2. 1. What is Volcanic Eruption?
2. Definition of Volcano.
3. The products of Volcanic Eruption.
4. Types of Volcanic Eruption.
5. Types of Volcanoes.
6. Positive effects of Volcanic Eruptions.
7. Negative effects of Volcanic Eruptions.
8. Picture of Before the Volcanic Erupt.
9. Picture of During Volcanic Eruptions.
10. The Picture After the Volcanic Erupt.
Table Of Contents
3. A volcanic eruption occurs when hot materials are thrown out of
a volcano. Lava, rocks, dust, ash and gas compounds are some of
the materials.
Eruptions can come from side branches or from the top of the
volcano. Some eruptions are terrible explosions that throw out
huge amounts of rock and ash and kill many people.
Some are quiet outflows of hot lava. Several more complex types
of volcanic eruptions have been described by volcanologists.
These are often named after famous volcanoes where that type of
eruption has been seen. Some volcanoes may show only one type
of eruption during a period of activity, while others may show a
range of types in a series.
What is Volcanic Eruption?
4. A volcano is a vent or chimney which transfers molten rock
known as magma from depth to the Earth's surface. Magma
erupting from a volcano is called lava and is the material which
builds up the cone surrounding the vent.
A volcano is active if it is erupting lava, releasing gas or
generates seismic activity. A volcano is dormant if it has not
erupted for a long time but could erupt again in the future. Once
a volcano has been dormant for more than 10,000 years, it is
termed extinct.
What is Volcano?
5. The drama of a volcanic eruption transfers materials from inside the Earth to our
planet’s surface. Products of an eruption come in three forms lava flows, pyroclastic
debris, and gas. Note that we use the name flow for both a molten, moving layer of
lava and for the solid layer of rock that forms when the lava freezes.
The products of Volcanic Eruption
6. Hawaiian eruptions
are a type of volcanic eruption, named after the Hawaiian volcano with which this eruptive type
is hallmark. Hawaiian eruptions are the calmest types of volcanic events, characterized by
the effusive eruption of very fluid basalt-type lavas with low gaseous content. The volume of
ejected material from Hawaiian eruptions is less than half of that found in other eruptive types.
Steady production of small amounts of lava builds up the large, broad form of a shield volcano.
Types of Volcanic Eruption
7. Phreatomagmatic eruptions
are volcanic eruptions resulting from interaction between magma and water. They
differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic
eruptions, the products of phreatomagmatic eruptions
contain juvenile (magmatic) clasts. It is common for a large explosive eruption to
have magmatic and phreatomagmatic components.
Type of Volcanoes
8. Phreatic eruption
also called a phreatic explosion, ultravulcanian eruption or steam-blast
eruption,[1] occurs when magma heats ground or surface water. The extreme
temperature of the magma (anywhere from 500 to 1,170 °C (932 to 2,138 °F))
causes near-instantaneous evaporation to steam, resulting in an explosion of
steam, water, ash, rock, and volcanic bombs.
Types of volcanic eruption
9. Volcanoes have done wonderful things for the Earth. They helped cool off the earth removing
heat from its interior. Volcanic emissions have produced the atmosphere and the water of the
oceans. Volcanoes make islands and add to the continents.
Volcanic deposits are also used as building materials. In the 1960’s Robert Bates published
Geology of the Industrial Rocks and Minerals. He noted that basalt and diabase are quarried in the
northeastern and northwest states. Most of the basalt and diabase is used for crushed stone:
concrete aggregate, road metal, railroad ballast, roofing granules, and riprap. High-denisity basalt
and diabase aggregate is used in the concrete shields of nuclear reactors. Some diabase is used for
dimension stone (“black granite”).
Pumice and volcanic ash are used as abrasives, mostly in hand soaps and household cleaners.
The finest grades are used to finish silverware, polish metal parts before electroplating, and for
woodworking. Bates reports that in ancient Rome lime and volcanic ash were mixed to make
cement. In modern times pumice and volcanic ash have been used to make cement for major
construction projects (dams) in California and Oklahoma. Pumice and volcanic ash continue to be
used as lightweight aggregate in concrete, especially precast concrete blocks. Crushed and ground
pumice are also used for loose-fill insulation, filter aids, poultry litter, soil conditioner, sweeping
compound, insecticide carrier, and blacktop highway dressing. Perlite is volcanic glass (made of
rhyolite) that has incorporated 2-5% water. Perlite expands rapidly when heated. Perlite is used
mostly as aggregate in plaster. Some perlite is used as aggregate in concrete, especially in precast
walls. (Bates, R.L., 1969, Geology of the Industrial Rocks and Minerals: Dover, NY,459 p.)
Positive Effects of Volcanic Eruption
12. Listen to the radio for civil defence advice and follow instructions.
If outside at the time of eruption, seek shelter in a car or a building.
If caught in volcanic ashfalls, wear a dust mask or use a handkerchief or
cloth over your nose and mouth.
Stay indoors as volcanic ash is a health hazard, especially if you have
respiratory difficulties such as asthma or bronchitis.
When indoors, close all windows and doors to limit the entry of volcanic
ash. Place damp towels at thresholds.
Do not tie up phone lines with non-emergency calls.
If you have to go outside use protective gear such as masks and goggles
and keep as much of your skin covered as possible. Wear eyeglasses, not
contact lenses as these can cause corneal abrasions.
Disconnect drainpipes/downspouts from gutters to stop drains clogging. If
you use a rainwater collection system for your water supply, disconnect the
tank.
Stay out of designated restricted zones.
During Volcanic Eruption