Therefore, of all earthquake preparedness measures, earthquake drills are the most important. Earthquakes are caused mostly by rupture of geological faults but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests. Amplification the period or frequency of the ground motion coinciding with the period of the building causing significant increase of acceleration and damage. If the epicenter of a larger earthquake is situated in the offsore seaocean seabed may be displaced sufficiently to cause tsunami. Accelerogram the record from an accelerograph showing acceleration as a function of time.
When the pieces slide apart, they create tremendous force. A seismograph, or seismometer, is an instrument used to. Earthquake also known as quake, tremor or temblor is the phenomenon where there is a sudden release of extreme energy from the earth crust resulting in shaking and displacement of the ground along with the creation of sesmic waves. Definition of earthquake ground trembling or shaking due to sudden release of energy accumulated in deformed rock. Earthquakeresistant design means additional investment.
This book deals with earthquake resistant structures, such as, buildings, bridges and liquid storage tanks. You know how when you have a really bad day and it seems like everything is going wrong. Earthquake is a term used to describe both sudden slip on a fault, and the resulting ground shaking and radiated seismic energy caused by the slip, or by volcanic or magmatic activity, or other sudden stress changes in the earth. In some tsunamiprone countries, earthquake engineering measures have been taken to reduce the damage caused onshore. Definition of earthquake written for english language learners from the merriamwebster learners dictionary with audio pronunciations, usage examples, and countnoncount noun labels. The sudden shaking or rolling of the earths surface is called an earthquake. Earthquake hazard is anything associated with an earthquake that may affect the normal activities of people. Earthquakes occur most often along geologic faults, narrow zones where rock masses move in relation to one another. Chapter 8 earthquakes and earths interior section 8. Liquefaction and related phenomena have been responsible for tremendous amounts of damage in historical earthquakes around the world. An earthquake is a sudden shaking of the earths surface that often causes a lot of damage. Earthquake definition of earthquake by the free dictionary. In an earthquake, huge masses of rock move beneath the earth s surface and cause the ground to shake. The epicenter is the point on earths surface directly above the focus.
Recent developments in the definition of design ground motions or seismic analysis of structures are presented. Earthquake protection, definition, causes, effects. There will not be time to think through what to do. If all the dishes fall out of your cabinet, you may honestly be able to say. Earthquake terms common earthquake terms focus the focus or hypocentre of an earthquake is where the earthquake originated from, usually underground on the fault zone. An earthquake is what happens when two blocks of the earth suddenly slip past one another. Definition, causes, measures and other details with diagram. The policy includes coverage for damage by shock and by fire occasioned by or happening through an earthquake. Over 14,000 residents of the region were killed as poorly constructed. The impact of an earthquake can be measured by a seismometer.
Earthquake fault earthquake faults are fractures where displacement is on either side relative to one another and parallel to the fracture. Fault that makes california an area of high risk for earthquakes. Can cause major damage to poorly constructed buildings over small regions. Sp23 earthquake basics the delaware geological survey. Its like when youre teacher loses their marbles because youve asked them the same question 7 times in a row. The length of the wiggle depends on the size of the fault. Earthquakes affect almost every part of the earth and like rain they can be either mild or catastrophic. This will protect us from the losses and help to cope up with these hazards. The surface wave magnitude was developed in the 1950s as a means to measure remote earthquakes and to. The deadly izmit earthquake struck northwest turkey on august 17, 1999, at 3 a. Learn more about the causes and effects of earthquakes in this article. Earthquake glossary, definition, meaning and related terms.
National oceanic and atmospheric administration, national geophysical data center, significant earthquake database, a searchable online database using the catalog of significant earthquakes 2150 b. The two earthquakes struck within days of each other, unleashing roughly the same devastating power. By looking at the amount of time between the p and s wave on a seismogram recorded on a seismograph, scientists can tell how far away the earthquake was from that location. The epicenter is the point at ground level directly above the hypocenter. This shaking can result in the damage of various structures such as buildings and further breakdown of the earths surface. Within days of the earthquake she had been flown out of the country and was back home with her parents. Aftershock one of a series of smaller quakes following the main shock of the earthquake.
