A lens-shaped igneous mass found at the crest of an anticline or trough of a syncline is a...
- Sill
- Laccolith
- Lopolith
- Phacolith
Explanation: Phacoliths are concordant intrusive bodies that occupy the crests or troughs of folded sedimentary strata.
Which seismic waves move in a rolling motion similar to ocean waves?
- Secondary waves
- Rayleigh waves
- Primary waves
- Love waves
Explanation: Rayleigh waves are surface waves that cause the ground to shake in an elliptical, rolling motion.
Which seismic wave is purely longitudinal (compressional) in nature?
- P-wave
- L-wave
- R-wave
- S-wave
Explanation: P-waves are compressional waves where particles move back and forth in the same direction as the wave travels.
In which state or UT of India is the dormant volcano Narcondam Island located?
- Andaman and Nicobar
- Gujarat
- Odisha
- Maharashtra
Explanation: Narcondam is a small volcanic island in the Andaman Sea and is classified as a dormant volcano.
Which of the following is a classic 'Extinct' volcano?
- Mount Merapi
- Mount Kilimanjaro
- Mount Etna
- Mount Pinatubo
Explanation: Kilimanjaro is considered extinct (or dormant by some), showing no history of eruptions in written human record.
What is the term for a volcanic vent that emits only gases and water vapor?
- Fumarole
- Caldera
- Crater
- Geyser
Explanation: Fumaroles are openings in the Earth's crust that emit steam and volcanic gases like sulfur dioxide.
Which intrusive landform is a saucer-shaped body found in a concave basin?
- Laccolith
- Lopolith
- Phacolith
- Batholith
Explanation: A lopolith is a large, concordant igneous intrusion that is lenticular in shape with a depressed central region.
The Mercalli scale measures which aspect of an earthquake?
- Fault length
- Total energy
- Observed damage
- Wave amplitude
Explanation: The Modified Mercalli Intensity (MMI) scale is a qualitative measure of the effects and damage caused by an earthquake.
What term describes a mixture of volcanic water and debris flowing down a volcano?
- Pyroclastic flow
- Nuée ardente
- Lava flow
- Lahar
Explanation: A lahar is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris, and water.
A horizontal, sheet-like intrusive body formed between rock layers is a...
- Sill
- Batholith
- Dyke
- Stock
Explanation: Sills are concordant intrusions that inject magma parallel to the existing bedding planes of rock.
What is the point on the Earth's surface directly above the earthquake source?
- Nadir
- Hypocenter
- Focus
- Epicenter
Explanation: The epicenter is the surface point directly above the focus (hypocenter) where the energy is first released.
What is the approximate speed of P-waves in the Earth's crust?
- 1-2 km/s
- 5-8 km/s
- 30-40 km/s
- 15-20 km/s
Explanation: P-waves travel at speeds ranging from about 5 to 8 km per second in the crustal rocks.
An isolated volcanic peak rising from the ocean floor is called a...
- Seamount
- Atoll
- Archipelago
- Guyot
Explanation: Seamounts are underwater mountains formed by volcanic activity that do not reach the water's surface.
Basaltic lava is characterized by having...
- Explosive nature
- High gas content
- High silica content
- Low viscosity
Explanation: Basaltic (basic) lava has low silica, making it fluid and allowing it to flow great distances.
Magma with high silica content and high viscosity is generally termed as...
- Ultramafic lava
- Basic lava
- Acidic lava
- Mafic lava
Explanation: Acidic (felsic) lava is rich in silica, light-colored, and flows slowly due to its high viscosity.
The zone of seismic activity along a subducting plate is called the...
- Gutenberg zone
- Maho zone
- Conrad zone
- Benioff zone
Explanation: The Wadati-Benioff zone is a dipping planar zone of earthquakes that is produced by the interaction of a subducting oceanic crustal plate.
What is the primary characteristic of lava in a shield volcano?
- Rich in silica
- Highly viscous
- Acidic composition
- Low viscosity
Explanation: Fluid basaltic lava allows shield volcanoes to spread over wide areas, creating a broad, low-profile shape.
S-waves cannot pass through which layer of the Earth?
- Crust
- Mantle
- Outer Core
- Inner Core
Explanation: The liquid state of the Outer Core creates a shadow zone for S-waves, as they cannot propagate through fluids.
What is the primary material that forms the 'Composite' layers of a stratovolcano?
- Granite blocks
- Pure basalt
- Obsidian glass
- Ash and lava
Explanation: Composite volcanoes are built from alternating layers of lava flows, ash, and volcanic cinders.
Consider: 1. P-waves travel through all mediums. 2. S-waves travel only through solids.
- 1 only
- 2 only
- Both 1 and 2
- Neither 1 nor 2
Explanation: Primary (P) waves are longitudinal and pass through solids, liquids, and gases; Secondary (S) waves are transverse and cannot pass through liquids.
Which tectonic boundary is most associated with deep-sea trench volcanism?
