall. An earthquake occurs because of geologic forces inside the earth.
Since knowledge and preparation are keys to your survival during and after an earth. Earthquake safety procedures introduction it is not possible to prevent earthquakes or change the likelihood of an earthquake occurring. The movement of earths crust resulting from the release of built up potential energy between two stuck tectonic plates. Some earthquakeprone areas have adapted various ways to protect their communities. Top 10 tips for earthquake safety police department uci. Earthquakes an earthquake is shaking or trembling of the earths surface, caused by the seismic waves or earthquake waves that are generated due to a sudden movement sudden release of energy in the earths crust shallowfocus earthquakes or upper mantle some shallowfocus and all intermediate and deepfocus earthquakes. The report is intended to help students and others visualize what causes earthquake shaking and. Earthquake safety activities for children and teachers this publication provides readytouse, handson activities for students and teachers explaining what happens during an earthquake, how to prepare for earthquake shaking, and how to stay safe during and after an earthquake. Multiple choice questions for earthquakes chapter 16. Describe possible consequences of an earthquake at the school.
Have on hand for any emergency ideas for home, workplace, and car. 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. An aftershock is in the same region of the main shock but always of a smaller magnitude. Various societies have produced earthquake legends to explain these natural. Over the course of geological time, earthquakes, floods, and other natural events have helped to shape the surface of our planet. The forces generated in earths crust are typically. Earthquakes natural disasters and severe weather cdc. Seismologists can tell how serious an earthquake is by a machine called a seismograph, which rates the intensity of the quakes shaking.
The location below the earths surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicenter. Within the earth rocks are constantly subjected to forces that tend to bend, twist, or fracture them. Earthquake safety earthquake preparedness red cross. Geologists study earthquakes to understand where they are likely to happen and how people can be prepared and protected when an earthquake strikes. An early earthquake image of california is a collapsed adobe home with the door frame as the only standing part. Sep 29, 2008 but a more detailed look reveals that the distribution of earthquake foci in the world is by no means random. These are smaller earthquakes that happen in the same place as the larger earthquake that follows. Far in advance, you can gather emergency supplies, identify and reduce possible hazards in your home, and practice what to do during and after an earthquake.
An earthquake is the vibration, sometimes violent, of the earths surface that follows a release of energy in the earths crust. 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. Plastic strain occurs when stress is applied to an object, and it becomes deformed. Sp23 earthquake basics the delaware geological survey. However, we can greatly increase our chances of safety and survival, by being aware and prepared. When an earthquake occurs, the seismic waves radiate out in all directions from the focus, which is where.
When this happens, tremendous energy is released suddenly. Can cause major damage to poorly constructed buildings over small regions. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Liquefaction occurs when a material of solid consistency is transformed, with increased water pressure, in to a liquefied state. Seismology is the study of earthquakes and seismic waves.
The energy takes the form of motion that spreads out in all directions from the break. The collection of material points at the fault over which slip occurs usually constitutes an oblong threedimensional. Also, the seismic waves from earthquakes can be used to image the deep. Using this method, they were said to have predicted the time of the 2008 sichuan earthquake with an accuracy of 1 day. Before we can understand earthquakes, we first must explore deformation of rocks and faulting. Practice drop, cover and hold on with all members of. Top 10 tips for earthquake safety uci public safety. The tectonic plates are always slowly moving, but they get stuck at their edges due to friction. Severe earthquakes destroy power and telephone lines, gas, sewer, or water mains, which, in turn, may set off fires. A special earthquake occurs on curved fault article pdf available in chinese science bulletin 582829 october 20 with 69 reads how we measure reads. Buildings and bridges are designed to sway, rather than break, when an earthquake occurs. The same study, however, acknowledges the limitation of earthquake prediction models, and does not mention that the location of the quake could be accurately predicted. An earthquake is what happens when two blocks of the earth suddenly slip past one another.
The surface where they slip is called the fault or fault plane. Folded rocks have been subjected to a plastic strain. Meanwhile, every day thousands of smaller tremors often. Meanwhile, every day thousands of smaller tremors often go unnoticed by most people. Throughout, we are driven by the question, what happens during an earthquake. Surviving an earthquake and reducing its health impact requires preparation, planning, and practice. The place directly above the focus on top of the ground is the epicenter of the earthquake. Some earthquake prone areas have adapted various ways to protect their communities. Earthquakes occur most often along geologic faults, narrow zones where rock masses move in relation to one another.
