Earthquakes Flashcards
seismology
the study of earthquakes
deformation
the bending, tilting, and breaking of the Earth’s crust; the change in shape of rock in response to stress
elastic rebound
the sudden return of elastically deformed rock to its undeformed shape
seismic waves
waves of energy that travel through the Earth, away from an earthquake in all directions
P-waves
a seismic wave that causes particles of a rock to move in a back and forth direction, fastest, through liquid and solid (body wave)
S-waves
a seismic wave that causes particles of a rock to move in a side-to-side direction, through the Earth (only solid), slower wave
seismographs
an instrument that records vibrations in the ground and determines the location and strength of an earthquake
seismogram
a tracing of earthquake motion that is created by a seismograph
epicenter
the point on Earth’s surface directly above an earthquake’s starting point or focus
focus
the point along a fault at which the first motion of an earthquake occurs
magnitude
the measure of the strength of an earthquake
Richter Magnitude Scale
measures the strength of earthquakes
intensity
a measure of the degree to which an earthquake is felt by people and the amount of damage caused by the earthquake
Modified Mercalli Intensity
used to measure earthquake intensity
where are earthquakes common?
along plate boundaries and faults
what is a fault?
a break in the Earth’s crust where the plates shift
surface wave
travels on surface of the Earth
body wave
travels through the Earth
lag time
difference in arrival time of P and S waves
why could volcanoes be creative and destructive
they create land but they destroy surrounding areas
how do water/gas and silica influence eruptions
more of either of them makes the magma more explosive
shield volcano
runny lava, quiet eruptions (biggest type of volcano)
composite volcano
explosive eruptions, lava + pyroclastic material
cinder cone volcano
mildly explosive
dormant volcanoes
not currently active but could become restless and erupt again
active volcanoes
has erupted in historic time, continuous or periodic eruptions
extinct volcanoes
has not erupted in historic time (unlikely to erupt again)
how are lava plateaus formed
lava spread repeatedly over a large area
how are calderas formed
by the collapse of the magma chamber
L (love) waves
travels on surface of the Earth, slowest and most destructive waves, up down and around motion