- Passive
- Divergent
- Convergent
- Transform
Explanation: Volcanoes form parallel to trenches at convergent boundaries where one plate subducts under another.
The most active volcanic region, known as the 'Ring of Fire', surrounds which ocean?
- Arctic Ocean
- Atlantic Ocean
- Pacific Ocean
- Indian Ocean
Explanation: The Circum-Pacific Belt hosts about 75% of the world's active volcanoes due to extensive subduction zones.
What is the name for the very large, deep-seated intrusive bodies that form the core of mountains?
- Sills
- Dykes
- Laccoliths
- Batholiths
Explanation: Batholiths are massive igneous intrusions (over 100 sq km) that usually form deep in the crust.
Consider: 1. Love waves are the fastest surface waves. 2. Love waves cause vertical ground movement.
- 1 only
- 2 only
- Both 1 and 2
- Neither 1 nor 2
Explanation: Love waves are faster than Rayleigh waves, but they cause horizontal (side-to-side) shifting, not vertical movement.
Which volcano type is characterized by its small size and steep slopes made of pyroclastic material?
- Mid-ocean ridge
- Cinder cone
- Stratovolcano
- Shield volcano
Explanation: Cinder cones are the simplest type of volcano, built from particles and blobs of congealed lava ejected from a single vent.
Which type of earthquake typically occurs at subduction zones at great depths?
- Surface focus
- Deep focus
- Intermediate focus
- Shallow focus
Explanation: Deep-focus earthquakes occur at depths between 300 and 700 km along the Benioff zone in subduction regions.
What is the actual point of energy release within the Earth during an earthquake?
- Epicenter
- Nadir
- Focus
- Apex
Explanation: The focus, also called the hypocenter, is the point inside the Earth where the earthquake rupture starts.
What is the primary cause of the S-wave shadow zone beyond 103 degrees?
- Liquid outer core
- Mantle density
- Crustal thickness
- Solid inner core
Explanation: S-waves are transverse and cannot travel through the liquid outer core, creating a massive shadow zone opposite the epicenter.
Consider: 1. Composite volcanoes have low silica content. 2. Shield volcanoes are commonly found at hotspots.
- 2 only
- 1 only
- Both 1 and 2
- Neither 1 nor 2
Explanation: Composite volcanoes have high silica (acidic) lava; shield volcanoes like those in Hawaii are classic hotspot features.
Lines on a map connecting points that experienced the same earthquake intensity are...
- Isoseismal lines
- Isohyets
- Isogonic lines
- Isobars
Explanation: Isoseismal lines are used to map the distribution of earthquake intensity based on the Mercalli scale.
Small, pea-sized volcanic fragments ejected during an eruption are called...
Explanation: Lapilli are tephra particles ranging from 2 mm to 64 mm in diameter.
A massive, dome-shaped intrusive igneous body with a flat floor is a...
- Sill
- Laccolith
- Phacolith
- Batholith
Explanation: Laccoliths are mushroom-shaped intrusive bodies that arch the overlying strata into a dome.
The 'Elastic Rebound Theory' explains the generation of...
- Earthquakes
- Mountain folds
- Volcanic lava
- Tsunamis
Explanation: This theory states that stress builds up in rocks until they reach their breaking point, releasing energy as they snap back.
Which of the following are the most destructive seismic waves?
- Body waves
- Surface waves
- S-waves
- P-waves
Explanation: Surface waves (Love and Rayleigh waves) travel along the crust and cause the most structural damage.
What is the primary difference between magma and lava?
- Temperature
- Location
- Viscosity
- Chemical composition
Explanation: Magma refers to molten rock beneath the surface; once it erupts onto the surface, it is called lava.
Mount St. Helens is a famous example of which type of volcano?
- Composite
- Fissure
- Cinder cone
- Shield
Explanation: Mount St. Helens in the USA is a stratovolcano known for its catastrophic 1980 explosive eruption.
A vertical or near-vertical intrusive body that cuts across rock layers is a...
- Sill
- Dyke
- Lopolith
- Laccolith
Explanation: Dykes are discordant intrusions that cut across the bedding or foliation of the host rock.
What is the most common gas released during a volcanic eruption?
- Carbon dioxide
- Nitrogen
- Sulfur dioxide
- Water vapor
Explanation: Water vapor typically accounts for 60% to 90% of the total gases emitted during volcanism.
Which of the following is the world's largest active volcano by volume?
- Mauna Loa
- Mount Vesuvius
- Krakatoa
- Mount Etna
Explanation: Located in Hawaii, Mauna Loa is a shield volcano and is the largest active volcano on Earth.
Earthquakes caused by the movement of magma are known as...
- Induced earthquakes
- Volcanic earthquakes
- Tectonic earthquakes
- Collapse earthquakes
Explanation: These are associated with active volcanism and are caused by the pressure of magma against surrounding rock.
The 'Richter Scale' is a logarithmic scale used to measure...
