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Seismic Risk
Seismic risk refers to the risk of damage from earthquake to a building, system, or other entity. Seismic risk has been defined, for most management purposes, as the potential economic, social and environmental consequences of hazardous events that may occur in a specified period of time. A building located in a region of high seismic hazard is at lower risk if it is built to sound seismic engineering principles. On the other hand, a building located in a region with a history of minor seismicity, in a brick building located on fill subject to liquefaction can be as high or higher risk. A special subset is urban seismic risk which looks at the specific issues of cities. Risk determination and emergency response can also be determined through the use of an Earthquake scenario. Determination of seismic risk The determination of seismic risk is the foundation for risk mitigation decision-making, a key step in risk management. Large corporations and other enterprises (e.g., local ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Hazard
A seismic hazard is the probability that an earthquake will occur in a given geographic area, within a given window of time, and with ground motion intensity exceeding a given threshold. With a hazard thus estimated, risk can be assessed and included in such areas as building codes for standard buildings, designing larger buildings and infrastructure projects, land use planning and determining insurance rates. The seismic hazard studies also may generate two standard measures of anticipated ground motion, both confusingly abbreviated MCE; the simpler probabilistic Maximum Considered Earthquake (or Event ), used in standard building codes, and the more detailed and deterministic Maximum Credible Earthquake incorporated in the design of larger buildings and civil infrastructure like dams or bridges. It is important to clarify which MCE is being discussed. Calculations for determining seismic hazard were first formulated by C. Allin Cornell in 1968 and, depending on their l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urban Seismic Risk
Urban seismic risk is a subset of the general term seismic risk which describes the problems specific to centers of population when they are subjected to earthquakes. Many risks can be minimized with good earthquake construction, and seismic analysis. One of the best ways to deal with the issue is through an earthquake scenario analysis. Toronto Toronto, Ontario, Canada is used as an example city in this article. The general issues are common to all cities subject to earthquakes. Cities are a mixture of old and new construction as in this picture. Note the old brick building mixed in with the new highrises, and the famous Toronto CN Tower. Similar to methodologies used in nuclear reactors, a seismic walk down of the city is the best way to identify vulnerabilities and possible places for improvement. Toronto is located on the shores of Lake Ontario, the site of much microseismicity. Historic records indicate that energetic earthquakes occur infrequently in the region, as w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthquake Scenario
Earthquake scenario is a planning tool to determine the appropriate emergency responses or building systems in areas exposed to earthquake hazards. It uses the basics of seismic hazard studies, but usually places a set earthquake on a specific fault, most likely near a high-population area. Most scenarios relate directly to urban seismic risk, and seismic risk in general. Some earthquake scenarios follow some of the latest methodologies from the nuclear industry, namely a Seismic Margin Assessment (SMA). In the process, a Review Level Earthquake (RLE) is chosen that challenges the system, has a reasonable probability, and is not totally overwhelming. Scenarios have been developed for Seattle, New York City, and many of the faults in California. In general, areas west of the Rockies use urban earthquakes of M7 (moment magnitude The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthquake Preparedness
Earthquake preparedness is a set of measures taken at the individual, organisational and societal level to minimise the effects of an earthquake. Preparedness measures can range from securing heavy objects, structural modifications and storing supplies, to having insurance, an emergency kit, and evacuation plans. Preparedness measures Preparedness can consist of survival measures, preparation that will improve survival in the event of an earthquake, or mitigating measures, that seek to minimise the effect of an earthquake. Common survival measures include storing food and water for an emergency, and educating individuals what to do during an earthquake. Mitigating measures can include firmly securing large items of furniture (such as bookcases and large cabinets), TV and computer screens that may otherwise fall over in an earthquake. Likewise, avoiding storing items above beds or sofas reduces the chance of objects falling on individuals. Planning for a related tsunami, tsunami prep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground Motion
Ground motion is the movement of the earth's surface from earthquakes or explosions. Ground motion is produced by seismic waves that are generated by sudden slip on a fault or sudden pressure at the explosive source and travel through the earth and along its surface. This can be due to natural events, such as earthquakes and volcanic eruptions, or human activities, such as the detonation of nuclear weapons. There are two main types of seismic waves: body waves and surface waves. Body waves travel through the interior of the earth, while surface waves travel along the earth's surface. Ground motion is typically caused by surface waves, which are the most destructive type of seismic waves. Ground motion is measured using a seismometer A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The outpu . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Retrofit
Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with our recent experiences with large earthquakes near urban centers, the need of seismic retrofitting is well acknowledged. Prior to the introduction of modern seismic codes in the late 1960s for developed countries (US, Japan etc.) and late 1970s for many other parts of the world (Turkey, China etc.), many structures were designed without adequate detailing and reinforcement for seismic protection. In view of the imminent problem, various research work has been carried out. State-of-the-art technical guidelines for seismic assessment, retrofit and rehabilitation have been published around the world – such as the ASCE-SEI 41 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Probabilistic Risk Assessment
Probabilistic risk assessment (PRA) is a systematic and comprehensive methodology to evaluate risks associated with a complex engineered technological entity (such as an airliner or a nuclear power plant) or the effects of stressors on the environment (probabilistic environmental risk assessment, or PERA). Risk in a PRA is defined as a feasible detrimental outcome of an activity or action. In a PRA, risk is characterized by two quantities: #the magnitude (severity) of the possible adverse consequence(s), and #the likelihood (probability) of occurrence of each consequence. Consequences are expressed numerically (e.g., the number of people potentially hurt or killed) and their likelihoods of occurrence are expressed as probabilities or frequencies (i.e., the number of occurrences or the probability of occurrence per unit time). The total risk is the expected loss: the sum of the products of the consequences multiplied by their probabilities. The spectrum of risks across classes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Hazard
A seismic hazard is the probability that an earthquake will occur in a given geographic area, within a given window of time, and with ground motion intensity exceeding a given threshold. With a hazard thus estimated, risk can be assessed and included in such areas as building codes for standard buildings, designing larger buildings and infrastructure projects, land use planning and determining insurance rates. The seismic hazard studies also may generate two standard measures of anticipated ground motion, both confusingly abbreviated MCE; the simpler probabilistic Maximum Considered Earthquake (or Event ), used in standard building codes, and the more detailed and deterministic Maximum Credible Earthquake incorporated in the design of larger buildings and civil infrastructure like dams or bridges. It is important to clarify which MCE is being discussed. Calculations for determining seismic hazard were first formulated by C. Allin Cornell in 1968 and, depending on their l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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