series of less powerful earthquakes that follow the main quake. aftershocks may continue for days.
south american mountain range with many volcanoes made of andesite lava
lava found on continental volcanoes. it forms very steep-sided volcanoes
rock layers folded by compression. the upfold is known as an anticline and the downfold a syncline.
the upper part of the mantle. this is a partly molten plastic zone in which convection currents are present. plates float on this zone.
a dark colored extrusive igneous rock (lava) usually found in ocean crust. forms sea floors.
a mass of intrusive igneous rock. sometimes covers thousands of square kilometers. if erosion removes overlying layers the batholith will be exposed.
earthquake zone at subduction zone.
a break in rock caused by too much stress
a large volcanic crater created by a violent volocanic explosion or implosion.
the center (core) of the earth. consists of iner and outer layers.
a fossil fuel produced from the compacted and pressurized remains of tropical vegetation.
columns formed when basaltic lava cools and fractures.
type of volcanic mountain. composed of layers of cinders and andesitic lava. pacific ring of fire volcanoes are composite cones.
pressure forcing rock surfaces to be pushed together
the flat shallow ocean floor next to the continent. may stretch out for 100 kilometers or so before deep ocean is reached.
the drop-off from shallow continental shelf to the deep ocean floor.
crater lake, oregon
example of a caldera filled with water
a rock formation that results when magma breaks across rock layers
as rock is subjected to stress for extended time, the rock may become permanently deformed.
violent shaking of the earth's surface caused by a sudden displacement of subsurface rock masses.
rock returns to its original shape after stress is removed
point on the earth's surface directly above the focus.
continent building. continental surfaces have been elevated or depression, with little or no folding.
a fracture in the earth's crust.
a long crack in the earth's crust. lava may occasionally extrude from fissures.
created when earth's crust is compressed and folded. himalayas, alps, rockies, appalachians are examples of fold mountains.
point in the earth's surface where rock fractures, resulting in an earthquake.
oceanic volcanic (igneous) rock with large crystals.
similar to hot spring but a blockage occurs in the fault line. water and steam collect, pressure builds, water and steam are forcefully expelled.
a downshifted block of strata (rock layers) in between two faults. also known as a rift valley.
uplifted block of strata in between two faults. also known as a block mountain.
water heated by magma close to the surface that finds an escape route through cracks in the earth's crust.
rocks formed by the cooling and hardening of magma from within the earth's mantle.
a dome-like pooling of magma that occurs underground between rock layers.
mudflow caused when a volcano's heat rapidly melts ice and snow on slopes of volcano.
literally means 'becoming a liquid'. when some types of soils (sand and silt) are shaken violently in an earthquake, the soil may liquefy and behave much like quicksand. soil strength is lost and buildings can topple or begin to sink.
the solid outer crust of the earth.
when movement at a fault is prevented by excessive friction.
the size of an earthquake
submerged shorelines that support a distinct forest ecosystem adapted to living in seawater.
an igneous or sedimentary rock that has undergone a change by heat or pressure inside the earth's surface.
the layer of the earth directly below the crust. it extends to the outer core. also called the mantle.
location on the ocean floor where plates are diverging. here new land is being created.
mohorovicic discontinuity (moho)
boundary between the lithosphere and the mesosphere.
super heated, denser that air deadly volcanic gases.
a fossil fuel produced from the compaction of minute sea creatures on the sea floor.
a mined mineral.
process of mountain building
alfred wegner's super continent from which today's continents split and drifted to their present locations.
the theory of plate tectonics state that the lithosphere is broken into a series of rigid plates which are propelled along by convection currents in the asthenosphere.
primary or compression wave generated by an earthquake. it travels through the ground by compressing and expanding it.
refers to any material blasted out of a volcano.
measures the severity of earthquakes. each number is 10 times larger than the previous.
example of sedimentary rock.
steep cliff that is result of vertical displacement of rock along a fault line.
small, erdoed particles of rock fragments carried by water, ice, and wind and deposited in low lying areas.
one of three main rock types. created when sediment collects in low-lying areas, is slowly pressurized and compacted into layered rock.
instrument used to detect earthquakes.
a scientist who studies earthquakes.
an example of sedimentary rock
ocean volcanoes with very gentle slopes. composed of basaltic lava.
name given to the continental crust.
a rock formation that occurs when magma intrudes between rock layers, cools, hardens, and may eventually be exposed by erosion.
name given to the continental crust.
where plates move only horizontally past one another. also known as transform or tear fault. creates earthquakes.
a plate boundary where one plate over rides another plate forcing the other to dive down and be reclaimed by the mantle.
a gradual settling of ground. may be caused by over use of ground water or weight of glacial ice.
created when primary and secondary waves generated by an earthquake reach the surface, the result is a surface wave. surface waves travel like ripples on water.
secondary wave or shear wave generated by an earthquake. it travels through the earth in a side to side motion.
rock layers folded by compression. the downfold is known as a syncline
crack in the earth where only horizontal movement of rock occurs. also known as transform fault, strike-slip fault.
process in which rock surfaces are pulled apart.
a boundary where plates slide horizontally past each other with no vertical movement.
deep area of the ocean where two colliding plates pull each other down.
huge wave usually caused by an earthquake on the ocean floor or underwater volcanic eruption.
the rock that is left standing when erosion exposes the hard volcanic rock inside an ancient volcano.