- Damage intensity
- Fault depth
- Eruption duration
- Wave magnitude
Explanation: The Richter scale quantifies the energy released by an earthquake by measuring the amplitude of seismic waves.
Fissure eruptions are most likely to lead to the formation of...
- Calderas
- Stratovolcanoes
- Lava plateaus
- Cinder cones
Explanation: Large-scale fissure eruptions release massive amounts of fluid basalt, which covers vast areas to form plateaus like the Deccan Traps.
Which seismic waves are the first to be recorded on a seismograph?
- S-waves
- R-waves
- P-waves
- L-waves
Explanation: P-waves (Primary) are the fastest seismic waves and arrive at the recording station first.
Tsunamis are most frequently generated by earthquakes with which focal depth?
- Deep focus
- Mantle focus
- Intermediate focus
- Shallow focus
Explanation: Shallow-focus earthquakes under the seabed are the most effective at displacing water and generating tsunamis.
The world's highest active volcano, Ojos del Salado, is located in the...
- Alps
- Rockies
- Andes
- Himalayas
Explanation: Ojos del Salado is a stratovolcano in the Andes on the Argentina–Chile border and is the highest active volcano on Earth.
Which of these is the only active volcano in India?
- Narcondam Island
- Mount Girnar
- Barren Island
- Dhosi Hill
Explanation: Located in the Andaman Sea, Barren Island is the only confirmed active volcano in the Indian subcontinent.
Consider: 1. Shield volcanoes are primarily basaltic. 2. Composite volcanoes are highly explosive.
- 1 only
- 2 only
- Both 1 and 2
- Neither 1 nor 2
Explanation: Shield volcanoes have low-viscosity basaltic lava; Composite (stratovolcanoes) have viscous lava and frequent explosive eruptions.
Which scale is used to measure the intensity (destructive impact) of an earthquake?
- Saffir-Simpson scale
- Richter scale
- Mercalli scale
- Beaufort scale
Explanation: The Mercalli scale measures visible damage and human perception, whereas the Richter scale measures magnitude (energy).
Which of these is a volcanic gas vent specifically rich in sulfur?
- Fumarole
- Mofette
- Solfatara
- Geyser
Explanation: Solfataras are a type of fumarole that primarily emits sulfurous gases.
The 'shadow zone' of P-waves exists between which angular distances from the epicenter?
- 0 to 103
- 103 to 142
- 142 to 180
- 90 to 120
Explanation: P-waves are refracted by the core, leaving a 'shadow' where no direct P-waves are recorded between 103° and 142°.
Which landform is an example of a 'flood basalt' province in India?
- Deccan Traps
- Aravallis
- Himalayas
- Nilgiris
Explanation: The Deccan Traps are one of the largest volcanic features on Earth, formed by massive fissure eruptions.
Which volcanic belt is also known as the 'Circum-Pacific Belt'?
- Ring of Fire
- Mid-Continental Belt
- Mid-Atlantic Belt
- Alpine Belt
Explanation: The Ring of Fire is a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur.
What happens to the velocity of P-waves as they pass from the mantle to the outer core?
- Velocity stays constant
- Velocity decreases
- Velocity increases
- Velocity becomes zero
Explanation: P-waves slow down significantly when they move from the solid mantle into the liquid outer core due to refraction.
Which of the following is a classic example of a 'Dormant' volcano?
- Mount Stromboli
- Mount Etna
- Mount Fuji
- Mount Kilimanjaro
Explanation: Mount Fuji is considered dormant as it has not erupted since 1707 but still shows signs of potential future activity.
Which of the following describes 'Tephra'?
- Airborne volcanic debris
- Underground magma body
- Solidified lava lake
- Volcanic gas cloud
Explanation: Tephra is a general term for all rock fragments and particles ejected into the air during a volcanic eruption.
Which of the following is considered an 'Intermittent' volcano?
- Barren Island
- Mount Etna
- Mount Vesuvius
- Mount Stromboli
Explanation: Stromboli has been erupting almost continuously for 2,000 years, earning it the nickname 'Lighthouse of the Mediterranean'.
Which volcanic landform is created by the collapse of a magma chamber?
- Caldera
- Cinder cone
- Volcanic plug
- Shield volcano
Explanation: A caldera is a large, cauldron-like depression formed when a volcano collapses following a massive eruption.
A massive, very hot cloud of ash and gas that travels rapidly is called...
- Pyroclastic flow
- Solfatara
- Fumarole
- Lahar
Explanation: Pyroclastic flows (or nuée ardente) are high-density mixtures of hot, dry rock fragments and hot gases.
Which instrument is used to record the vibrations of the Earth?
- Altimeter
- Hygrometer
- Barograph
- Seismograph
Explanation: A seismograph (or seismometer) detects and records the ground motion caused by seismic waves.
Which type of volcanic eruption is the most explosive and violent?
- Strombolian type
- Icelandic type
- Plinian type
- Hawaiian type
Explanation: Plinian eruptions are the most powerful, characterized by massive columns of gas and volcanic ash extending high into the stratosphere.