Seismology MCQs for FPSC Assistant Meteorologist
Explanation
Seismology MCQs for FPSC Assistant Meteorologist (with Answers)
Seismology MCQs are specific to the FPSC Assistant Meteorologist syllabus, covering earthquake magnitude and intensity scales, seismic wave types, fault mechanics, plate boundaries, seismic hazard assessment, earthquake engineering and Pakistan’s seismic risk profile. This page contains 100 free MCQs with detailed explanations. Tap any option to check your answer instantly.
Showing all 100 MCQs
Q1. Seismology is the scientific study of:
- A. Only ocean tides
- B. Only weather patterns
- C. Only volcanic gases
- D. Earthquakes and the propagation of seismic waves through the Earth
Show Answer & Explanation
Correct Answer: D
Seismology is the branch of geophysics concerned with the study of earthquakes and the propagation of the elastic (seismic) waves they generate through the Earth.
Q2. An earthquake’s magnitude is a measure of:
- A. Only the depth of the earthquake
- B. The energy released at the earthquake’s source
- C. The damage caused at a specific location
- D. Only the duration of shaking
Show Answer & Explanation
Correct Answer: B
Magnitude is a measure of the total energy released at an earthquake’s source (the focus), and is a single value for a given earthquake regardless of location.
Q3. Earthquake intensity, unlike magnitude, refers to:
- A. A satellite measurement only
- B. The observed effects and severity of shaking at a specific location, which can vary across an affected area
- C. The energy released at the source
- D. The type of fault involved
Show Answer & Explanation
Correct Answer: B
Intensity describes the observed strength of shaking and the resulting effects at a particular location, and therefore varies from place to place for the same earthquake, unlike the single magnitude value.
Q4. Which scale is commonly used to describe earthquake intensity based on observed effects and damage?
- A. Fujita scale
- B. Richter scale
- C. Modified Mercalli Intensity scale
- D. Beaufort scale
Show Answer & Explanation
Correct Answer: C
The Modified Mercalli Intensity scale rates earthquake severity based on observed effects on people, buildings and the natural environment at a given location, using Roman numerals typically from I to XII.
Q5. The point within the Earth where an earthquake rupture originates is called the:
- A. Seismic gap
- B. Epicentre
- C. Focus (or hypocentre)
- D. Fault line
Show Answer & Explanation
Correct Answer: C
The focus, or hypocentre, is the actual point within the Earth’s crust where the earthquake rupture originates and seismic energy is first released.
Q6. The point on the Earth’s surface directly above the earthquake’s focus is called the:
- A. Focus
- B. Tremor zone
- C. Epicentre
- D. Fault
Show Answer & Explanation
Correct Answer: C
The epicentre is the point on the Earth’s surface located directly above the focus (hypocentre) of an earthquake.
Q7. A seismograph (or seismometer) is used to:
- A. Measure wind speed
- B. Measure rainfall
- C. Detect and record ground motion caused by seismic waves
- D. Measure atmospheric pressure
Show Answer & Explanation
Correct Answer: C
A seismograph is an instrument that detects and records ground motion, including the vibrations caused by seismic waves from an earthquake.
Q8. Pakistan’s location along which major tectonic boundary makes it seismically active?
- A. The mid-Atlantic ridge
- B. The Pacific Ring of Fire exclusively
- C. No significant tectonic boundary
- D. The boundary of the Indian and Eurasian tectonic plates
Show Answer & Explanation
Correct Answer: D
Pakistan lies along the collision zone of the Indian and Eurasian tectonic plates, particularly in the north, making the northern and western regions of the country highly seismically active.
Q9. PMD’s National Seismic Monitoring Centre also carries responsibility for early warning of which related hazard?
- A. Locust swarms
- B. Tsunami
- C. Crop disease
- D. Drought
Show Answer & Explanation
Correct Answer: B
PMD’s National Seismic Monitoring & Tsunami Early Warning Centre carries the dual responsibility of seismic monitoring and issuing tsunami early warnings for Pakistan’s coastline.
Q10. A tsunami is most commonly generated by:
- A. Tidal cycles
- B. Strong surface winds alone
- C. Heavy rainfall over the ocean
- D. A sudden, large vertical displacement of the seafloor, often caused by an undersea earthquake
Show Answer & Explanation
Correct Answer: D
Tsunamis are most commonly generated by a sudden, large vertical displacement of the seafloor, typically resulting from an undersea earthquake, though submarine landslides and volcanic activity can also cause them.
Q11. An aftershock is best defined as:
- A. A smaller earthquake that follows a larger main earthquake in the same area, as the crust adjusts
- B. A larger earthquake preceding the main event
- C. A type of tsunami
- D. A seismic instrument
Show Answer & Explanation
Correct Answer: A
An aftershock is a smaller earthquake that occurs in the same general area following a larger main earthquake, as the crust adjusts to the stress redistribution caused by the main event.
