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Seismic Risk
Seismic risk or earthquake risk is the potential impact on the built environment and on people's well-being due to future earthquakes. 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 corporat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthquakes
An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume. In its most general sense, the word ''earthquake'' is used to describe any seismic event that generates seismic waves. Earthquakes can occur naturally or be induced by human activities, such as mining, fracking, and nuclear weapons testing. The initial point of rupture is called the hypocenter or focus, while the ground level directly above it is the epi ... [...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 level of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquefaction
In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics. It occurs both naturally and artificially. As an example of the latter, a "major commercial application of liquefaction is the liquefaction of air to allow separation of the constituents, such as oxygen, nitrogen, and the noble gases." Another is the conversion of solid coal into a liquid form usable as a substitute for liquid fuels. In geology, soil liquefaction refers to the process by which water-saturated, unconsolidated sediments are transformed into a substance that acts like a liquid, often in an earthquake. Soil liquefaction was blamed for building collapses in the city of Palu, Indonesia in October 2018. In a related phenomenon, liquefaction of bulk materials in cargo ships may cause a dangerous shift in the load. In physics and chemistry, the phase transitions from solid and melting.htm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urban Seismic Risk
Urban seismic risk is the risk of earthquakes damaging or destroying people and things in towns and cities. Even if a big earthquake is likely urban seismic risk 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. Earthquake engineering can reduce the risk. International projects The IDNDR secretariat launched the RADIUS (risk assessment tools for diagnosis of urban areas against seismic disasters) initiative in 1996 to promote worldwide activities for the reduction of urban seismic risk, which experienced rapid growth particularly in developing countries, by helping to raise public awareness. Urban risk and planning One of the disaster risk reduction themes set forth by the United Nations International Strategy for Disaster Reduction projecPreventionWeb is urban risk and planning. This theme refers to the measurement and management of urban hazards and vulnerabi ... [...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 California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthquake Preparedness
Preparations for earthquakes 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 preparedness, can also be part of earthquake preparedness. Building design and retrofitting Seismic codes in earthquake prone areas may have specific requirements designed to increase new buildings' resistance to earthquakes. Older buildings and homes that are not up to code may be modified to increase their resistance ... [...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 displacement and shaking such as caused by quakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The ou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Retrofit
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes (or generally, quakes) and the generation and propagation of elastic waves through planetary bodies. It also includes studies of the environmental effects of earthquakes such as tsunamis; other seismic sources such as volcanoes, plate tectonics, glaciers, rivers, oceanic microseisms, and the atmosphere; and artificial processes such as explosions. Paleoseismology is a related field that uses geology to infer information regarding past earthquakes. A recording of Earth's motion as a function of time, created by a seismograph is called a seismogram. A seismologist is a scientist who works in basic or applied seismology. History Scholarly interest in earthquakes can be traced back to antiquity. Early speculations on the natural causes of earthquakes were included in the writings of Thales of Miletus ... [...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] |
