volcanoes science q3

volcano

a fissure in the earth's crust (or in the surface of some other planet) through which molten lava and gases erupt

dormant volcano

A volcano that has not erupted for a long time, but may erupt again one day. are volcanoes that have no records of volcani activity but are young looking.

inactive volcano

are volcanoes that have not erupted for the last 10,000 years and is not expected to erupt again in the future.

active volcano

are those volcanoes that have had atleast one eruption during the past 10,000 years. is erupting or has shown signs that it may erupt in the near future

vent

The opening through which molten rock and gas leave a volcano

crater

a bowl-shaped opening at the top of a volcano

rift

deep long cracks where earth's plates seperate

hot spots

areas of volcanic activities that result from plumes of hot solid material that have risen from deep inside earths mantle

explosive eruption

Volcanic event that can be created when magma is very thick, and clog up a volcano, stopping gases from erupting, leading to a buildup of pressure. often levels of silica and trapped water vapor are very high, causing the viscosity of the magma to increase dramatically

quiet eruption

occurs when magma flows easily and gently bubbles out, the lava is thin and runny as it oozes out quietly from the vent. This type of magma has a low amount of trapped water vapor and silica, causing a more fluid viscosity and allowing the magma to flow

shield volcano

are large and broad volcano that looks like a shield from above with gently sloping sides built by nonexplosive eruptions of basaltic lava that accumulates in layers.

cinder cone volcano

a steep, cone-shaped hill or small mountain made of volcanic ash, cinders, and bombs piled up around a volcano's opening

composite volcano

volcano built by alternating explosive and quiet eruptions that produce layers of tephra and lava; found mostly where Earth's plates come together and one plate sinks below the other

caldera

The large hole at the top of a volcano formed when the roof of a volcano's magma chamber collapses.

silica

A material found in magma that is formed from the elements oxygen and silicon; it is the primary substance of Earth's crust and mantle.

volcano location

volcanoes form in places that are directly related to the movement of earth's plates

Ring of fire

A major belt of volcanoes that rims the Pacific Ocean.

island arc

A string of islands formed by the volcanoes along a deep-ocean trench

hot spring

A pool formed by groundwater that has risen to the surface after being heated by a nearby body of magma.

summit

highest point; apex

flank

the side of a volcano

volcano bombs

are molten rocks thrown out from a volcano and are atleast 66mm in size

eruption column

these clouds of heated ash and tephra are released from a vent during an explosive volcano eruption

ash cloud

ash falls back down like powdery snow

pyroclastic flow

this type of deadly flow contains fast-moving volcanic matter and hot gas

lahar

when hot volcanic material mixes with water from streams or snow and ice

tephra

if magma is thick and sticky, gases cannot escape easily. pressure builds up until the gases escapes violently and explode. this type of magma blasts up into the air and breaks apart into pieces

viscosity

is the property of the materials’s resistance to flow. the more viscous and thicker the magma is, the greater is its resistance to flow

temperature, chemical composition, amount of dissolved gases it contains 

factors affecting the viscosity of magma