Volcanism

Question 1

Volcanism diagram

Answer 1

Label too

Question 2

Type of lava in volcano

Answer 2

Andesitic or stratovalcano lava or acidic lava

Basaltic or basic lava

Question 3

Andesitic lava

Viscosity, silica content, convergence or divergence boundary?

Answer 3

highly viscous flow slowly
high percentage of silica.
along the destructive boundaries (convergent boundaries).

Question 4

Basaltic lava
Who’s hotter? Andesite or basalt?
Viscosity and flow?
Poor in? And rich in?
Type of eruption 
Which boundary?

Answer 4

hottest lavas
highly fluid
poor in silica
Dark coloured basalt, rich in iron and magnesium
quiet eruption
constructive boundaries (divergent boundary)

Question 5

6 Intrusive volcanic landforms? And shape

Answer 5

Batholith = base
Laccoliths = dome-shaped(Karnataka plateau)
Sills= horizontal bodies of intrusive igneous rocks
Dykes= lava makes its way through cracks and gets cooled in the same position, perpendicular to develop a wall-like structure. Such structures are called dykes.
Lupe= u shaped
Phaco = wave like

Question 6

7-8 types of extrusive volcanic landforms.

Answer 6

Shield
Composite cone
Fissure Type Flood Basalt 
Crater
Caldera
Cinder cone
Fumaroles 
Lava Dome

Question 7

Fumarole

Answer 7

when source of lava dies, last sign of active volcano . Sulluru is most important

Question 8

Lava Dome

Answer 8

viscous magma piles up around the vent.

Question 9

Cinder cone

Answer 9

steep circular or oval-shaped hill of loose pyroclastic fragments that have been built around a volcanic vent.

Question 10

Calder and caldera lake or crater lake.

Answer 10

The volcanic material above the chamber collapses into the empty magma chamber

water from rain or melted snow gets accumulated in the caldera, it becomes a caldera lake and if crater then crater lake.

Lake Toba (Indonesia) formed after its supervolcanic eruption around 75,000 years ago. It is the largest crater lake in the world.

Crater lake could be both volcanic and meteor.

Question 11

Crater

Answer 11

After extinction, the mouth’s depression is called crater.

When water is filled, it is crater lake.

Question 12

Shield Type

Answer 12

Hawaiian volcanoes are most familiar like the mauna kea(dormant) and mauna loa(active)
Basaltic

Question 13

Hotspot volcanism occurs due to?

Answer 13

Hotspot volcanism occurs due to abnormally hot centres in the mantle known as mantle plume

Question 14

mantle plume

Answer 14

convection of abnormally hot rock (magma) within the Earth’s mantle

Question 15

Where is mantle plume found?

Answer 15

position of the mantle plumes seems to be relatively fixed.

• Mantle plumes are theorised to form at the core-mantle boundary

Question 16

Reunion hotspot is an example of basaltic or andesitic activities?

Answer 16

basaltic.

As, produced the Deccan Traps about 66 million years ago)

Question 17

Mantle plumes and volcanic hotspots

Answer 17

The mantle plume provides a continuous supply of abnormally hot magma to a fixed location in the mantle referred to as a hotspot.

Question 18

Name few hotspot volcanic chain?

Answer 18

Hawaiian Islands chain

Réunion: the Chagos- Laccadive Ridge and mascarene plateau are its volcanic traces.

Yellowstone: coz of mantle plume and thinning of continental crust

Question 19

Region of Pacific ring of fire

Answer 19

• The Aleutian Islands into Kamchatka, Japan,
• the Philippines, and Indonesia (Java and Sumatra in particular),
• Pacific islands of Solomon, New Zealand.
• Andes to Central America, Mexico and right up to
Alaska.

Question 20

Mount Vesuvius

Answer 20

stratovolcano in Bay of Naples, Italy.

79 AD that buried the Roman town of Pompeii.

Question 21

Stromboli Volcano

Answer 21

(lighthouse of the Mediterranean

erupting continuously for centuries

Question 22

Krakatoa

Answer 22

Krakatoa (Krakatau or Krakatoa Archipelago) is a group of four small volcanic islands in the Sunda Strait, between Java and Sumatra.