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Radiometric is pertaining to the
measurement of geologic time by the analysis of certain
radioisotopes in rocks and their known rates of decay.
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A Rayleigh wave is a seismic surface wave causing the ground to
shake in an elliptical motion, with no transverse, or
perpendicular, motion.
Rayleigh waves
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The recurrence interval, or return
period, is the average time span between large earthquakes at a
particular site.
(Image
courtesy Charles Ammon, Penn State)
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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.
Reflection
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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
(Images courtesy of Charles Ammon, Penn State)
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A regression analysis is a statistical
technique applied to data to determine, for predictive purposes,
the degree of correlation of a dependent variable with one or
more independent variables, in other words, to see if there is a
strong or weak cause and effect relationship between to things.
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The residual is the difference between the measured and
predicted values of some quantity.
(Image courtesy of
Curators of the Univ. of Missouri)
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The recurrence interval, or return period, is the average time
span between large earthquakes at a particular site.
(Image courtesy Charles
Ammon, Penn State)
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If you were to stand on the fault and
look along its length, this is a type of strike-slip fault where
the right block moves toward you and the left block moves away.
(Image
courtesy of Steven Dutch, University of Wisconsin)
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The Richter magnitude scale was developed
in 1935 by Charles F. Richter of the California Institute of
Technology as a mathematical device to compare the size of
earthquakes. The magnitude of an earthquake is determined from the
logarithm of the amplitude of waves recorded by seismographs.
Adjustments are included for the variation in the distance between
the various seismographs and the epicenter of the earthquakes. On
the Richter Scale, magnitude is expressed in whole numbers and
decimal fractions. For example, a magnitude 5.3 might be computed
for a moderate earthquake, and a strong earthquake might be rated
as magnitude 6.3. Because of the logarithmic basis of the scale,
each whole number increase in magnitude represents a tenfold
increase in measured amplitude; as an estimate of energy, each
whole number step in the magnitude scale corresponds to the
release of about 31 times more energy than the amount associated
with the preceding whole number value.
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The "Ring of Fire", also called the
Circum-Pacific belt, is the zone of earthquakes surrounding the
Pacific Ocean--about 90% of the world's earthquakes occur there.
The next most seismic region (5-6% of earthquakes) is the Alpide
belt (extends from Mediterranean region, eastward through Turkey,
Iran, and northern India.
From
"This Dynamic Earth: The Story of Plate Tectonics"
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The rupture front is the instantaneous
boundary between the slipping and locked parts of a fault during
an earthquake. Rupture in one direction on the fault is referred
to as unilateral. Rupture may radiate outward in a circular manner
or it may radiate toward the two ends of the fault from an
interior point, behavior referred to as bilateral.
Rupture front
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The speed at which a rupture front moves
across the surface of the fault during an earthquake.
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