A seismograph, or seismometer, is an instrument used to. An earthquake is a shock wave that radiates to the earths surface from underground. Earthquakes are caused by tectonic movements in the earths crust. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to toss people around and destroy whole cities. Weather wiz kids is a fun and safe website for kids about all the weather info they need to know. To be considered an earthquake, a shock wave has to be of natural origin. What is an earthquake and what causes them to happen. The main cause is that when tectonic plates collide, one rides over the other, causing orogeny mountain building, earthquakes and volcanoes. Earth scientists know this as the elastic rebound theory. Elastic strain happens when an object is deformed, and then when the stress. Earthquakes 5 earthquake characteristics an earthquake is a trembling of the ground that results from the sudden shifting of rock beneath the earths crust.
An aftershock is an earthquake that occurs after a previous earthquake, the mainshock. According to universe today, earthquakes occur as a result of tectonic plates colliding and volcanic eruption. Scientists dont really know if an earthquake is a foreshock until the bigger earthquake occurs. The science behind earthquakes what is an earthquake. This sudden release of energy causes the seismic waves that make the ground shake. The effects of earthquake on the environment like surface. Dec 25, 2019 earthquakes an earthquake is shaking or trembling of the earths surface, caused by the seismic waves or earthquake waves that are generated due to a sudden movement sudden release of energy in the earths crust shallowfocus earthquakes or upper mantle some shallowfocus and all intermediate and deepfocus earthquakes. Move away from windows and unsecured tall furniture. Earthquakes are among the most deadly natural hazards. Lius family was later told that he was being investigated on suspicion of the crime of inciting subversion. There are around 100 earthquakes each year of a size that could cause serious damage. This section contains 16 worksheets about earthquakes which can be helpful to both you and your students. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock.
An earthquake is caused by a sudden slip on a fault. Sep 23, 2018 in case an earthquake occurs, we should take the following precautions to protect ourselves depending on whether we are at home or outdoors at that moment. Within the earth rocks are constantly subjected to. There are many things you can do to prepare your workplace before an earthquake occurs. Learning earthquake tip 1 earthquake design and construction. Its like when youre teacher loses their marbles because youve asked them the same question 7 times in a row. Page 42 earthquake effects liquefaction strong ground motion during an earthquake can cause watersaturated, unconsolidated soil to act more like a dense fluid than a solid. Instead, when plotted on a world map, earthquake locations look like narrow bands winding through the continents and. The location below the earths surface where the earthquake starts is called the hypocenter, and the.
Earthquake preparedness guide for seniors, people with. A seismograph, or seismometer, is an instrument used to detect. Learn more about the causes and effects of earthquakes in this article. 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. The place where an earthquake begins underground is called the hypocenter, and the area on the earths surface directly above the hypocenter is called the epicenter and receives the most powerful shock waves. If you are indoors when the shaking occurs, stay there. Most casualties and injuries during an earthquake occur when. Page 2 of 8 earthquake preparedness guide for people with disabilitiesafn earthquake country alliance 022020 step 2 plan to be safe step2.
Fun facts for kids on earthquakes image of a road damaged by earthquake. The seismograph records the seismic waves generated by earthquakes, allowing the seismologist to determine where, and how deep, a particular earthquake is. Apr 21, 2015 almost every year, a large earthquake occurs somewhere in the world and captures the publics attention. Almost every year, a large earthquake occurs somewhere in the world and captures the publics attention. Seismic waves shock waves from an earthquake that travel through the ground are called seismic waves. Remain calm as the quake occurs others will respond to your actions. An earthquake is a sudden shaking movement of the surface of the earth. Oct 19, 2011 an early earthquake image of california is a collapsed adobe home with the door frame as the only standing part. The surface where they slip is known as the fault or fault plane. Earthquakes affect almost every part of the earth and like rain they can be either mild or catastrophic. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom. From this came the belief that a doorway is the safest place to be during an. Geological survey confirms an earthquake occurred thursday, nov.