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Following are the effects of earthquakes:

• Cracks/fractures develop on the ground. 
• These causes landslides which leads to sliding of rocks.
• Sometimes the groundwater changes its course. For example, wells may get water, or may dry up. Some areas get uplifted while some may subside. 
• Tsunamis are generated in oceans These waves can cause great loss of life and property in the coastal areas. 
• In snow-covered areas, avalanches may occur.
• Buildings collapse and loss of life and property occurs. 
• Transportation routes get disrupted. 
• The communication system collapses.

• Through a seismogram, a graph showing movement of seismic waves (seismograph) can be generated.
• After studying this graph, the magnitude of the earthquake is known. 
• The magnitude of the earthquake is measured with the help of a richter scale. 
• It is because of the primary waves that the buildings on the Earth’s surface move back and forth. 
• The buildings on the Earth’s surface move up and down because of the secondary waves. These are more destructive than the T’ waves leading to collapse of buildings.

• Fold mountains are formed due to mountainbuilding (erogenic) movements. 
• Energy is transferred from the interior of the Earth. Because of these energy waves and pressure working towards each other and in horizontal direction, the layers of the soft rocks form folds. 
• If the pressure is very high, large scale folds are formed and their complexity increases. 
• As a result, the surface of the Earth gets uplifted and fold mountains are formed. 
• The Himalayas, the Aravalis, the Rockies, the Andes, the Alps are the major fold mountains of the world.

Correct option is (b) orogenic

Correct option is (a) plates

Correct option is (c) earthquake

The earthquake waves that reach the surface of the Earth first, immediately after the energy is released in the interior of the Earth, are called Primary waves.

It is a scale for expressing the magnitude of an earthquake.

Endogenetic processes are processes that originate internally in the Earth’s surface. E.g. earthquakes, volcanoes, continent building, mountain building etc.

An instrument, which is used for recording earthquakes is Seismogram

Correct option is (a) Black forest mountain

Correct option is (b) sudden

Correct option is (b) The Himalayas 

According to the periodicity of the volcanic eruptions, three types of volcanoes can be identified. 

(i) Active Volcanoes –

• If the volcanic eruptions are regular even in the present times, then such volcanoes are called active volcanoes. 
• E.g., Mt Fujiyama in Japan and Mt. Stromboli in the Mediterranean Sea.

(ii) Dormant Volcanoes –

• When a volcano has not erupted since long, but may become active suddenly is called a dormant volcano. 
• E.g., Mt. Vesuvius in Italy, Mt. Katmai in Alaska and Barren Island, India.

(iii) Extinct volcanoes –

• Those volcanoes which have not erupted in the past since long and are not likely to erupt in the future are called extinct volcanoes. 
• E.g., Mr. Kilimanjaro in Tanzania.

Mt. Kilimanjaro

Deccan Plateau.

The slow movements in the interior of the Earth that give rise to mountains are called orogenic movements (mountain building movements).

As energy moves through the interior of the Earth, soft rocks are subjected to pressure leading to creation of folds called folding.

Sudden Movement

A process in which hot solid, liquid and gaseous materials are thrown out from the mantle of the earth onto the surface of the earth, is called volcanic eruption.

The Earth’s slow movements that give rise to continents and extensive plateaus are called epeirogenic movements.

A raised portion of the crust between two parallel faults is called a block mountain.

The fracture line created in a rock due to the energy waves moving away from each other is called a fault.

• Due to secondary earthquake waves, the grains in the rocks move up and down, that is, perpendicular to the direction of the movement of the waves. 
• Therefore, secondary waves are very destructive.

(i) North American Plate, South American Plate, Indo Australian Plate, African Plate, Eurasian Plate, Pacific Plate, Antarctic Plate, Arabian Plate, Nazca Plate, Cocos Plate, Caribbean Plate, Scotia Plate, Arabian Plate and Somali Plate.

(ii) The earthquake-prone zone is located on the western side of North and South America. Rockies and Andes mountain ranges are located there.

(iii) The Himalayan mountainous zone of Asia is an earthquake-prone zone.

(iv) Volcanoes are concentrated in the eastern part of Africa along the Rift Valley region as this region is located on plate boundaries.

(v) Plate boundaries are directly related to areas of earthquakes and volcanoes. Most of the volcanoes are located on the plate boundaries. Similarly, the earthquake zones are also seen in the border areas.

Correct option is (a) rift valley