Internal forces MCQ Quiz - Objective Question with Answer for Internal forces - Download Free PDF

The correct answer is Option 3 (Both 1 and 2).

Key Points

• Convergent plate boundaries are regions where two tectonic plates collide, resulting in intense geological activities like earthquakes, volcanic eruptions, and mountain-building processes.
• At convergent boundaries, oceanic plates often undergo subduction, where the denser oceanic plate is forced beneath a lighter continental plate or another oceanic plate.
• Subduction zones are the primary sites for intense seismic activity because of the immense stress and friction caused by the downward movement of the oceanic plate.
• Major earthquake-prone regions like the Pacific Ring of Fire are located along convergent plate boundaries.

Additional Information

• Seismic Activity: Seismic activity refers to the frequency, type, and size of earthquakes experienced in a specific area. It is most intense at plate boundaries, especially convergent and transform boundaries, due to the movement of tectonic plates.
• Subduction Zones: These are regions where one tectonic plate moves under another and sinks into the mantle. Subduction zones are associated with deep ocean trenches, volcanic arcs, and earthquakes.
• Divergent Plate Boundaries: Unlike convergent boundaries, divergent boundaries are where plates move apart, leading to the formation of new crust, mid-ocean ridges, and less intense seismic activity.
• Transform Plate Boundaries: At transform boundaries, plates slide past each other horizontally, causing strike-slip faults and earthquakes. However, these regions do not involve subduction.

The correct answer is Energy release by Tectonic movement.

Key Points

• Earthquakes caused by tectonic movements are the most widespread and devastating, as they result from the release of massive amounts of energy stored in the Earth's crust.
• The primary mechanism involves the movement of tectonic plates along faults, with the majority of earthquakes occurring at plate boundaries (e.g., subduction zones, transform faults, and divergent boundaries).
• The energy released during tectonic earthquakes travels as seismic waves, causing ground shaking, structural damage, and triggering secondary effects like landslides and tsunamis.
• Notable examples of tectonic earthquakes include the 2004 Indian Ocean earthquake (causing the tsunami) and the 2011 Tōhoku earthquake in Japan.
• Tectonic earthquakes are responsible for the largest proportion of global seismic activity, making them a key focus for disaster preparedness and mitigation strategies.

Additional Information

• Terminology: Faults and Seismic Waves:
  • A fault is a fracture in the Earth's crust along which movement has occurred.
  • Seismic waves are vibrations caused by the release of energy, classified into primary (P), secondary (S), and surface waves.
• Other Causes of Earthquakes:
  • Volcanic Eruptions: Localized earthquakes can occur due to magma movement beneath volcanoes.
  • Landslides: Large landslides can generate minor seismic activity but are not widespread.
  • Subsidence: Caused by mining or groundwater depletion, these are localized phenomena.
• Earthquake Magnitude and Intensity:
  • Magnitude: Measures the energy released during an earthquake (e.g., Richter or Moment Magnitude Scale).
  • Intensity: Assesses the effects on people, structures, and the Earth's surface (e.g., Modified Mercalli Intensity Scale).
• Global Distribution:
  • Earthquakes are predominantly concentrated in the "Ring of Fire", a tectonically active zone encircling the Pacific Ocean.
  • Other seismically active regions include the Himalayan Belt and the Mid-Atlantic Ridge.
• Preparedness:
  • Implementing earthquake-resistant infrastructure and early warning systems can mitigate impacts.
  • Public awareness and regular disaster drills are crucial for reducing casualties.

The correct answer is on earth surface.

Key Points

• The epicentre of an earthquake is the point on the earth's surface that is directly above the hypocenter or the focus.
• It is the location where the earthquake waves first reach the surface, and it is often the area that experiences the most severe shaking.
• Seismologists use the epicentre to determine the location of the earthquake and to assess the potential damage in that area.
• The distance from the epicentre to a given location is called the epicentral distance, which is important for seismic intensity calculations.

 Additional Information

• of origin of Earthquake
  • This refers to the hypocenter or focus, which is the actual location within the Earth where the earthquake originates.
  • The hypocenter is typically located beneath the Earth's surface, and it is the point where the strain energy stored in the rocks is first released.
• locus of plates
  • This term is not commonly used in seismology. However, it might refer to the boundary or interaction zones of tectonic plates where earthquakes are likely to occur.
  • These boundaries are known as fault lines and can be sites of significant geological activity.

The correct answer is Option 3.

Key Points

• Accelerometers are used in health monitoring devices to detect physical activity levels by measuring changes in motion.  
• Drones use accelerometers to detect orientation and maintain stability during flight. 
• Accelerometers are also used in earthquake monitoring systems to detect vibrations and monitor building stability. Hence, option 3 is correct.

The correct answer is Lithosphere.

