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Peak ground acceleration (PGA) is equal to the maximum ground acceleration that occurred during earthquake shaking at a location. PGA is equal to the amplitude of the largest absolute acceleration recorded on an accelerogram at a site during a particular earthquake. [1] Earthquake shaking generally occurs in all three directions.
It is routinely used to provide post-earthquake situational awareness for emergency management and response and for damage and loss estimation. ShakeMap is also the primary shaking hazard input for many other downstream USGS earthquake products, including ShakeCast's assessments of critical facilities, PAGER 's societal losses, and estimates of ...
List of international earthquake acceleration coefficients. A list of earthquake coefficients used in structural design for earthquake engineering [1] around the world. For example, a coefficient of 0.09 indicates that a building is designed that 0.09457 of its weight can be applied horizontally during an earthquake. [clarification needed]
The 1971 San Fernando earthquake (also known as the 1971 Sylmar earthquake) occurred in the early morning of February 9 in the foothills of the San Gabriel Mountains in Southern California. The unanticipated thrust earthquake had a magnitude of 6.5 on the M s scale and 6.6 on the M w scale, and a maximum Mercalli intensity of XI ( Extreme ).
The JMA scale is expressed in levels of seismic intensity from 0 to 7 in a manner similar to that of the Mercalli intensity scale, which is not commonly used in Japan.The JMA uses seismic intensity meters to automatically calculate ground acceleration in real-time, reporting intensities based on measurements from observation points.
Logo of the ANSS. The Advanced National Seismic System (ANSS) is a collaboration of the United States Geological Survey (USGS) and regional, state, and academic partners that collects and analyzes data on significant earthquakes to provide near real-time (generally within 10 to 30 minutes [1]) information to emergency responders and officials, the news media, and the public. [2]
Ground motion hazard map for Hawaii, based on a 2% probability of exceeding 0.2 second spectral acceleration at 5 Hz in 50 years. Spectral acceleration (SA) is a unit measured in g (the acceleration due to Earth's gravity, equivalent to g-force) that describes the maximum acceleration in an earthquake on an object – specifically a damped, harmonic oscillator moving in one physical dimension.
Seismic intensity scales categorize the intensity or severity of ground shaking (quaking) at a given location, such as resulting from an earthquake.They are distinguished from seismic magnitude scales, which measure the magnitude or overall strength of an earthquake, which may, or perhaps may not, cause perceptible shaking.