Source: NCERT Official Textbook
The chapter provides a detailed explanation of earthquakes, describing them as the shaking of the Earth caused by the sudden release of energy along faults. It breaks down the different types of seismic waves (P, S, and surface waves), how they propagate, and how the study of their shadow zones has been crucial in revealing the Earth’s layered structure.
This structure consists of the brittle crust, the thick mantle (with its weak, magma-generating asthenosphere), and the heavy metallic core. The final section explores volcanoes and volcanic landforms, classifying volcanoes into types like shield, composite, and caldera, and linking massive features like the Deccan Traps to flood basalt eruptions.
It also describes various intrusive landforms like batholiths, dykes, and sills, which are formed when magma cools and solidifies within the Earth’s crust.
What are the two major deep drilling projects mentioned as direct sources of information? (Pg. 1)
The difference between the observed and expected gravity value at a location is called: (Pg. 2)
The point on the Earth’s surface directly above the focus of an earthquake is called the: (Pg. 2)
Which type of body wave can travel only through solid materials? (Pg. 3)
Which type of earthquake is generated due to the sliding of rocks along a fault plane? (Pg. 3)
The magnitude of an earthquake is measured on which scale? (Pg. 4)
Which of the following is NOT a layer of the Earth’s interior as described in the chapter? (Pg. 5)
What is the approximate mean thickness of the continental crust? (Pg. 5)
Which type of volcano is characterized by highly fluid basalt lava and a broad, gentle slope? (Pg. 6-7)
The Deccan Traps in India are an example of which volcanic formation? (Pg. 7)
Which intrusive form is described as a large, dome-shaped granitic body that cools at great depth? (Pg. 8)
(Exercise) Which one of the following earthquake waves is more destructive? (Pg. 8)
(Exercise) Which one of the following is a direct source of information about the interior of the earth? (Pg. 8)
(Exercise) Which type of volcanic eruptions have caused Deccan Trap formations? (Pg. 8)
(Exercise) Which one of the following describes the lithosphere: (Pg. 8)
The deepest drill at Kola in the Arctic Ocean has reached a depth of ______ km. (Pg. 1) Page 18
Meteors provide information about the Earth’s interior because their material and structure are ______ to that of the Earth. (Pg. 2) Page 19
The point inside the Earth where earthquake energy is released is called the ______ or hypocenter. (Pg. 2) Page 19
______ waves are the first to arrive at the surface and can travel through all states of matter. (Pg. 3) Page 20
Earthquakes induced by the explosion of chemical or nuclear devices are called ______ earthquakes. (Pg. 4) Page 21
The ______ scale measures the visible damage caused by an earthquake. (Pg. 4) Page 21
The uppermost part of the mantle, which is the main source of magma, is called the ______. (Pg. 5) Page 22
The core is sometimes referred to as the ______ layer due to its composition of nickel and iron. (Pg. 6) Page 23
Highly explosive volcanoes that collapse into a depression are called ______. (Pg. 7) Page 24
A near-horizontal body of intrusive igneous rock is called a ______ or sheet. (Pg. 8) Page 25
(Exercise) Name the direct sources of information about the interior of the earth. (Pg. 9) Page 26
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