Definition of words in italics are found in the glossary. Epicentre the point on the earths surface vertically above the focus of an earthquake, i. A sudden movement of the earths crust caused by the release of stress accumulated along geologic faults or by volcanic activity. Earthquakes are caused by the release of builtup stress within rocks along geologic faults or by the movement of magma in volcanic areas. More than 200,000 earthquakes are recorded each year, though it is estimated that several million occur globally. This section explains what earthquakes and faults are and what causes earthquakes.
Earthquake definitions victoria state emergency service. Pdf recent developments in the definition of design. An earthquake is caused by a sudden slip on a fault. Earthquake definition for englishlanguage learners from. It means a relatively slow swaying motion during earthquake shake. Earthquake definition of earthquake by merriamwebster. An earthquake is a shaking of the ground caused by movement of the earths crust.
Pdf definition of yield seismic coefficient spectrum. 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 earthquake occurs when earths surface shakes because of the release. Seismologists can tell how serious an earthquake is by a machine called a seismograph, which rates the intensity of the quakes shaking. Definition of yield seismic coefficient spectrum considering the uncertainty of the earthquake motion phase article pdf available in applied sciences 911. Earthquake ruptures typically propagate at velocities that are in the range 7090% of the swave velocity, which is independent of earthquake size. Fault plane a fault is a weak point within a tectonic. An earthquake is the result of a sudden release of stored energy in the earths crust that creates seismic waves. This includes surface faulting, ground shaking, landslide, liquefaction, tectonic deformation, tsunamis, and seiches. Because earthquakes strike without warning, lifeprotecting actions must be taken immediately at the first indication of ground shaking. It detects the vibrations caused and it puts these movements on a seismograph. There are many scientific terms that are difficult to understand, but once in a while scientists actually use words that make sense.
A summary of results of empirical and analytical siteeffect studies are provided and recent findings from empirical studies on. Earthquake definition of earthquake by medical dictionary. People who study earthquakes are called seismologists. Defining an earthquake defining an earthquake an earthquake is a natural occurrence, like rain. Epicentre the epicentre of an earthquake is the point on the surface of earth directly above the epicentre. Larger earthquakes usually begin with slight tremors but rapidly take the form of one or more violent shocks, and end in vibrations of gradually diminishing force called aftershocks. The epicentre of an earthquake is the point on the surface of earth. Earthquake magnitude earthquake severity richter magnitude earthquake effects less than 3. Often they are too small for people to feel at all. This was later revised and renamed the local magnitude scale, denoted as ml or m l. The science behind earthquakes what is an earthquake. Proper strategies and awareness about disaster management is the need of the hour. Many of these go undetected because their magnitude is small or they occur in areas which are not closely monitored.
Earthquake shaking or slipping movement of the earthas crust, followed by seismic waves and vibrations. An earthquakes point of initial rupture is called its hypocenter or focus. Every year it causes a huge loss of life and property all around the world. The mitigation plan development team researched the earthquake. These are smaller earthquakes that happen in the same place as the larger earthquake. Accelerograph a strong motion earthquake instrument recording ground or base acceleration. Earthquake waves can travel hundreds of kilometres causing or the l earthquakes to be felt a long way away from the origin.
Reading strategy building vocabulary as you read this section, write a definition for each vocabulary term in your own words. Earthquake meaning in the cambridge english dictionary. Earthquake definition and meaning collins english dictionary. An earthquake is the shaking of the surface of the earth resulting from a sudden release of. It contains twenty chapters covering several interesting research topics written by researchers and experts in the field of earthquake. Lomnitz and others published earthquakes find, read. The focus is the point on the fault surface where motion begins. These are smaller earthquakes that happen in the same place as the larger earthquake that follows. A small subset of earthquake ruptures appear to have propagated at speeds greater than the swave velocity. Actually earthquakes occur daily around the world according to one estimate, about 8000 occur every year, but most of them are too mild to be noticeable. Q12 are seismic intensity and earthquake magnitude different. Mar 24, 2020 earthquake, any sudden shaking of the ground caused by the passage of seismic waves through earths rocks. Earthquake simple english wikipedia, the free encyclopedia. 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.
