What is volcanoes, their types(based on Magma & Based on Eruption style), location, eruption style and different types of rock found nearby the volcanoes. Different tectonic plates, Tectonic Plates movement. Advantages and Disadvantages of volcano.

1. VOLCANOES
SUBMITTED BY:-
HIJAM SANJEEV
2018MSES011

2. INTRODUCTION
 WHAT IS A VOLCANO?
 A volcano is an opening on the surface of a planet or moon that allows
material warmer than its surroundings to escape from its interior. When
this material escapes, it causes an eruption. An eruption can be
explosive, sending material high into the sky. Or it can be calmer, with
gentle flows of material.
 Due to this eruption and material depositing it sometimes form mountain
or hills.
 Volcanoes can be active, dormant or extinct.

4. THIS PHOTOGRAPH SHOWS AN ERUPTION OF MOUNT ST.
HELENS IN WASHINGTON IN JULY 1980. THIS ERUPTION
SENT ASH 6 TO 11 MILES (10-18 KILOMETRES) INTO THE
AIR, AND WAS VISIBLE IN SEATTLE, WASHINGTON, 100
MILES (160 KILOMETRES) TO THE NORTH. CREDIT: MIKE
DOUKAS, USGS

5.  WHAT CAUSES VOLCANOES?
 When materials warmer than the surrounding is erupted
onto the surface.
 When tectonic plates moves apart or moves toward each
other there is chance of formation of volcanoes.
 Due to hot spots area inside Earth surface.
 formation of volcanoes can take place at subduction
zone also.

7. VOLCANOES LOCATION
 Approximately 1500 volcanoes around the
world are considered active, and from these,
nearly 90% lie in the Ring of Fire, which is a
ring of oceanic volcanoes circling the Pacific
Ocean.

9. TYPES OF VOLCANOES
 DEPENDING ON MAGMA TYPE
1. MAFIC OR BASALTIC LAVA
2. INTERMEDIATE OR ANDESITIC
3. FELSIC OR RHYOLITIC

10. ERUPTION STYLE
 CENTRAL ERUPTION
 FISSURE ERUPTION
Central eruption:- Central eruptions discharge lava or
pyroclastic materials from a central vent. The vent is an
opening atop a pipelike feeder channel rising from the
magma chamber.

11. TYPE OF VOLCANOES
 DEPENDING ON ERUPTION TYPES AND
LANDFORMS
1. SHIELD VOLCANOES(eg. Mauna Loa)
2. COMPOSITE OR STRATO VOLCANOES(eg.
Fujiyama in Japan)
3. HOTSPOT
4. CINDER CONE
5. LAVA DOME(eg. Mount st. Helen)
6. CRATER
7. CALDERAS

14. PYROCLASTIC DEPOSIT DUE TO CENTRAL
ERUPTION
 Presence of water and air causes this deposit.
 They burst out with high pressure breaking the
rocks in different shapes, sizes and texture.
 Less than 2mm volcanic ash
 Lava getting solidified in air volcanic bomb
 Pyroclast fall on earth and get lithified.
 Small fragment volcanic tuffs
 Large fragmentvolcanic breccias
 Pyroclastic flow when the ash, lava, got mix
up and start flowing downhill

15. FISSURE ERUPTION
 Eruption due to vertical cracks on earth
surface.
 It is very wide.
 Mainly occurs in newly formed oceanic crust
 It create igneous rock intrusion called dike.

16. FLOOD BASALT
COLUMBIAN RIVER FLOOD BASALT
 Basaltic lava spread out as thin sheet as a flood of lava.
 Covers upto hundreds of kilometers.

17. ASH FLOW DEPOSIT
 Pyroclastic deposit from the fissure eruption.
 Can be seen in Yellowstone National Park,
USA.
 Produce extensive layer of volcanic tuffs.
 Destroy succession in the area.

18. ADVANTAGES OF VOLCANOES
 Fertile soil when lava weathers e.g. Indonesia
 Tourist attractions e.g. Yellowstone National
Park, USA
 Minerals e.g. sulphur
 Hot springs for bathing e.g. Iceland
 Heat used to generate electricity e.g.
geothermal power (Iceland)
 Mud used for skin care
 New land e.g. Surtsey (Iceland)

19. DISADVANTAGES OF VOLCANOES
 Dangerous gases
 Loss of homes, animals and crops
 Diseases and Fires
 Avalanches, mudflows (lahars) and floods
 Loss of wildlife, trees and plants
 People live in fear