Geography · General Awareness

Geology and Earth Structure

1,345 Questions

Geology and Earth Structure explores the physical composition of the planet, including its layers, tectonic plates, and seismic activity. This topic is a core component of geography and general science sections in various competitive exams. Reviewing these concepts builds a solid foundation for answering questions related to natural phenomena.

Layers of the EarthTectonic PlatesEarthquakes and VolcanoesGeomagnetism ApplicationsGeophysical MethodsLandform Formation

Geology and Earth Structure Questions

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

The uppermost layer over the earth's surface is called the ____________.

  1. Crust

  2. Mantle

  3. Outer core

  4. Inner core
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The three main layers of Earth include the crust (1 percent of Earth's volume), the mantle (84 percent), and the core (inner and outer combined, 15 percent). The outermost of all these three is the crust. 

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

Which of the following statement is correct?

  1. The crust is thicker in the oceans than the continents

  2. The crust is thinner in the continents than on the ocean floors

  3. The crust is thinner in the ocean floors than the continents

  4. The crust is thicker in the continents than in the ocean floors
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • The average thickness of earth crust at ocean floors- 8 km 
  • The average thickness of earth crust at continents- 32 km
  • Thus the earth crust is thicker at continents as compared to oceans floors.
Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

 Mohorovicic discontinuity is the boundary between ________ and _________.

  1. crust and core

  2. mantle and core

  3. crust and mantle

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Mohorovicic Discontinuity, or Moho is the boundary between the crust and the mantle. This boundary is located at approximately 2891 km depth beneath the Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth. This discontinuity is due to the differences between the acoustic impedances of the solid mantle and the molten outer core.


Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

The name of the layer of the Earth that separates the crust from the core is the ___?

  1. magma

  2. lithosphere

  3. mantle

  4. asthenosphere
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Earth mainly consists of four layers namely crust, mantle, outer core and inner core.

Mantle is the widest of all the layers, which is 1800 miles thick. It is composed mostly of silicate rocks rich in magnesium and iron. It is found beneath the earth’s crust. The temperature of this layer is 1600 degrees Fahrenheit at the top to about 4000 degrees Fahrenheit near the bottom.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

The Mohorovicic Discontinuity marks the _____ limit of Earth's crust.

  1. lower

  2. upper

  3. middle

  4. side
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Mohorovicic Discontinuity marks the lower limit of Earth's crust. It occurs at an average depth of about 8 kilometers beneath the ocean basins and 32 kilometers beneath continental surfaces. Mohorovicic was able to use his discovery to study thickness variations of the crust. He discovered that the oceanic crust has a relatively uniform thickness, while continental crust is thickest under mountain ranges and thinner under plains.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

Third layer of Earth which comes after Mantle of Earth is known as __________________.

  1. The Inner Core

  2. The Crust

  3. The Outer Core

  4. The Mantle
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Earth mainly consists of four layers namely crust, mantle, outer core and inner core:

Crust: This is about 8 km thick inside and is highly explored. The continental crust is composed mostly of granite. The oceanic crust consists of a volcanic lava rock called basalt.

Mantle: It is the largest layer of the Earth which is 1800 miles thick. It is composed mostly of silicate rocks rich in magnesium and iron.

Outer core: It is located beneath the mantle. The outer core is composed of melted metals like nickel and iron.

Inner core: It is composed of an iron-nickel alloy and some light elements.

Layer that lies immediately after the mantle is the outer core.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

In geology the word __________  is used for a surface at which seismic waves change velocity.

  1. continuity

  2. discontinuity

  3. mental

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In geology the word "discontinuity" is used for a surface at which seismic waves change velocity. One of these surfaces exists at an average depth of 8 kilometers beneath the ocean basin and at an average depth of about 32 kilometers beneath the continents. At this discontinuity, seismic waves accelerate. This surface is known as the Mohorovicic Discontinuity or often simply referred to as the "Moho."

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

Which of the following statement is false?

  1. the P-wave shadow zone is larger than the S-wave shadow zone.

  2. P waves travel more slowly in the outer core than in the lower mantle

  3. Liquids do not transmit S waves

  4. Seismic waves follow curved paths through the interior of the Earth
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All seismic waves do not cause earth quake. Certain magnitude is necessary to cause an earthquake.

Region on earth’s surface where earth quake can be barely detected after an occurrence of a seismic wave is called shadow region.

In the given options all are correct but the statement ‘P-wave shadow zone is larger than the S-wave shadow zone’ is false and vice versa is true.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

What drives plate tectonics?

  1. Thermal convection

  2. Solar energy

  3. thermal conduction

  4. Erosion
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Tectonic plates are those that are present beneath the earth surface and have been moving throughout the earth’s history.

What drives tectonic plates is not known clearly but one theory is that the convection drives heated up plates to move towards the surface and after they reach the ceiling they are deflected sideways. 

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

Where is the Earth's magnetic field generated?

  1. In the outer core

  2. In the inner core

  3. In the crust

  4. In the mantle
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Earth’s magnetic field exerts from earth’s interior to the outer surface.

Inner core is mostly made of iron and temperature is about 5,700°C, at this temperature iron is as hot as surface of sun, but crushing pressure caused by gravity prevents it from becoming liquid and hence cannot produce magnetic field.

But the outer core has a 2,000 km thick layer of iron, nickel, and small quantities of other metals. As the pressure is lower in outer core when compared to the inner core metals exists in fluid state. 

Differences in temperature, pressure and composition within the outer core cause convection currents in the molten metal and earths spin result in whirling movements of the liquid metal resulting in generation of electric currents and there by producing magnetic field.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

The boundary between the mantle and the core lies at a depth of approximately ________ .

  1. 3000 kilometers

  2. 300 kilometers

  3. 1000 kilometres

  4. 5000 kilometers
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Earth mainly consists of four layers namely crust, mantle, outer core and inner core.

The boundary between the mantle and the core lies at a depth of approximately 2891 km or 3000km.

The core–mantle boundary of the Earth lies between the planet's silicate mantle and its liquid iron-nickel outer core

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

The earth is made up of several __________ .

  1. concentric layears

  2. compositional layers

  3. structural layers

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The earth is made up of three layers, one inside the other like an onion. They are the crust, the mental and the core. The topmost layer, that is, the crust is solid, the thinnest and the lighter. The average density is 2.75 to 2.90. The thickness is 8 to 100 km. Below this top layer is the layer of basalt rock which is heavier than the topmost layer, i.e, the mental. The average thickness is 100 2900 km and the density varies from 3.1 to 5.00. The innermost layer is the core. The core contains 1/3 of the entire mass of the world. The average density is 5.1 to 13.00.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

What region of the Earth takes up the greatest volume?

  1. the inner core

  2. the crust

  3. the mantle

  4. the outer core
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Earth mainly consists of four layers namely crust, mantle, outer core and inner core.

Widest of all the layers of earth is Mantle which is 1800 thick. It is composed mostly of silicate rocks rich in magnesium and iron.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

Which one of the following lists most accurately describes oceanic crust?

  1. granitic - density of 3.0 $g/cm^3$
  2. basaltic - density of 3.0 $g/cm^3$
  3. basaltic - density of 2.6 $g/cm^3$

  4. quartz arenites - density of 2.6 g/cm3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Basalt is dark coloured igneous rock mainly composed of pyroxene mineral. It most commonly forms as an extrusive rock, such as a lava.The oceanic crust consists of a volcanic lava rock called basalt. Oceanic crust is the thin crust underlying the oceans.

Basalt density present is equal to 3.0 g /cm'3