Earthquake, any sudden shaking of the ground caused by the passage of seismic waves through earths rocks. Aftershock aftershocks are smaller earthquakes that may occur after the main earthquake in the same area. Most of the devastation caused by earthquakes is a direct result of the ground shaking violently. Seismology definition of seismology by merriamwebster. Sometimes, however, earthquakes cause great losses of life and property.
Earthquake glossary usgs earthquake hazard program. The surface where they slip is called the fault or fault plane. What is an earthquake and what causes them to happen. Rocks at relatively shallow depths in the earths crust cool and brittle deform until they reach a yield point and break forming faults. Japan, where tsunami science and response measures first began following a disaster in 1896, has produced evermore elaborate countermeasures and response plans. The violent earthquake unleashed itself under the sea near northern indonesia on december 26.
These supershear earthquakes have all been observed during large strikeslip events. Its just one thing after another, and you get so frustrated that by the end of the. Over the course of geological time, earthquakes, floods, and other natural events have helped to shape the surface of our planet. The location below the earths surface where the earthquake starts is called the hypocenter, and the. Fun facts for kids on earthquakes image of a road damaged by earthquake. Seismic definition, pertaining to, of the nature of, or caused by an earthquake or vibration of the earth, whether due to natural or artificial causes. 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. Factors that affect a structures seismic risk include. The seismic waves of an earthquake carry the force of the earthquake and cause damage on the surface seismology seismology is the study of earthquakes. On the contrary, drought is an event that builds up slowly, with clear early warning signs. Earthquake definition is a shaking or trembling of the earth that is volcanic or tectonic in origin.
Earthquakes are usually quite brief, but there may be many over a short time frame. This earthquake was the seventh in a series of repeating earthquakes on this stretch of the fault. Page 2 of 8 earthquake preparedness guide for people with disabilitiesafn earthquake country alliance 022020 step 2 plan to be safe step2. Glossary of seismic terminology acceleration the time rate of velocity change, commonly measured in g an acceleration of 32 ftsecsec or 980 cmsecsec gravity constant on earth. Definition of earthquake in the medical dictionary by the free dictionary. The socalled richter scale also richter magnitude or richter magnitude scale, more accurately but informally richters magnitude scale for measuring the strength size of earthquakes refers to the original magnitude scale developed by charles f. Earthquake major historical earthquakes britannica. The strength, or magnitude, of an earthquake, is measured using the richter scale. Earthquake definition, a series of vibrations induced in the earths crust by the abrupt rupture and rebound of rocks in which elastic strain has been slowly accumulating. An instrument used to detect and record earthquakes. If all the dishes fall out of your cabinet, you may honestly be able to. The movement of earths crust resulting from the release of built up potential energy between two stuck tectonic plates. Liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading.
Seismic definition is of, subject to, or caused by an earthquake. The tectonic plates are always slowly moving, but they get stuck at their edges due to friction. An earthquake is the sudden movement of the earths tectonic plates, resulting in shaking of the ground. Most seismic events earthquakes are very minor, and do not. Seismology definition is a science that deals with earthquakes and with artificially produced vibrations of the earth. Earthquakes are accordingly measured with a seismometer, commonly known as a. If you are close to the earthquake, the p and s wave will come one right after the other, but if you are far away, there will be more time between the two. Severe earthquakes destroy power and telephone lines, gas, sewer, or water mains, which, in turn, may set off fires. The intensity of ground shaking and other earthquake effects the structure.