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Surface motion map for a hypothetical earthquake on the northern portion of the Hayward Fault Zone and its presumed northern extension, the Rodgers Creek Fault Zone. 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.
The ISC-GEM Global Instrumental Earthquake Catalogue (1900-2013) (prepared at the request of the GEM Foundation) catalogs magnitude 5.5 or greater earthquakes suitable for modeling and assessing seismic hazard and risk. Epicentral locations and hypocentral depths were recalculated from original travel time data using a consistent velocity model.
It is often used within earthquake engineering (including seismic building codes) and it is commonly plotted on seismic hazard maps. [6] In an earthquake, damage to buildings and infrastructure is related more closely to ground motion, of which PGA is a measure, rather than the magnitude of the earthquake itself. For moderate earthquakes, PGA ...
Global components will provide preliminary data on a global scale, but on a local scale, regional and national programmes will provide more detailed and reliable data. One Global component was the Global GMPEs project that proposed a set of ground motion prediction equations for use when calculating seismic hazard. [4]
According to the USGS, "ShakeMaps provide near-real-time maps of ground motion and shaking intensity following significant earthquakes. These maps are used by federal, state, and local organizations, both public and private, for post-earthquake response and recovery, public and scientific information, as well as for preparedness exercises and ...
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 governments) analyze their 'portfolio' of properties, to determine how to best allocate limited funds for structural strengthening of buildings, or other risk reduction measures such as emergency planning.
Isoseismal map for the 1968 Illinois earthquake. In seismology, an isoseismal map is used to show countour lines of equally felt seismic intensity, generally measured on the Modified Mercalli scale. Such maps help to identify earthquake epicenters, particularly where no instrumental records exist, such as for historical earthquakes.
Seismotectonics is the study of the relationship between the earthquakes, active tectonics and individual faults of a region. It seeks to understand which faults are responsible for seismic activity in an area by analysing a combination of regional tectonics, recent instrumentally recorded events, accounts of historical earthquakes and geomorphological evidence.