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
  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are correct but R is not the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The structure of Earth's interior is indeed deduced using seismic waves (Assertion A is true). However, Reason R is false because it reverses the facts: P-waves (Primary) can travel through solids, liquids, AND gases, while S-waves (Shear) can ONLY travel through solids. This difference in behavior is actually what helps scientists understand Earth's internal structure.

Multiple choice
  1. crust and mantle

  2. upper mantle and lower mantle

  3. mantle and core

  4. inner core and outer core

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Mohorovicic discontinuity (Moho) is the boundary between Earth's crust and the mantle, discovered by Andrija Mohorovicic in 1909. It is characterized by a sharp increase in seismic wave velocity (from about 6-7 km/s to 8+ km/s) due to the change in composition from crustal rocks to denser mantle rocks (peridotite).

Multiple choice
  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are correct but R is not the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Correct Answer: (A) is true but (R) is false. The Earth was discovered to have a solid inner core distinct from its liquid outer core in 1936, by the seismologist Inge Lehmann, who deduced its presence by studying seismograms from earthquakes in New Zealand; she observed that the seismic waves reflect off the boundary of the inner core and can be detected by sensitive seismographs on the Earth's surface. Typical values for P-wave velocity in earthquakes are in the range 5 to 8 km/s. The precise speed varies according to the region of the Earth's interior, from less than 6 km/s in the Earth's crust to 13 km/s through the core.  

Multiple choice
  1. Internal structure

  2. Atmospheric pressure

  3. Rotation

  4. Revolution

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Earth's shape is an oblate spheroid - slightly flattened at the poles and bulging at the equator. This is caused by Earth's rotation. The centrifugal force from rotation is strongest at the equator, causing material to bulge outward there. The equatorial diameter is about 43 km greater than the polar diameter. Revolution (orbit around the Sun) and atmospheric pressure do not affect shape.

Multiple choice
  1. lithosphere

  2. aethenosphere

  3. photosphere

  4. atmosphere

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The asthenosphere (spelled 'aethenosphere' in this question) is the upper, mechanically weak layer of the mantle, extending from about 100-200 km depth to 660 km. It lies beneath the lithosphere. The lithosphere is the rigid outer layer, while photosphere relates to the Sun, and atmosphere is the gaseous envelope surrounding Earth.

Multiple choice
  1. The point of rupture is called the 'focus' and may be located near the surface or deep below it.

  2. Earthquake whose focus lies more than 300 km below the earth's surface is called 'deep focus earthquakes'.

  3. Deep focus earthquakes are very destructive.

  4. All of the above

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Deep focus earthquakes are rarely destructive because by the time the waves reach the surface, the impact reduces. Shallow focus earthquakes are more common and are extremely damaging because of their proximity to the surface.

Multiple choice
  1. S waves move objects at right angles to their direction of motion.

  2. S waves propagate through liquids.

  3. As the P waves propagate, they move material in a path parallel to the direction of movement.

  4. L waves travel along the surface of the earth's crust.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

S waves (shear waves) can only propagate through solids because they require the medium to resist shear stress. Liquids cannot support shear stress, so S waves cannot travel through them. This is why S waves cannot pass through Earth's liquid outer core. The statement 'S waves propagate through liquids' is incorrect, which is exactly what the question asks for (which statement is NOT correct).

Multiple choice
  1. divergent plate boundaries

  2. young folded mountains

  3. active volcanoes

  4. convergent plate boundaries

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The circum Pacific belt (Ring of Fire) is primarily located along convergent plate boundaries where plates collide, creating intense seismic and volcanic activity. These convergent boundaries involve subduction zones, volcanic eruptions, and frequent earthquakes. Divergent boundaries create new crust and are associated with different geological features, not the Ring of Fire.

Multiple choice
  1. The devastation caused by an earthquake

  2. The frequency of earthquakes at a particular place

  3. The amount of energy released by an earthquake

  4. All of the above

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

‘Seismograph’ measures the amount of energy released by an earthquake.

Multiple choice

Directions: Choose the most correct option out of following: What was the name given to the first Seismograph?

