Geography · General Awareness

Geology and Earth Structure

1,268 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

Moho-discontinuity is found between the

  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 Mohorovičić discontinuity (Moho) is the boundary between Earth's crust and the mantle. It was discovered by Croatian seismologist Andrija Mohorovičić in 1909 and is defined by a distinct change in seismic wave velocity, occurring at depths of 5-70 km below surface depending on location.

Multiple choice

Consider the following statements regarding earthquakes:

  1. In earthquakes, shocks are generated at a point known as the epicentre
  2. The point of origin of shock may be within the crust or mantle
  3. The more earthquake-prone areas are the margin of tectonic plates Which of the above statements are correct?

  1. 1, 2 and 3

  2. 1 and 2

  3. 1 and 3

  4. 2 and 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Statement 1 is incorrect because earthquake shocks originate at the focus (hypocenter) deep underground, not at the epicentre which is merely the surface point directly above the focus. Statement 2 is correct as earthquake foci can occur in either the crust or mantle depending on tectonic setting. Statement 3 is correct as plate margins (especially convergent and transform boundaries) are the most seismically active zones due to constant tectonic stress accumulation and release.

Multiple choice

The development of synclinal ridges and anticlinal valleys in a folder region is named as

  1. Parallel belt of valleys and ridges

  2. Abrasion platform

  3. Topograph of inversion of relief

  4. Ridge and valley landscape
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A ridge and valley landscape is characterized by alternating narrow ridges and parallel valleys that develop in folded mountain regions where differential erosion occurs. The more resistant rock layers form ridges (synclinal ridges when the resistant layer is in a syncline) while less resistant layers are eroded to form valleys (anticlinal valleys when the resistant cap is eroded from an anticline). This creates the distinctive pattern where valleys sit over anticlines and ridges over synclines - an inversion of the original structural relief.

Multiple choice

Which of the following statements are true?

  1. Moderate earthquakes are causes along constructive plate boundaries.
  2. Low magnitude earthquakes are cause along constructive plate boundaries.
  3. Disastrous earthquakes are caused along destructive caused boundaries.
  4. Severe earthquakes are caused along the conservative plate boundaries with the creation of transform faults. Select the correct answer using the codes given below;

  1. 1 and 2

  2. 1 and 3

  3. 1, 3 and 4

  4. 2, 3 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice

Match List I with List II and select the correct answer: List I (Theories/Hypothesis) A. Geosynclinal Theory B. Tetrahedral hypothesis C. Stationary Wave Theory D. Subsidence Theory List II (Hypothesis regarding origin of the earth)

  1. Origin of tides
  2. Origin of coral reefs and atolls
  3. Mountain building
  4. Origin of continents and ocean basin

  1. A 3 B 4 C 2 D 1

  2. A 4 B 3 C 2 D 1

  3. A 3 B 4 C 1 D 2

  4. A 4 B 3 C 1 D 2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The correct matching is: Geosynclinal Theory (A) relates to mountain building processes (3) - geosynclines are large sedimentary troughs that become folded into mountains. Tetrahedral Hypothesis (B) explains the origin of continents and ocean basins (4) through a tetrahedral earth model. Stationary Wave Theory (C) relates to the origin of tides (1) through standing wave patterns. Subsidence Theory (D) by Darwin explains coral reefs and atolls (2) through gradual subsidence of volcanic foundations. The correct answer is A-3, B-4, C-1, D-2.

Multiple choice

Which one of the following is a third-order relief?

  1. Abyssal

  2. Cliffs

  3. Plateau

  4. Trench
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

First-order relief includes continents and ocean basins. Second-order relief includes mountains, plateaus, plains, and major depressions. Third-order relief includes minor features like cliffs, ravines, dunes, and small hills formed by secondary processes acting on larger landforms.

Multiple choice

Hawaii Island are known for active volcanoes because

  1. They are locked in the subduction zone of the covering plates

  2. faults and fractures are found there

  3. They are situated over a hot plume

  4. they are situated on a mild oceanic ridge with rising convective currents
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hawaii's volcanoes are located over a hotspot - a mantle plume of rising hot material that remains stationary while the Pacific Plate moves over it. This intraplate volcanism is NOT caused by subduction zones (no subduction beneath Hawaii), normal faulting, or mid-ocean ridge activity. The hotspot creates magma as the plume rises, resulting in active shield volcanoes.

