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. - PowerPoint PPT Presentation
Volcanoes: Natures Awesome Power
Volcanoes: Natures Awesome PowerBy Maryann Dobeck
IntroductionCenturies 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 pEarth is made of four
layers, outer layer is the crust.Geologists believe the crust and
upper mantle are made of 10 huge plates and 6 smaller plates.The
worlds erupting volcanoes occur along edges or boundaries, of
Volcanoes are mountains that are built from eruptions of
volcanic materials onto earths 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
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 earths.
CH.2: Types of volcanoesTheir 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
Cinder conesAs 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
Shield volcanoesShield volcanoes are flat and wide.Most of the
Hawaiian Island are shield volcanoes.Mauna Loa is the worlds
CH.3When 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
CH.4: Famous volcanoes & mountainsWhen 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. HelensThe volcano rumbled with earthquakes.
Mount PinatuboMount Pinatubo erupted in a powerful blast 10
times larger than the eruption of MT. St. Helens.