Seismograph: Seismologists study earthquakes by going out and looking at the damage caused by the earthquakes and by using seismographs. A seismograph is an instrument that records the shaking of the earth's surface caused by seismic waves. The term seismometer is also used to refer to the same device, and the two terms are often used interchangably. The first seismograph was invented in 132 A.D. by the Chinese astronomer and mathematician Chang Heng. He called it an earthquake weathercock. Each of the eight dragons had a bronze ball in its mouth. Whenever there was even a slight earth tremor, a mechanism inside the seismograph would open the mouth of one dragon. The bronze ball would fall into the open mouth of one of the toads, making enough noise to alert someone that an earthquake had just happened. Imperial watchman could tell which direction the earthquake came from by seeing which dragon's mouth was empty. In 136 A.D. a Chinese scientist named Choke updated this meter and called it a seismoscope. Columns of a viscous liquid were used in place of metal balls. The height to which the liquid was washed up the side of the vessel indicated the intensity and a line joining the points of maximum motion also denoted the direction of the tremor. Most seismographs today are electronic, but a basic seismograph is made of a drum with paper on it, a bar or spring with a hinge at one or both ends, a weight, and a pen. The one end of the bar or spring is bolted to a pole or metal box that is bolted to the ground. The weight is put on the other end of the bar and the pen is stuck to the weight. The drum with paper on it presses against the pen and turns constantly. When there is an earthquake, everything in the seismograph moves except the weight with the pen on it. As the drum and paper shake next to the pen, the pen makes squiggly lines on the paper, creating a record of the earthquake. This record made by the seismograph is called a seismogram. By studying the seismogram, the seismologist can tell how far away the earthquake was and how strong it was. This record doesn't tell the seismologist exactly where the epicenter was, just that the earthquake happened so many miles or kilometers away from that seismograph. To find the exact epicenter, you need to know what at least two other seismographs in other parts of the country or world recorded.

  1. Seismometer

  2. Earthquake weathercock

  3. Seismoscope

  4. Seismogram

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The first seismograph was invented in 132 A.D. by the Chinese astronomer and mathematician Chang Heng. He called it an earthquake weathercock.

Multiple choice

Directions: Choose the most correct option out of following: Which of the following was used in Choke's seismoscope?

Seismograph: Seismologists study earthquakes by going out and looking at the damage caused by the earthquakes and by using seismographs. A seismograph is an instrument that records the shaking of the earth's surface caused by seismic waves. The term seismometer is also used to refer to the same device, and the two terms are often used interchangably. The first seismograph was invented in 132 A.D. by the Chinese astronomer and mathematician Chang Heng. He called it an earthquake weathercock. Each of the eight dragons had a bronze ball in its mouth. Whenever there was even a slight earth tremor, a mechanism inside the seismograph would open the mouth of one dragon. The bronze ball would fall into the open mouth of one of the toads, making enough noise to alert someone that an earthquake had just happened. Imperial watchman could tell which direction the earthquake came from by seeing which dragon's mouth was empty. In 136 A.D. a Chinese scientist named Choke updated this meter and called it a seismoscope. Columns of a viscous liquid were used in place of metal balls. The height to which the liquid was washed up the side of the vessel indicated the intensity and a line joining the points of maximum motion also denoted the direction of the tremor. Most seismographs today are electronic, but a basic seismograph is made of a drum with paper on it, a bar or spring with a hinge at one or both ends, a weight, and a pen. The one end of the bar or spring is bolted to a pole or metal box that is bolted to the ground. The weight is put on the other end of the bar and the pen is stuck to the weight. The drum with paper on it presses against the pen and turns constantly. When there is an earthquake, everything in the seismograph moves except the weight with the pen on it. As the drum and paper shake next to the pen, the pen makes squiggly lines on the paper, creating a record of the earthquake. This record made by the seismograph is called a seismogram. By studying the seismogram, the seismologist can tell how far away the earthquake was and how strong it was. This record doesn't tell the seismologist exactly where the epicenter was, just that the earthquake happened so many miles or kilometers away from that seismograph. To find the exact epicenter, you need to know what at least two other seismographs in other parts of the country or world recorded.

  1. Metal balls

  2. Bronze balls

  3. Viscous liquid

  4. Drum

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In 136 A.D. a Chinese scientist named Choke updated this meter and called it a seismoscope. Columns of a viscous liquid were used in place of metal balls.

Multiple choice

Directions: Choose the most correct option out of following: Which of the following statements is true?

