Mitigation of seismic motion
Encyclopedia
Mitigation of seismic motion is an important factor in earthquake engineering
and construction
in earthquake
-prone areas. The destabilizing action of an earthquake on constructions may be direct (seismic motion of the ground) or indirect (earthquake-induced landslide
s, liquefaction of the foundation soils
and waves of tsunami
).
Knowledge of local amplification
of the seismic motion from the bedrock is very important in order to choose the suitable design solutions. Local amplification can be anticipated from the presence of particular stratigraphic conditions, such as soft soil overlapping the bedrock
, or where morphological settings (e.g. crest zones, steep slopes, valleys, or endorheic basins) may produce focalization
of the seismic event.
The identification of the areas potentially affected by earthquake-induced landslides and by soil liquefaction
can be made by geological survey and by analysis of historical documents. Even quiescent and stabilized landslide areas may be reactivated by severe earthquake. Young soil may be particularly susceptible to liquefaction.
Earthquake engineering
Earthquake engineering is the scientific field concerned with protecting society, the natural and the man-made environment from earthquakes by limiting the seismic risk to socio-economically acceptable levels...
and construction
Construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...
in earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
-prone areas. The destabilizing action of an earthquake on constructions may be direct (seismic motion of the ground) or indirect (earthquake-induced landslide
Landslide
A landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments...
s, liquefaction of the foundation soils
Soil liquefaction
Soil liquefaction describes a phenomenon whereby a saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid....
and waves of tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
).
Knowledge of local amplification
Amplifier
Generally, an amplifier or simply amp, is a device for increasing the power of a signal.In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to...
of the seismic motion from the bedrock is very important in order to choose the suitable design solutions. Local amplification can be anticipated from the presence of particular stratigraphic conditions, such as soft soil overlapping the bedrock
Bedrock
In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...
, or where morphological settings (e.g. crest zones, steep slopes, valleys, or endorheic basins) may produce focalization
Focalization
Focalization is a term coined by the French narrative theorist Gerard Genette. It refers to the perspective through which a narrative is presented. For example, a narrative where all information presented reflects the subjective perception of that information by a certain character is said to be...
of the seismic event.
The identification of the areas potentially affected by earthquake-induced landslides and by soil liquefaction
Soil liquefaction
Soil liquefaction describes a phenomenon whereby a saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid....
can be made by geological survey and by analysis of historical documents. Even quiescent and stabilized landslide areas may be reactivated by severe earthquake. Young soil may be particularly susceptible to liquefaction.
See also
- Base isolationBase isolationBase isolation, also known as seismic base isolation or base isolation system, is one of the most popular means of protecting a structure against earthquake forces...
- Seismic hazardSeismic hazardSeismic hazard refers to the study of expected earthquake ground motions at the earth's surface, and its likely effects on existing natural conditions and man-made structures for public safety considerations; the results of such studies are published as seismic hazard maps, which identify the...
- Seismic performance
- Tuned mass damperTuned mass damperA tuned mass damper, also known as an active mass damper or harmonic absorber, is a device mounted in structures to reduce the amplitude of mechanical vibrations. Their application can prevent discomfort, damage, or outright structural failure...
- Vibration controlVibration controlIn earthquake engineering, vibration control is a set of technical means aimed to mitigate seismic impacts in building and non-building structures.All seismic vibration control devices may be classified as passive, active or hybrid where:...
- Crash testing