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19 terms

Science Vocabulary For Earthquakes And Volcanoes

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fault
surface along which rocks move when they pass their elastic limit and break
earthquake
vibrations produced when rocks break along a fault
normal fault
break in rock caused by tension forces, where rock above the fault surface moves down relative to the rock below the fault surface
reverse fault
break in rock caused by compression forces, where rock above the fault surface moves upward relative to the rock below the fault surface
strike-slip fault
break in rock caused by shear forces, where rocks move past each other without much vertical movement
seismic wave
wave generated by an earthquake
focus
in an earthquake, the point below Earth's surface where energy is released in the form of seismic waves
epicenter
point on Earth's surface directly above an earthquake's focus
seismograph
instrument used to register earthquake waves and record the time that each arrived
volcano
opening in Earth's surface that erupts sulfurous gases, ash, and lava; can form at Earth's plate boundaries, where plates move apart or together, and at hot spots
crater
steep-walled depression around a volcano's vent
vent
opening where magma is forced up and flows out onto Earth's surface as lava, forming a volcano
hot spot
the result of an unusually hot area at the boundary between Earth's mantle and core that forms volcanoes when melted rock is forced upward and breaks through the crust
batholith
largest intrusive igneous rock body that forms when magma being forced upward toward Earth's crust cools slowly and solidifies underground
dike
igneous rock feature formed when magma is squeezed into a vertical crack that cuts across rock layers and hardens underground
sill
igneous rock feature formed when magma is squeezed into a horizontal crack between layers of rock and hardens underground
volcanic neck
solid igneous core of a volcano left behind after the softer cone has been eroded
caldera
large, circular-shaped opening formed when the top of a volcano collapses
laccolith
dome shaped igneous intrusion that is smaller than a batholith