Key Points

• Natural earthquakes occur primarily in the lithosphere, which is the rigid outermost layer of the Earth.
• The lithosphere consists of the Earth's crust and the uppermost part of the mantle, where tectonic plates interact, leading to seismic activity.
• Earthquakes are caused by the sudden release of energy due to movement along faults or the interaction of tectonic plates.
• Most earthquakes are concentrated along tectonic plate boundaries, including divergent, convergent, and transform boundaries.
• The lithosphere is characterized by its brittle behavior, making it prone to fracturing and generating seismic waves during an earthquake.

Additional Information

• Asthenosphere:
  • The asthenosphere lies below the lithosphere and is a semi-fluid layer of the mantle.
  • It allows tectonic plates in the lithosphere to move over it but does not experience earthquakes due to its ductile nature.
• Seismic Waves:
  • Earthquakes generate seismic waves, which are classified as primary (P) waves, secondary (S) waves, and surface waves.
  • These waves are responsible for the shaking felt during an earthquake.
• Tectonic Plate Boundaries:
  • Earthquakes are most common along tectonic plate boundaries, including subduction zones, fault lines, and rift zones.
  • The "Ring of Fire" in the Pacific Ocean is one of the most seismically active regions in the world.
• Richter Scale:
  • The magnitude of an earthquake is measured using the Richter scale, which quantifies the energy released during an event.
  • Significant earthquakes often register above 5.0 on this scale.
• Earthquake Safety:
  • Safety measures include drop, cover, and hold during shaking, and ensuring buildings are constructed to withstand seismic forces.
  • Preparedness can significantly reduce casualties and damage during an earthquake.

• Block mountains are the type of mountains in which the middle part of the mountain is lower and the parts on both sides are higher. 
• The middle part is known as the rift valley. 
• Black Forest (Germany), Salt Range (Pakistan), Vindhya and Satpura (India) are examples of block mountains. 
• The Ural is a fold mountain. Fold mountains are formed because of folds in the rocks due to the internal movements of the earth. 
• Block mountains - 

The correct answer is Aleutian Islands.

Key Points

• The Aleutian Islands are part of the Aleutian arc, one of the most active volcanic provinces on Earth, and they owe their existence to long-term volcanic activity. 
• The Aleutian Islands extend south-southwest for 1800 km from the Alaska Peninsula.
• It occupies a total area of 6821 square miles.
• It extends in an arc southwest, then northwest, for about 1100 miles from the tip of the Alaska Peninsula to Attu Island, Alaska, US.
• It separates the Bering Sea from the main portion of the Pacific Ocean.
• The archipelago consists of 14 large islands, some 55 smaller islands, and innumerable islets.
• The Ring of Fire also referred to as the Circum-Pacific Belt, is a path along the Pacific Ocean characterized by active volcanoes and frequent earthquakes.
• The Ring of Fire is stretched to approximately 40,000 kilometers tracing boundaries between several tectonic plates including the Pacific, Juan de Fuca, Cocos, Indian-Australian, Nazca, North American, and Philippine Plates.
• The chain runs up along the western coast of South and North America crosses over the Aleutian Islands in Alaska, runs down the eastern coast of Asia past New Zealand, and into the northern coast of Antarctica.
• Bolivia, Chile, Ecuador, Peru, Costa Rica, Guatemala, Mexico, United States, Canada, Russia, Japan, Philippines, Australia, Papua New Guinea, Indonesia, New Zealand, and Antarctica are some of the important places located in the ring of the fire.
• There are 512 active volcanoes.

• Block mountains are the type of mountains in which the middle part of the mountain is lower and the parts on both sides are higher. 
• The middle part is known as the rift valley. 
• Black Forest (Germany), Salt Range (Pakistan), Vindhya and Satpura (India) are examples of block mountains. 
• The Ural is a fold mountain. Fold mountains are formed because of folds in the rocks due to the internal movements of the earth. 

The correct answer is Tamu Massif.

• Tamu Massif is an extinct underwater shield volcano in the northwest Pacific Ocean, characterised by a hybrid of a mid-ocean ridge and a shield volcano.
• Tamu Massif the largest known volcano on Earth.
• Tamu Massif is situated about 1,600 km east of Japan in the Shatsky Rise.
• The volcano, which forms the entire Shatsky Rise, occupies an area of approximately 553,000 square kilometers.
• Its peak is 1,980 m below the surface of the ocean, and its base is about 6.4 km long. The volcano is 4.460 meters (14.620 ft) tall.

Important Points

• Ojos del Salado:
  • ​It is an active stratovolcano in the Andes on the border between Argentina and Chile and the highest active volcano in the world at 6,893 m (22,615 ft).
• Mount Vesuvius:
  • It is a somma-stratovolcano situated on the Gulf of Naples in Campania, Italy.
• Mauna Kea:
  • ​It is a dormant volcano on the island of Hawaii.

All of the above options are correct.