Multiple choice

Consider the following statements in relations to Earth's topmost layer:

  1. Transverse earthquake waves moves at a speed of 3.5 km/second in that layer.
  2. The specific gravity is 2.7.
  3. It is shallowest under Continents and deepest under Oceans.
  4. Abundance of magnesium. Which of the above statements are correct

  1. 1 and 2

  2. 2 and 3

  3. 3 and 4

  4. 1, 2 and 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Statements 1 and 2 are correct about the Earth's crust (topmost layer). S waves travel at approximately 3.5 km/s in the crust, and the specific gravity is about 2.7 (crust is less dense than mantle). Statement 3 is incorrect - the crust is thickest (deepest) under continents (30-50 km) and thinnest under oceans (5-10 km). Statement 4 is incorrect - the crust is abundant in silica and aluminum (sial), not magnesium (which dominates the mantle).

Multiple choice

Consider the following statements:

  1. A tectonic scrap is steel slope that results from differential movement of the earth's surface.
  2. The typical angel of repose for scraps of all origins is between 25o to 40o.
  3. A scrap produced by structurally controlled erosion at an ancient fault is known as fault-line scrap.
  4. A capable fault is one that shows movement at or near the ground surface at least once within the past 35,000 years. Which of the above statements are correct?

  1. 1, 2, 3, and 4

  2. 2, 3, and 4

  3. 1 and 3

  4. 2 and 3
Reveal answer Fill a bubble to check yourself
C Correct answer
Multiple choice

Match the List I with List II and select the correct answer? List I (Technical Terms) List II (Definition) A. Magma Chamber 1. A point on earth's surface where impact of the arthquake is felt maximum B. Epicentre 2. An opening in the earth's crust Through which magma flows Out C. Vent 3. A point below the earth's surface where the earthquake originates D. Seismic Focus 4. A place below the earth's surface where lawa is formed and act as a source of magma outflow

  1. A 3 B 1 C 2 D 4

  2. A 3 B 2 C 1 D 4

  3. A 4 B 2 C 1 D 3

  4. A 4 B 1 C 2 D 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The correct matching is: Magma Chamber (A→4) is where lava forms underground; Epicentre (B→1) is the surface point of maximum earthquake impact; Vent (C→2) is an opening through which magma flows out; Seismic Focus (D→3) is the subsurface point where earthquake originates.

Multiple choice

Which is the largest recorded earthquake?

  1. In US (California) - 1964

  2. In Chile - 1960

  3. In US (Alaska) - 1957

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

The 1960 Valdivia earthquake in Chile registered magnitude 9.5 on the moment magnitude scale, making it the most powerful earthquake ever recorded instrumentally. It caused extensive damage across southern Chile and triggered tsunamis that affected the entire Pacific Ocean basin.

Multiple choice

Oceanic waves cause by an earthquake are known as

  1. S-waves

  2. L-waves

  3. P-waves

  4. Tsunamis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Tsunamis are large oceanic waves generated by sudden displacement of water, typically from submarine earthquakes, volcanic eruptions, or underwater landslides. S-waves, P-waves, and L-waves are types of seismic waves that travel through the Earth during earthquakes, not the oceanic waves they produce.

Multiple choice

Which of the following factors supports the hypothesis of the permanency of ocean basins and continents? The cross section of the ocean basin, comprising the broad abyssal trough flanked by rim-like continental shelves Occurrence of shallow-water sands and muds limited to the continental shell and slope, while that of pelagic oozes being limited to the abyssal plain

  1. Absence of normal sedimentary rocks on the oceanic islands.

Select the correct answer using the codes given below :

  1. 2 and 3

  2. 1 and 3

  3. 1 and 2

  4. 1, 2 and 3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The permanency hypothesis is supported by the cross-sectional structure of ocean basins with abyssal troughs and continental shelves (1), and the absence of normal sedimentary rocks on oceanic islands (3), which suggests ocean basins are permanent features rather than temporary. Option 2 is also correct but the question asks to select the correct combination, which is (b) 1 and 3.

Multiple choice

Earthquake is caused by _____.

  1. disturbance of earth surface

  2. adjustment of layers of earth crust

  3. breakage of rock system

  4. upliftment of rocks
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Earthquake is caused by disturbance of earth surface