Seismograph: Seismologists study earthquakes by going out and looking at the damage caused by the earthquakes and by using seismographs. A seismograph is an instrument that records the shaking of the earth's surface caused by seismic waves. The term seismometer is also used to refer to the same device, and the two terms are often used interchangably. The first seismograph was invented in 132 A.D. by the Chinese astronomer and mathematician Chang Heng. He called it an earthquake weathercock. Each of the eight dragons had a bronze ball in its mouth. Whenever there was even a slight earth tremor, a mechanism inside the seismograph would open the mouth of one dragon. The bronze ball would fall into the open mouth of one of the toads, making enough noise to alert someone that an earthquake had just happened. Imperial watchman could tell which direction the earthquake came from by seeing which dragon's mouth was empty. In 136 A.D. a Chinese scientist named Choke updated this meter and called it a seismoscope. Columns of a viscous liquid were used in place of metal balls. The height to which the liquid was washed up the side of the vessel indicated the intensity and a line joining the points of maximum motion also denoted the direction of the tremor. Most seismographs today are electronic, but a basic seismograph is made of a drum with paper on it, a bar or spring with a hinge at one or both ends, a weight, and a pen. The one end of the bar or spring is bolted to a pole or metal box that is bolted to the ground. The weight is put on the other end of the bar and the pen is stuck to the weight. The drum with paper on it presses against the pen and turns constantly. When there is an earthquake, everything in the seismograph moves except the weight with the pen on it. As the drum and paper shake next to the pen, the pen makes squiggly lines on the paper, creating a record of the earthquake. This record made by the seismograph is called a seismogram. By studying the seismogram, the seismologist can tell how far away the earthquake was and how strong it was. This record doesn't tell the seismologist exactly where the epicenter was, just that the earthquake happened so many miles or kilometers away from that seismograph. To find the exact epicenter, you need to know what at least two other seismographs in other parts of the country or world recorded.

  1. A seismogram does not tell the intensity of an earthquake.

  2. Seismograph and seismogram are similar.

  3. Seismograph and seismometer are alike.

  4. A seismograph exactly tells the epicentre of an earthquake.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A seismograph is an instrument that records the shaking of the earth's surface caused by seismic waves. The term seismometer is also used to refer to the same device, and the two terms are often used interchangably.

Multiple choice

Directions: Choose the most correct option out of following: What kind of lines are made on the paper in a seismogram?

Seismograph: Seismologists study earthquakes by going out and looking at the damage caused by the earthquakes and by using seismographs. A seismograph is an instrument that records the shaking of the earth's surface caused by seismic waves. The term seismometer is also used to refer to the same device, and the two terms are often used interchangably. The first seismograph was invented in 132 A.D. by the Chinese astronomer and mathematician Chang Heng. He called it an earthquake weathercock. Each of the eight dragons had a bronze ball in its mouth. Whenever there was even a slight earth tremor, a mechanism inside the seismograph would open the mouth of one dragon. The bronze ball would fall into the open mouth of one of the toads, making enough noise to alert someone that an earthquake had just happened. Imperial watchman could tell which direction the earthquake came from by seeing which dragon's mouth was empty. In 136 A.D. a Chinese scientist named Choke updated this meter and called it a seismoscope. Columns of a viscous liquid were used in place of metal balls. The height to which the liquid was washed up the side of the vessel indicated the intensity and a line joining the points of maximum motion also denoted the direction of the tremor. Most seismographs today are electronic, but a basic seismograph is made of a drum with paper on it, a bar or spring with a hinge at one or both ends, a weight, and a pen. The one end of the bar or spring is bolted to a pole or metal box that is bolted to the ground. The weight is put on the other end of the bar and the pen is stuck to the weight. The drum with paper on it presses against the pen and turns constantly. When there is an earthquake, everything in the seismograph moves except the weight with the pen on it. As the drum and paper shake next to the pen, the pen makes squiggly lines on the paper, creating a record of the earthquake. This record made by the seismograph is called a seismogram. By studying the seismogram, the seismologist can tell how far away the earthquake was and how strong it was. This record doesn't tell the seismologist exactly where the epicenter was, just that the earthquake happened so many miles or kilometers away from that seismograph. To find the exact epicenter, you need to know what at least two other seismographs in other parts of the country or world recorded.

  1. Straight

  2. Beeline

  3. Direct

  4. Bumpy

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Because squiggly means bumpy.