Volcanoes, Earthquakes, Earth's History/Geologic Time Reduced Unit
surface waves
Rayleigh waves and Love waves; slowest but most damaging waves
fault
a break in rock layers where movement causes an earthquake
unconformity
a gap or missing layer in a rock column
Ring of Fire
a region around the Pacific Ocean containing most of Earth's active volcanoes
nonexplosive
a type of eruption that produces lava flows or fountains
Sunset Crater
an example of a cinder cone volcano
Mount Fuji
an example of a composite volcano
Mauna Loa
an example of a shield volcano
seismograph
an instrument that records seismic waves
relative age
an object or event being older or younger than another
geologic time
broken into eons, eras, periods, and epochs
P waves
compression or push/pull waves; fastest seismic waves
pyroclastic flows
dangerous volcanic materials such as volcanic bombs, lapilli, and ash
farther
distance at which an earthquake occurred if there is a large time gap between the P waves and S waves
closer
distance at which an earthquake occurred if there is a small time gap between the P waves and S waves
4.6 billion years
estimated age of Earth and the solar system
fossil
evidence of past life; most commonly preserved in sedimentary rock
tsunami
large powerful wave that forms after an underwater earthquake, volcano or landslide
eon
largest unit of geologic time
solids, liquids, gases
material(s) through which P waves can travel
solids only
material(s) through which S waves can travel
magma
molten rock found underneath Earth's surface
earthquake
movement of the ground caused by the sudden release of energy
index fossil
must come from a species that existed for a short period of time
catastrophism
principle that states geologic events are rare and sudden
uniformitarianism
principle that states geologic processes are slow and gradual
superposition
principle that states that younger rocks lie above older rocks if the layers have not been disturbed
Mercalli Scale
ranks an earthquake based on the damage caused
Richter Scale / Moment Magnitude Scale
ranks an earthquake based on the energy released
S waves
shear or side-to-side waves; can only go through solids
era
shorter than an eon, longer than a period
period
smaller than an era, longer than an epoch
epoch
smallest unit of geologic time
plate boundaries
the location on Earth where most earthquakes occur
correlation
the matching of rock layers from different areas in terms of age
lava
the name for magma that reaches Earth's surface
epicenter
the point on the surface directly above the focus of an earthquake
focus
the point underground where an earthquake occurs
seismogram
the record or tracing of an earthquake's seismic waves
cinder cone
the smallest type of volcano with explosive eruptions
composite volcano
the type of volcano with explosive and nonexplosive eruptions
shield volcano
the type of volcano with very long, gentle slopes and nonexplosive eruptions
seismic waves
the way an earthquake's energy travels through the body and surface of Earth
explosive
type of eruption that produces clouds of ash and debris