Q12. Seismic microzonation refers to:
- A. Rainfall distribution mapping
- B. Mapping an area to identify variation in earthquake shaking hazard based on local soil and geological conditions
- C. Weather zone classification
- D. Cyclone track prediction
Show Answer & Explanation
Correct Answer: B
Seismic microzonation involves detailed mapping of an area to identify how local soil type, geology and topography can amplify or reduce earthquake shaking hazard at a fine spatial scale, informing building codes.
Q13. The Richter scale, historically used to express earthquake magnitude, is:
- A. A logarithmic scale, where each whole number increase represents a tenfold increase in measured amplitude
- B. Based only on damage observed
- C. Identical to the Mercalli scale
- D. A linear scale
Show Answer & Explanation
Correct Answer: A
The Richter scale is logarithmic, meaning each increase of one whole number represents a tenfold increase in the measured amplitude of seismic waves, and roughly a 31-times increase in energy released.
Q14. The Moment Magnitude Scale (Mw), now widely preferred over the original Richter scale, is considered more accurate because it:
- A. Better estimates the total energy released, especially for very large earthquakes
- B. Only measures small earthquakes
- C. Ignores fault size
- D. Cannot be used globally
Show Answer & Explanation
Correct Answer: A
The Moment Magnitude Scale calculates energy release based on the physical size of fault rupture, the amount of slip and rock rigidity, giving more accurate readings for very large earthquakes than the original Richter scale.
Q15. P-waves (primary waves) generated by an earthquake are characterised by:
- A. Being the fastest seismic waves, travelling as compressional waves through solids, liquids and gases
- B. Only travelling through liquids
- C. Being the slowest seismic waves
- D. Only surface movement
Show Answer & Explanation
Correct Answer: A
P-waves are the fastest seismic waves, moving as compressional (push-pull) waves that can travel through solid, liquid and gaseous materials, and are therefore the first waves detected at a seismograph.
Q16. S-waves (secondary waves) generated by an earthquake:
- A. Are identical to P-waves
- B. Travel only through gases
- C. Travel faster than P-waves
- D. Travel slower than P-waves and cannot pass through liquids
Show Answer & Explanation
Correct Answer: D
S-waves are slower than P-waves and move as a shearing motion, which means they cannot propagate through liquids, a property used to help determine the structure of the Earth’s interior.
Q17. Surface waves generated by an earthquake, arriving after P- and S-waves, are generally responsible for:
- A. Only underwater effects
- B. The least damage
- C. The most severe ground shaking and damage at the surface
- D. No structural impact
Show Answer & Explanation
Correct Answer: C
Surface waves, though slower than body waves (P- and S-waves), typically have the largest amplitude and are responsible for most of the severe shaking and structural damage experienced during an earthquake.
Q18. A seismic gap refers to:
- A. A segment of an active fault that has not experienced a significant earthquake for an unusually long time, suggesting accumulated stress
- B. An earthquake-free zone permanently
- C. The depth of an earthquake focus
- D. A type of seismograph malfunction
Show Answer & Explanation
Correct Answer: A
A seismic gap is a section along an active fault zone that has been notably quiet for longer than expected historically, potentially indicating accumulated strain and future earthquake risk.
Q19. Liquefaction during an earthquake refers to the phenomenon where:
- A. Water-saturated, loose soil temporarily loses strength and behaves like a liquid due to intense shaking
- B. Only surface water evaporates
- C. Rock melts due to friction
- D. Buildings become lighter
Show Answer & Explanation
Correct Answer: A
Liquefaction occurs when intense ground shaking causes water-saturated, loosely packed soil to lose its structural strength and behave like a liquid, often causing severe foundation failure.
Q20. A foreshock is best described as:
- A. The same as an aftershock
- B. A smaller earthquake occurring after the main earthquake
- C. Always larger than the main earthquake
- D. A smaller earthquake occurring before a larger earthquake in the same area, sometimes recognised only in retrospect
Show Answer & Explanation
Correct Answer: D
A foreshock is a smaller earthquake that occurs before a larger main earthquake in the same general area, though such events are often only identifiable as foreshocks in hindsight, after the larger earthquake occurs.
Q21. Which type of fault movement involves horizontal sliding of rock masses past each other, with little vertical displacement?
- A. Reverse (thrust) fault
- B. Strike-slip fault
- C. Normal fault
- D. No such fault type exists
Show Answer & Explanation
Correct Answer: B
A strike-slip fault involves primarily horizontal movement, with rock on either side of the fault sliding laterally past each other with minimal vertical displacement.
Q22. A normal fault typically occurs in an area experiencing:
- A. Tension (extension) of the Earth’s crust
- B. Only lateral movement
- C. Compression
- D. No stress at all
Show Answer & Explanation
Correct Answer: A
A normal fault forms where the crust is under tension (being pulled apart), causing one block to drop relative to the other along the fault plane.
Q23. A reverse (thrust) fault typically occurs in an area experiencing:
- A. Compression, pushing one block up and over another
- B. Only vertical subsidence
- C. Tension
- D. No stress at all
Show Answer & Explanation
Correct Answer: A
A reverse or thrust fault forms under compressional stress, where one block of rock is pushed up and over the adjacent block along the fault plane, common in collision zones like northern Pakistan.
