ICSE Class 9 Answered

Extrusive landforms that are formed due to the eruption of volcanoes are:

• Conical hill: A cone shaped hill is a typical example of an extrusive landform.

   

• Cone: A cone is formed when rock materials and debris are thrown away by a volcanic eruption.

   

• Crater: It is a bowl shaped depression formed at the mouth of a volcano. It is formed due to the repeated eruption of a volcano.

   

• Caldera: Due to the repeated eruption of a volcano, its summit may be blown away a number of times. In its place a large depression called caldera is formed.

   

• Composite cone: During an eruption when a volcano throws away both- lava and large fragments of rocks, multiple layers of these two materials gets built up resulting in the formation of a composite cone.

   

• Volcanic shields: When lava gets solidified after flowing away from the vent, it forms a broad summit with a gentle base, and a volcanic shield is formed.
• Lava plateau: A plateau is formed when a volcano constantly erupts over a long time at frequent intervals over a largearea throwing away lava and fragments of rocks (pyroclasts). The Deccan Plateau is one such example.