Download - Volcanoes: Nature’s Awesome Power
Volcanoes: Nature’s Awesome Power
By Maryann Dobeck
Introduction• Centuries ago, native people of
Hawaii witnessed volcanic eruptions. • A Hawaiian myth is that a
goddess of volcanoes made mountains blow their tops.• Scientists know that forces of
nature are the cause of volcanic eruptions.
CH.1: The inside story of volcanoes p• Earth is made of four layers,
outer layer is the crust.• Geologist’s believe the crust and
upper mantle are made of 10 huge plates and 6 smaller plates.• The world’s erupting volcanoes
occur along edges or boundaries, of earth’s plates
• Volcanoes are mountains that are built from eruptions of volcanic materials onto earth’s surface.• When pressure on the magma
subsides, the eruption stops.• Three kinds of materials may
erupt from a volcano: lava, tephra (rock fragments), and gases.
• The pressure of the gas in the magma causes the eruption.• A volcano erupts, it can spew
out anything from fine particles of dust to huge block of rock as big as a house.• If magma contains a lot of gas, it
will burst out violently with rock fragments called pyroclastic materials.
Volcanoes on ocean floor/Volcanoes at hot spot• Tectonic plates on the ocean
floor are thinner than plates on land.• In 1963, a volcano formed a new
island called Surtsey.• The largest volcanoes are above
hot spots, areas of superhot rock deep in earth’s.
CH.2: Types of volcanoes• Their are three common types of
volcanoes: stratovolcano, cinder cone volcano, and shield volcano.• Geologist classify volcanoes
based on their size, shape, and formation.• Stratovolcanoes usually have
steep sides and a broad base.
Cinder cones• As lava explodes from the
central vent it breaks into small pieces that fall as cinders around the opening.• Paricutin volcano in Mexico is
one the most famous cinder cone volcanoes.• This volcano usually starts out
small but they quickly build up into a large volcano.
Shield volcanoes• Shield volcanoes are flat and
wide.• Most of the Hawaiian Island are
shield volcanoes.• Mauna Loa is the worlds largest
Volcano.
CH.3• When volcanoes erupt geologists
call the most explosive volcanic eruption a Paleean eruption .• Scientists call the least violent
kind of eruption a Hawaiian eruption.• Lava streams out of several vents
and forms a shield volcano.
• 1 of the worlds most DANGEROUS volcano.
CH.4: Famous volcanoes & mountains• When mount Vesuvius erupted,
ash and lava buried the towns of Pompeii, Herculaneum ,and Stabiae, Krakatoa.• No one lived on Krakatoa, so no
one died.
Mount ST. Helens• The volcano rumbled with
earthquakes.
Mount Pinatubo• Mount Pinatubo erupted in a
powerful blast 10 times larger than the eruption of MT. St. Helens.