Interior of the Earth Short and Long Important Question Class 11 Geography Chapter-3 Book-Fundamental of Physical Geography

 

 

Question – Define earthquake and describe its effects?

Answer - 

• Earthquake means shaking of the ground or movement of the earth.

• The vibration of the earth that starts with a sudden shock is called earthquake.

• it is a natural disaster

The following are the impacts of earthquake disaster

• Ground shaking 

• Surface anomaly 

• Landslide 

• Soil liquefaction 

• Surface displacement 

• Avalanche

• Dam and embankment breaches cause increased risk 

• starting a fire 

• Demolition of buildings 

• Generation of Sumani Waves 

• falling of objects 

• tilt of the ground to one side

Question -  What is a volcano? And describe the types of volcanoes.

Answer - 

• Volcano is a sudden phenomenon that occurs on Earth.

• This causes a sudden explosion on the Earth's surface, due to which love gas, smoke, pebbles, stones etc. come out.

• All these things are released through a natural pipe which is called the exhaust pipe 

• The lava creates a hole in the surface called a crater 

Types of volcanoes: 

• Shield Volcano 

• Mixed volcano 

• Volcanic basin 

• Basalt flow field 

• Mid-ocean ridge volcanism 

1. Shield volcano

• The largest volcanoes are.

• They are made of basalt, where liquid lava cools down to form a shield shape.

• Contains less explosives.

• The lava forms cones called cinder cones.

2. Mixed volcano

• They erupt lavas that are cooler and thicker than basalt.

• Often extremely explosive.

• Volcanic ash and other materials accumulate in layers.

3. Caldera

• The most explosive volcano.

• After the explosion the structure sinks into a depression, called a trough.

4. Basalt flow field

• The most explosive volcano.

• After the explosion the structure sinks into a depression, called a trough.

5. Mid-ocean ridge volcanoes

• They are located in the middle of the oceans.

• 70,000 km. They are spread over a long chain.

• Continuous lava flows

Question:  How many types of seismic waves are there?

Answer -

seismic waves 

1. Geological waves 

• P waves are  primary waves 

• S waves  II waves 

Geological Waves : 

• These waves emerge from the center of origin in the core of the earth and go in different directions. These waves react with surface rocks and turn into surface waves. 

1. Primary waves

• These are the fastest moving waves and are the first to reach the surface.

• These are also called P waves.

• These gases can pass through liquids and solids.

2. Secondary waves

• The secondary waves reach the surface after some time interval.

• These are called ऽ waves.

• These move only through solid substances.'

2. Surface waves

• Due to the interaction between seismic waves and surface rocks, new waves are generated which are called surface waves.

Question:   Briefly explain the internal structure of the Earth?

Answer - 

The internal structure of the Earth is mainly divided into three layers: 

1. Earth's crust 

• It is the outermost part of the Earth. 

• This is a very brittle part and has the tendency to break easily. 

• The thickness varies beneath the continents and oceans. 

• The thickness in the oceans is less than that of the continents. 

• Its thickness in the oceans is 5 km

• It is up to 30 km beneath the continents. 

2. Mental 

• The part below the crust is called the mantle. 

• The upper part of the mantle is called the asthenosphere. 

• Its extension has been estimated to be 400 km. 

• It is in solid state.

3. Core

• The outer core is in liquid state while the inner core is in solid state. 

• The core is made of heavy materials, mainly nickel and iron. 

• It is also known as 'Nife' layer.

Question -   What are the Plutonic rocks? Describe the major intrusive shapes

Answer -

1. Plutonic rocks: 

• When the lava cools and solidifies beneath the surface. 

• When lava cools within the Earth's crust, many shapes are formed. 

• These shapes are called intrusive forms.

Interpenetrating shapes  

1. Batholith

• When a large body of magma cools at greater depths in the Earth's crust, it develops into a dome shape.

• These are spread over a vast area and sometimes their depth can be up to several kilometers.

2. Laccolith

• These are huge dome-shaped intrusive rocks whose surface is flat and connected to a pipe-like carrier tube from below.

3. Lapolith

• Some part of the rising lava moves into the weak surface found in the horizontal direction.

• If it solidifies in the shape of a saucer then it is called lapolith.

4. Faecolith

• Sometimes, deposits of lava are found at the top of the anticline and at the bottom of the syncline in the folded state of intrusive igneous rocks. 

• These sedimentary/wavy rocks are connected to the magma reservoirs by a certain convector tube. 

• This is called faecolith.

5. Seal

• The lava that cools in the form of a sheet in the horizontal plane is called a sill or sheet. 

• These are divided based on the thickness of the deposits-depositions with less thickness are called sheets and deposits with dense thickness are called sills. 

6. Dyke

• When the flow of lava in the cracks is almost at a right angle to the surface and if it cools down in this condition, it forms a structure like a wall. This structure is called a dyke.