The reflection is the energy or wave from an earthquake that has been returned (reflected) from an boundary between two different materials within the earth, just as a mirror reflects light.
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Reflected Wave
The reflection is the energy or wave from an earthquake that has been returned (reflected) from an boundary between two different materials within the earth, just as a mirror reflects light.
Refraction
Refraction is (1) the deflection, or bending, of the ray path of a seismic wave caused by its passage from one material to another having different elastic properties. (2) bending of a tsunami wave front owing to variations in the water depth along a coastline.
Refraction is (1) the deflection, or bending, of the ray path of a seismic wave caused by its passage from one material to another having different elastic properties. (2) bending of a tsunami wave front owing to variations in the water depth along a coastline.
Residuals
The residual is the difference between the measured and predicted values of some quantity.
The residual is the difference between the measured and predicted values of some quantity.
Rupture Front
Snapshots of a rupture front moving across a fault surface.
Snapshots of a rupture front moving across a fault surface.
S Waves
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.
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.
Seiche in Lake Geneva, Switzerland
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.
New Madrid Seismic Zone
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.
Slip Rate Map
The slip rate is how fast the two sides of a fault are slipping relative to one another, as determined from geodetic measurements, from offset man-made structures, or from offset geologic features whose age can be estimated. It is measured parallel to the predominant slip direction or estimated from the vertical or horizontal offset of geologic markers.
The slip rate is how fast the two sides of a fault are slipping relative to one another, as determined from geodetic measurements, from offset man-made structures, or from offset geologic features whose age can be estimated. It is measured parallel to the predominant slip direction or estimated from the vertical or horizontal offset of geologic markers.
Standard Deviation
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.
Strike
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.
Los Gatos Residence Damage
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.
Surface Waves
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.
YBP
YBP is an abbreviation for "years before present".
Formation of Earth: 4.6x10^9 YBP
Dinosaur extinction: 6.5x10^7 YBP
First hominids: 2x10^6 YBP
Last great ice age: 1x10^4 YBP
Declaration of Independence: 2x10^2 YBP
Establishment of UWB: 1x10 YBP
YBP is an abbreviation for "years before present".
Formation of Earth: 4.6x10^9 YBP
Dinosaur extinction: 6.5x10^7 YBP
First hominids: 2x10^6 YBP
Last great ice age: 1x10^4 YBP
Declaration of Independence: 2x10^2 YBP
Establishment of UWB: 1x10 YBP
Amplitude (1)
High, medium, and low amplitude. The amplitude is the size of the wiggles on an earthquake recording.
High, medium, and low amplitude. The amplitude is the size of the wiggles on an earthquake recording.
Attenuation Ripples
Ripples on a pond are attenuated as they move away from the source. When you throw a pebble in a pond, it makes waves on the surface that move out from the place where the pebble entered the water. The waves are largest where they are formed and gradually get smaller as they move away. This decrease in size, or amplitude, of the waves is called attenuation.
Ripples on a pond are attenuated as they move away from the source. When you throw a pebble in a pond, it makes waves on the surface that move out from the place where the pebble entered the water. The waves are largest where they are formed and gradually get smaller as they move away. This decrease in size, or amplitude, of the waves is called attenuation.
Seismic Refraction
A seismic refraction or seismic reflection line is a set of seismographs usually lined up along the earth's surface to record seismic waves generated by an explosion for the purpose of recording reflections and refractions of these waves from velocity discontinuities within the earth. The data collected can be used to infer the internal structure of the earth.
A seismic refraction or seismic reflection line is a set of seismographs usually lined up along the earth's surface to record seismic waves generated by an explosion for the purpose of recording reflections and refractions of these waves from velocity discontinuities within the earth. The data collected can be used to infer the internal structure of the earth.
Blind Thrust Fault
A diagram of a blind thrust fault resulting in ductile rock layers folding over the fault and leaving the fault under the surface.
A diagram of a blind thrust fault resulting in ductile rock layers folding over the fault and leaving the fault under the surface.
Stress Types
A diagram showing three stress types: tensional stress, compressional stress, and shear stress.
A diagram showing three stress types: tensional stress, compressional stress, and shear stress.
Crust
A diagram showing the Earth's crust with continental and oceanic crust.
The crust is the outermost major layer of the earth, ranging from about 10 to 65 km in thickness worldwide. The uppermost 15-35 km of crust is brittle enough to produce earthquakes.
A diagram showing the Earth's crust with continental and oceanic crust.
The crust is the outermost major layer of the earth, ranging from about 10 to 65 km in thickness worldwide. The uppermost 15-35 km of crust is brittle enough to produce earthquakes.
Dip Diagram
Diagram of dip. Dip is the angle that a planar geologic surface (for example, a fault) is inclined from the horizontal.
Diagram of dip. Dip is the angle that a planar geologic surface (for example, a fault) is inclined from the horizontal.
Acceleration, Velocity, and Displacement Graphs
Acceleration, velocity, and displacement records.
Displacement is the difference between the initial position of a reference point and any later position. The amount any point affected by an earthquake has moved from where it was before the earthquake.
Acceleration, velocity, and displacement records.
Displacement is the difference between the initial position of a reference point and any later position. The amount any point affected by an earthquake has moved from where it was before the earthquake.