Most people have never seen a real volcano but have

learned about them through movies or books.

So when most people think of a volcano, they usually conjure

up the Hollywood version: a huge,

menacing conical mountain that explodes and spews out

masses of lava which falls on rampaging

dinosaurs, screaming cave people, or fleeing mobs of

betogaed Romans - depending on their favorite

volcano disaster movie. While those types of volcanoes do

indeed exist, they represent only one

"species" in a veritable zoo of volcano shapes and sizes.

introduction

types of Volcano

• Fissure

Volcanoes

• Composite

Volcanoes

• Shield Volcanoes

• Cinder cones

Volcanoes

• Lava domes

Volcanoes

• Supervolcano

• Submarine

Volcanoes

Fissure volcanoes have no central crater at all.

Instead,

giant cracks open in the ground and expel vast quantities

of lava. This lava spreads far and wide to form huge pools

that can cover almost everything around. When these

pools of lava cool and solidify, the surface remains mostly

flat. Since the source cracks are usually buried, there is

often nothing "volcano-like" to see - only a flat plain.

A fissure eruption occurred at the Los Pilas volcano

in Nicaragua in 1952.

Fissure VOLCANOES

Fissure VOLCANOES

COMPOSITE VOLCANOES

The most majestic of the volcanoes are

composite volcanoes, also known as strato-volcanoes.

Composite volcanoes are tall, symetrically shaped,

with steep sides, sometimes rising 10,000 feet high.

They are built of alternating layers of lava flows,

volcanic ash, and cinders.

Famous composite volcanoes include Mount

Fuji in Japan, Mount Shasta and Mount Lassen in

California, Mount St. Helens and Mount Rainier in

Washington State, Mount Hood in Oregon, and Mount

Etna in Italy.

COMPOSITE VOLCANOES

Shield volcanoes can grow to be very big. In fact,

the oldest continental regions of Earth may be the remains

of ancient shield volcanoes.

Shield volcanoes are tall and broad with flat,

rounded shapes. They have low slopes and almost always

have large craters at their summits. The Hawaiian

volcanoes exemplify the common type of shield volcano.

They are built by countless outpourings of lava that

advance great distances from a central summit vent or

group of vents.

SHIELD VOLCANOES

SHIELD VOLCANOES

The outpourings of lava are typically not

accompanied by pyroclastic material, which make the

shield volcanoes relatively safe during eruptions.

Mauna Loa, a shield volcano on the "big" island of

Hawaii, is the largest single mountain in the world, rising

over 30,000 feet above the ocean floor and reaching

almost 100 miles across at its base. Other famous shield

volcanoes include Kilauea, also in Hawaii, and Olympus

Mons of Mars.

SHIELD VOLCANOES

Cinder cones VOLCANOES

Cinder cones are simple volcanoes which have a

bowl-shaped crater at the summit and steep sides. They

only grow to about a thousand feet, the size of a hill.

They usually are created of eruptions from a single

opening, unlike a strato-volcano or shield volcano which

can erupt from many different openings. Cinder cones

are typically are made of piles of lava, not ash. A cinder

cone or scoria cone is a steep conical hill of tephra

(volcanic debris) that accumulates around and

downwind from a volcanic vent .

They consist of loose pyroclastic debris formed by

explosive eruptions or lava fountains from a single,

typically cylindrical, vent. As the gas-charged lava is

blown violently into the air, it breaks into small

fragments that solidify and fall as either cinders,

clinkers, or scoria around the vent to form a cone that

often is beautifully symmetrical; with slopes between

30-40°; and a nearly circular ground

Cinder cones VOLCANOES

Cinder cones VOLCANOES

plan. Most cinder cones have a bowl-

shaped crater at the summit. During the eruption,

blobs ("cinders") of lava are blown into the air and

break into small fragments that fall around the

opening of the volcano. The pile forms an oval-

shaped small volcano.

Famous cinder cones include Paricutin in

Mexico and the one in the middle of Crater Lake in

Oregon

Cinder cones VOLCANOES

Volcanic or lava domes are formed by relatively

small, bulbous masses of lava too viscous to flow any

great distance; consequently, on extrusion, the lava piles

over and around its vent. A dome grows largely by

expansion from within. As it grows its outer surface cools

and hardens, then shatters, spilling loose fragments down

its sides. Some domes form craggy knobs or spines over

the volcanic vent, whereas others form short, steep-sided

lava flows known as “coulees.”

Volcanic domes commonly occur within the craters

or on the flanks of large composite volcanoes.

Lava domesVOLCANOES

Lava domesVOLCANOES

A supervolcano usually has a large caldera and

can produce devastation on an enormous, sometimes

continental, scale. Such volcanoes are able to severely

cool global temperatures for many years after the

eruption due to the huge volumes of sulfur and ash

released into the atmosphere. They are the most

dangerous type of volcano. Examples

include: Yellowstone Caldera in Yellowstone

National and Valles Caldera in New Mexico (both

western United States);

superVOLCANO

Lake Taupo in New Zealand; Lake Toba in Sumatra,

Indonesia; Ngorongoro Crater in Tanzania;

and Krakatoa near Java and Sumatra, Indonesia.

Because of the enormous area they may cover,

supervolcanoes are hard to identify centuries after an

eruption. Similarly, large igneous provinces are also

considered supervolcanoes because of the vast

amount of basalt lava erupted (even though the lava

flow is non-explosive).

superVOLCANO

superVOLCANO

Submarine volcanoes are common features of the

ocean floor. In shallow water, active volcanoes disclose

their presence by blasting steam and rocky debris high

above the ocean's surface. In the ocean's deep, the

tremendous weight of the water above prevents the

explosive release of steam and gases; however, they can

be detected by hydrophones and discoloration of water

because of volcanic gases . Pillow lava is a common

eruptive product of submarine volcanoes and is

characterized by thick sequences of discontinuous pillow-

shaped masses which form under water.

submarineVOLCANO

Even large submarine eruptions may not disturb the

ocean surface due to the rapid cooling effect and

increased buoyancy of water (as compared to air)

which often causes volcanic vents to form steep pillars

on the ocean floor . Hydrothermal vents are common

near these volcanoes, and some support peculiar

ecosystems based on dissolved minerals. Over time,

the formations created by submarine volcanoes may

become so large that they break the ocean surface as

new islands or floating pumice rafts .

submarineVOLCANO

submarineVOLCANO

questions:

1. _________ cones are simple volcanoes which

have a bowl-shaped crater at the summit and steep

sides.2. _________ volcanoes are tall, symmetrically

shaped, with steep sides, sometimes rising 10,000

feet high. 3. A ___________ usually has a

large caldera and can produce devastation on

an enormous, sometimes continental, scale.

questions:

6. _________ volcanoes have no central crater at

all.

4. _________ volcanoes are tall and broad with

flat, rounded shapes.

5. _________ volcanoes are common features of the

ocean floor.

7. __________ commonly occur within the craters

or on the flanks of large composite volcanoes.

SUBMITTED BY

: FERRERA, RUTH C.

: DORIMAN, CHERRELYN A.

SUBMITTED TO

: MRS. NORA

PEDROSO