• Hot spot volcano on continental crust

• Cracks on continental crust –Basaltic eruption

• Spread across the land • Layer over layer• EX. Deccan lava trapps

Lava plateaus

• Indian plate passed over a hot spot near Reunion Island

• Basaltic eruption• Layer over layers – looks

like steps => Deccan lava traps

• Soil – black soil ‘regur’

Indian Deccan trap

Spatial distribution of Lava Plateau

• Columbia-snake plateau, USA

• Ozark plateau, USA• Parana-Patagonia, S.

America• Adamawa plateau,

Africa• Bie plateau, Africa• Katanga Plateau, Africa

Deccan plateau, India• Arabian plateau• Balkan plateau, Europe• Siberian plateau, Russia• Yunan Plateau, China• Shan plateau, Myanmar• Kimberly plateau,

Australia

List of lava plateaus of the world

Extrusive

Volcanic Plateau

Volcanic cones

Shield volcano

Cinder vol.

Composite vol.

Extrusive volcanic Landforms

• Volcanic Islands (Hot spot)• Highly fluid lava

(basaltic) build dome • Gentle slope• Quite volcano• Volcanoes of Hawaii

Shield / Dome volcano

• O-C collision – volcanic mountains

• Less fluid lava (Andesitic) explode violently

• Viscous lava solidifies at short distance

• Mt. Paricutin, Mexico

Cinder cones

Volcanic mountainsEach new eruption – new layers of ash or lava

Mt. Stromboli, Mt. Vesuvius, Mt. Fuji

Composite Cones

Shield/ dome Cinder Composite

Highly fluid Less fluid / highly viscous

Fluid + viscous

Silent flow Violent eruption

Multiple and violent eruption

Gentle slope Steep slope Highest volcanoes

Small volcanoes

Small volcanoes

Large volcanoes

Types of Volcanic cones

• Geysers =fountains of Hot water

• Ground water heated by shallow source of magma

• Old faithful geyser, Yellow stone park, USA

Geysers

• Hot Spring: • Water reach deep

enough – heated by interior

• Locate any part of the world

Hot Spring

• Geyser – G/w heated by shallow magma source

• Hot spring – g/w heated by either magma source or heated rocks

• Geyser – chamber in interior – pressure – comes out like fountain

• Hot –spring - quite

Difference between geyser and Hotspring

geyser• Geysers are rare• Hot water dissolved with

silica accumulated on surface – gives different colours

• USA, - Yellowstone park

• Found anywhere• They gets different colors

from heat-loving bacteria, like cyanobacteria

• Medicinal values• Can be helpful in harness

geo-thermal energy

Hot spring

comparison

• Heated water is taken out – used for moving turbine – generation of electricity

• Cooled water flown back into interior

Geo-thermal energy

• Difficult to locate a good source of geothermal reservoir with current technology

• Difficult to dig a deep well with hard and hot bedrock

• Harmful gases can escape from the earth interior while exploration – GHG gases and dissolved toxic elements

Limitations of geo-thermal energy

volcanism

earthquake

Tsunami

Sudden movement or vibration in earth’s crust.

Release of the energy due to intense pressure + active internal dynamism of the earth

Earthquake

Geomorpho

1) Shallow focus EQ2) Intermediate focus EQ3) Deep focus EQ

Shallow focus – destructive

Types of Earthquake

At Junction of 3 plates Subduction of Pacific plate

Earthquakes in Japan

1st Collision of Plate boundariesO-O collisionO-C collisionC-C collision

Reasons behind EQ

2nd

Divergent Plate boundaries

O-O divergence MOR

Reasons behind EQ

• 3th• Transverse plate

boundaries• Friction developed

between two plates

Reasons behind EQ

4th Mediterranean sea regionNumerous small platesFrequent interactions

Reasons behind EQ

5th Craton = stable part of crustRe-emergence of old fractures

6th Human Induced 1) RIS2) mining3) Nuclear testing

Reasons behind EQ

Catastrophic events on earth

Their reasons and distributions

VolcanismEQ

Geomorphology

Oceanography

volcanism

earthquake

Tsunami

Submarine EQSudden disturbances of underlying plates transmit the shock waves to surface waves

Tsunami

Geomorpho

Normal wavesSpeed – 100 kmphCover shorter distancesWavelength ~100 km

• Speed – 700 kmph• Cover longer distances• Wavelength – > 150 km

Tsunami waves

comparison

• Distance between two crests of troughs = wavelength

• Waves of Tsunami are wider than normal waves of the ocean water

wavelength

• EQ on ocean crust – uplift the water upward

• Tsunami wave generated

• Sea water recede at the shore

• Vessels in the mid-sea cannot recongnise the tsunami waves

Phase 1

• At coast – depth decrease – wavelength decreases – wave height increases

• A huge wall of water – 10-12 floor high created

• Enormous energy released at the shore

Phase 2

• Hit the coast• Tsunami- not a single

wave but multiple waves

• 4th and 8th waves are the most dangerous

• Time lapse between each waves – 15 to 50 minutes

Phase 3

Phases of tsunami

• Tsunami Early warning system- gives warning in 10 minutes of submarine earthquake

• Indian National centre for Ocean Information Sciences (INCOIS),Hyderabad

• To capture Tsunami wave amplitude on 24x7 basis• real time sea-level sensors with bottom pressure

recorders• HF radars for coastal currents• Coastal tide gauge stations

Indian preparedness against Tsunami

GeomorphologyInterior of the earthContinental drift – sea floor sprading- plate tectonic theories

Mountains –plateaus –plains

Catastrophic events – Volcanism, EQ and Tsunami