Introduction to Introduction to VolcanologyVolcanology

November 2009November 2009

ContentContent1.- Volcano.

Concept. Origin. Parts. Earthquakes, tsunamis and volcanoes. Volcanology.Volcanism.

VolcanoVolcano

An opening in the earth’s surface through which lava, hot gases, and

rock fragments erupt.

Origin of VolcanosOrigin of Volcanos1.- Magma 50-100 miles below the earth’s surface slowly begins to rise to the

surface.

2.- As the magma rises it melts gaps in the surrounding rock.

3.- As more magma rises a large reservoir forms as close as 2 miles below the surface (magma chamber)

4.- Pressure from the surrounding rock causes the magma to blast or melt a conduit (channel) to the surface where magma erupts onto the surface through a vent (opening).

5.- The magma, now called lava, builds up at the vent forming a volcano.

6.- Often the volcano sides will be higher than the vent forming a depression called a crater

VolcanoVolcano

Mount Saint Helen Eruption, May 18th 1980

Magma chamber

conduitmantle

Parasitic Cone

Ash Cloud/Gases

Vent

Lava Flow

Crater

Parts of a VolcanoParts of a Volcano

““Ring of Fire”Ring of Fire”

Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called , a zone of frequent earthquakes and volcanic eruptions.

Volcanoes and earthquakesThe distribution of earthquakes provides information about magma pathways and the structure of volcanoes and they

also can have a lot to do with generating tsunami. Any time that you can somehow displace a large amount of ocean water you generate a large wave or group of waves that

goes rushing across the ocean at great speed.

VolcanologyVolcanology

Volcanology (also spelled vulcanology) is the branch of

geology that studies volcanoes, lava, magma and related geological phenomena.

VolcanismVolcanism

Volcanism is part of the process of bringing material from the deep interior of a planet and spilling it forth on the surface. In many

cases, eruptions build up a piled of material, a

mountain what is called volcano.

Heat SourceHeat Source

The heat from a volcano comes from deep within the earth.

Many miles underground, the earth is hot. Rocks beneath the earth are so hot they turn into

a liquid called lava.

When a volcano erupts, the steam and ash is caused by lava that is forcing its way toward the surface of the

earth.