Key Points

• The Magnitude of an Earthquake is measured on a Richter scale and the Intensity of an earthquake is measured on the Mercalli scale
• The sudden movement of tectonic plates leads to an earthquake.
• Tectonic plates are constantly shifting as they drift around on the viscous, or slowly flowing, mantle layer.
• The forces which act in the interior of the earth are called Endogenic forces.
• The forces that work on the surface of the earth are called Exogenic forces.
• Endogenic forces sometimes produce sudden movements like Earthquakes and Volcanoes.

The correct answer is Mount Merapi.

Key Points

• Mount Merapi, Indonesia’s active volcano on Java island has shown dangers with small eruptions.
• The last eruption from this volcano killed more than 350 people in 2010. Any public activity including hiking within a 3 km radius has been prohibited and villagers nearby have been asked to leave.

Key PointsP and S Waves:

• Body waves are generated due to the release of energy at the focus and move in all directions travelling through the body of the earth.
• There are two types of body waves.
  • They are called P and S-waves.
• P-waves:
  • They move faster and are the first to arrive at the surface.
  • These are also called ‘primary waves’.
  • The P-waves are similar to sound waves.
  • They travel through gaseous, liquid and solid materials.
  • P waves are characterized by a back-and-forth motion of particles parallel to the direction of wave propagation.
  • On the other hand, S waves, also known as secondary waves or shear waves, cause particles to vibrate perpendicular to the direction of wave propagation, creating an up-and-down or side-to-side motion. Hence statement 2 is correct
• S-waves:
  • They arrive at the surface with some time lag.
  • These are called secondary waves.
  • An important fact about S-waves is that they can travel only through solid materials.

Seismograph:

• In a seismograph, P waves are recorded earlier than S waves.
• P waves, also known as primary waves or compressional waves, are the fastest seismic waves and can travel through both solids and liquids.
• They arrive at a seismograph station before the arrival of S waves, which are slower and arrive after the P waves.
• Therefore, P waves are recorded earlier than S waves in a seismograph. Hence statement 1 is correct

The correct answer is Plate Tectonics.

• Due to plate tectonics, the lithosphere move over the asthenosphere.

Key Points

• The lithosphere is the rocky outer part of the Earth.
• It is made up of the brittle crust and the top part of the upper mantle.
• The lithosphere is the coolest and most rigid part of the Earth. 
• There are two types of lithosphere:
  •   Oceanic lithosphere and continental lithosphere. Oceanic lithosphere is associated with oceanic crust and is slightly denser than continental lithosphere.

  Additional Information

• Plate Tectonics:
  • The most well-known feature associated with Earth’s lithosphere is tectonic activity. Tectonic activity describes the interaction of the huge slabs of the lithosphere called tectonic plates.
  • The lithosphere is divided into tectonic plates including the North American, Caribbean, South American, Scotia, Antarctic, Eurasian, Arabian, African, Indian, Philippine, Australian, Pacific, Juan de Fuca, Cocos, and Nazca.
  • The movement of tectonic plates is made possible by thermal energy (heat) from the mantle part of the lithosphere. Thermal energy makes the rocks of the lithosphere more elastic. 

Important Points 

The correct answer is Convergent.

Key Points

• Convergent Boundaries
  • When two tectonic plates move toward each other and collide, they form a convergent plate boundary.
  • There are three types of convergent plate boundaries: oceanic-oceanic boundaries, oceanic-continental boundaries, and continental-continental boundaries. Each one is unique because of the density of the plates involved.
  • Convergent plate boundaries are often the sites of earthquakes, volcanoes, and other significant geological activity.

Additional Information

• Divergent boundaries
  • A divergent boundary occurs when two tectonic plates move away from each other.
  • The Mid-Atlantic Ridge is an example of divergent plate boundaries.
• Transform
  • Transform boundaries are places where plates slide sideways past each other.
  • Transform boundaries are found on the seafloor, where they connect segments of diverging mid-ocean ridges.

The correct answer is North America.

Key Points

• Gondwanaland:
  • It was an ancient supercontinent that broke up about 180 million years ago.
  • The Gondwana land included India, Australia, South Africa, and South America as one single landmass.
  • Gondwana became the largest piece of the continental crust of the Paleozoic.
  • Gondwana existed from the Neoproterozoic period, that is, around 550 million years ago.
  • During the Eocene period, the Drake passage was opened up separating Antarctica and South America.
  • The continent of Gondwana was named by the Austrian scientist Eduard Suess, after the Gondwana region of central India which is derived from Sanskrit for 'forest of the Gonds'.
  • As per the earlier definition, Gondwana was not considered a supercontinent, as the landmasses of Siberia, Laurentia, Baltica were separated from it.
  • During the Paleozoic era, the largest piece of continental crust was the Gondwana, it was about 1/5th of the earth's surface.
  • Gondwana merged with Euramerica, during the Carboniferous period, to form the larger supercontinent called Pangea.
  • However, during the Mesozoic era, Pangea and Gondwana broke up.
  • Two-thirds of today's continental area is made up of Gondwana which includes the Indian subcontinent, Australia, Antarctica, Arabia, Zealandia, Africa, and South America.