An S wave, or shear wave, is a seismic body wave that shakes the ground back and forth perpendicular to the direction the wave is moving.
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An S wave, or shear wave, is a seismic body wave that shakes the ground back and forth perpendicular to the direction the wave is moving.
The spectrum is a curve showing amplitude and phase as a function of frequency or period, or how much of each type of shaking there is from an earthquake.
The spectrum is a curve showing amplitude and phase as a function of frequency or period, or how much of each type of shaking there is from an earthquake.
The standard deviation is how much a set of data is different from the curve it should make when plotted on a graph. Or, the square root of the average of the squares of deviations about the mean of a set of data. Standard deviation is a statistical measure of spread or variability.
The standard deviation is how much a set of data is different from the curve it should make when plotted on a graph. Or, the square root of the average of the squares of deviations about the mean of a set of data. Standard deviation is a statistical measure of spread or variability.
Station EMS in southern California.
The station refers to the place where a geophysical instrument is located.
Station EMS in southern California.
The station refers to the place where a geophysical instrument is located.
When the force trying to make the block (m) slip becomes greater than the frictional force causing it to stick, the block will slip.
When the force trying to make the block (m) slip becomes greater than the frictional force causing it to stick, the block will slip.
The dots on the left make a regular pattern, but the dots on the right make a random, or stochastic, pattern.
The dots on the left make a regular pattern, but the dots on the right make a random, or stochastic, pattern.
Strain is the small changes in length and volume associated with deformation of the earth by tectonic stresses or by the passage of seismic waves.
Strain is the small changes in length and volume associated with deformation of the earth by tectonic stresses or by the passage of seismic waves.
The strike is the trend or bearing, relative to north, of the line defined by the intersection of a planar geologic surface (for example, a fault or a bed) and a horizontal surface such as the ground.
The strike is the trend or bearing, relative to north, of the line defined by the intersection of a planar geologic surface (for example, a fault or a bed) and a horizontal surface such as the ground.
This turn-of-the-century wooden residence in Los Gatos sustained major damage when it moved off its foundation during the October 17, 1989, M7.1 Loma Prieta, California earthquake.
This turn-of-the-century wooden residence in Los Gatos sustained major damage when it moved off its foundation during the October 17, 1989, M7.1 Loma Prieta, California earthquake.
Subduction zone of the Juan de Fuca Plate and North America Plate, creating the Mt. St. Helens and Mt. Hood volcanoes.
Subduction zone of the Juan de Fuca Plate and North America Plate, creating the Mt. St. Helens and Mt. Hood volcanoes.
A surface wave is a seismic seismic wave that is trapped near the surface of the earth.
A surface wave is a seismic seismic wave that is trapped near the surface of the earth.
A sand boil is sand and water that come out onto the ground surface during an earthquake as a result of liquefaction at shallow depth.
A sand boil is sand and water that come out onto the ground surface during an earthquake as a result of liquefaction at shallow depth.
Secular refers to long-term changes that take place slowly and imperceptibly. Commonly used to describe changes in elevation, tilt, and stress or strain rates that are related to long-term tectonic deformation.
Secular refers to long-term changes that take place slowly and imperceptibly. Commonly used to describe changes in elevation, tilt, and stress or strain rates that are related to long-term tectonic deformation.
Seiche in Lake Geneva (Switzerland)
A seiche is the sloshing of a closed body of water from earthquake shaking. Swimming pools often have seiches during earthquakes.
Seiche in Lake Geneva (Switzerland)
A seiche is the sloshing of a closed body of water from earthquake shaking. Swimming pools often have seiches during earthquakes.
Moment = ? A D
? = shear modulus = 32 GPa in crust, 75 GPa in mantle
A = LW = area
D = average displacement during rupture
Moment = ? A D
? = shear modulus = 32 GPa in crust, 75 GPa in mantle
A = LW = area
D = average displacement during rupture
The New Madrid seismic zone in Central U.S.
A seismic zone is an area of seismicity probably sharing a common cause.
The New Madrid seismic zone in Central U.S.
A seismic zone is an area of seismicity probably sharing a common cause.
A seismogram is a record written by a seismograph in response to ground motions produced by an earthquake, explosion, or other ground-motion sources.
A seismogram is a record written by a seismograph in response to ground motions produced by an earthquake, explosion, or other ground-motion sources.
The shadow zone is the area of the earth from angular distances of 104 to 140 degrees from a given earthquake that does not receive any direct P waves. The shadow zone results from S waves being stopped entirely by the liquid core and P waves being bent (refracted) by the liquid core.
The shadow zone is the area of the earth from angular distances of 104 to 140 degrees from a given earthquake that does not receive any direct P waves. The shadow zone results from S waves being stopped entirely by the liquid core and P waves being bent (refracted) by the liquid core.
A slab is the oceanic crustal plate that underthrusts the continental plate in a subduction zone and is consumed by the earth's mantle.
A slab is the oceanic crustal plate that underthrusts the continental plate in a subduction zone and is consumed by the earth's mantle.
Slickensides are polished striated rock surfaces caused by one rock mass moving across another on a fault.
Slickensides are polished striated rock surfaces caused by one rock mass moving across another on a fault.
Teleseismic is pertaining to earthquakes at distances greater than 1,000 km from the measurement site.
Teleseismic is pertaining to earthquakes at distances greater than 1,000 km from the measurement site.