Q24. Which northern Pakistan region has experienced some of the country’s most destructive documented earthquakes?
- A. Coastal Sindh
- B. The Hazara-Kashmir region, including areas affected by the 2005 earthquake
- C. Southern Punjab plains
- D. Central Balochistan desert
Show Answer & Explanation
Correct Answer: B
The Hazara-Kashmir region of northern Pakistan, situated along the collision zone of the Indian and Eurasian plates, has experienced some of the country’s most destructive earthquakes.
Q25. An earthquake’s ‘depth of focus’ classification of ‘shallow’ generally refers to a focus depth of:
- A. More than 500 km
- B. Exactly at the surface only
- C. Less than about 70 km
- D. Beyond 1000 km
Show Answer & Explanation
Correct Answer: C
Shallow-focus earthquakes are generally defined as having a focus depth of less than about 70 kilometres, and they tend to cause more intense surface shaking than deeper earthquakes of similar magnitude.
Q26. Which instrument network configuration allows seismologists to determine an earthquake’s epicentre location?
- A. Only historical records
- B. A single seismograph station is always sufficient
- C. Only satellite imagery
- D. Data from at least three separated seismograph stations, using triangulation of arrival time differences
Show Answer & Explanation
Correct Answer: D
Determining an earthquake’s epicentre typically requires data from at least three seismograph stations at different locations, using the difference in P-wave and S-wave arrival times at each station to triangulate the source.
Q27. Building codes in seismically active areas primarily aim to:
- A. Prevent all earthquakes from occurring
- B. Apply only to government buildings
- C. Increase construction cost with no safety benefit
- D. Ensure structures can withstand expected ground shaking without total collapse, protecting occupant lives
Show Answer & Explanation
Correct Answer: D
Seismic building codes establish design and construction standards intended to help structures withstand expected levels of ground shaking, primarily to prevent catastrophic collapse and protect occupant lives, even if some damage occurs.
Q28. The branch of geophysics that studies the internal structure of the Earth using seismic waves is called:
- A. Meteorology
- B. Seismology
- C. Climatology
- D. Hydrology
Show Answer & Explanation
Correct Answer: B
Seismology is the branch of geophysics that studies earthquakes and uses the behaviour of seismic waves to investigate the Earth’s internal structure.
Q29. Which seismic wave type is confined to travel only along the Earth’s surface?
- A. S-waves
- B. P-waves
- C. None; all waves travel through the interior
- D. Surface waves (Love and Rayleigh waves)
Show Answer & Explanation
Correct Answer: D
Surface waves, including Love waves and Rayleigh waves, travel only along the Earth’s surface, arriving after the body waves (P- and S-waves) and typically causing the most damage.
Q30. A Rayleigh wave causes ground particles to move in what pattern?
- A. An elliptical, rolling motion, similar to ocean waves
- B. Purely up and down with no horizontal component
- C. Purely side to side
- D. No movement at all
Show Answer & Explanation
Correct Answer: A
Rayleigh waves cause ground particles to move in a rolling, elliptical pattern, similar to waves on the surface of the ocean, combining vertical and horizontal motion.
Q31. A Love wave causes ground movement that is:
- A. Horizontal, side-to-side, perpendicular to the direction of wave travel
- B. Purely vertical
- C. Only found deep underground
- D. Identical to a P-wave
Show Answer & Explanation
Correct Answer: A
Love waves cause horizontal, side-to-side ground motion perpendicular to the direction the wave is travelling, and they typically arrive slightly before Rayleigh waves.
Q32. The instrument used to record the amplitude and timing of ground motion for later analysis is called a:
- A. Anemometer
- B. Hygrograph
- C. Barograph
- D. Seismograph (or seismometer)
Show Answer & Explanation
Correct Answer: D
A seismograph, or seismometer, is the instrument that detects and records ground motion caused by seismic waves, producing a record called a seismogram.
Q33. The visual record produced by a seismograph is called a:
- A. Isogram
- B. Hydrograph
- C. Sonogram
- D. Seismogram
Show Answer & Explanation
Correct Answer: D
A seismogram is the visual trace produced by a seismograph, showing the amplitude and timing of ground motion recorded during and after an earthquake.
Q34. An earthquake’s ‘return period’ refers to:
- A. The estimated average time interval between earthquakes of a similar magnitude in a given area
- B. The duration of a single earthquake
- C. The depth of the earthquake focus
- D. The time it takes seismic waves to return to the source
Show Answer & Explanation
Correct Answer: A
Return period is a statistical estimate of the average time interval expected between earthquakes of a similar magnitude occurring in a specific region, used in seismic hazard assessment.
Q35. Earthquake early warning systems work by detecting which wave first to provide warning before more damaging waves arrive?
- A. The faster-travelling but generally less damaging P-waves
- B. Tsunami waves
- C. Only aftershocks
- D. Surface waves
Show Answer & Explanation
Correct Answer: A
Early warning systems detect the fast-travelling but generally weaker P-waves first, providing a short warning window of seconds before the slower, more destructive S-waves and surface waves arrive.
Q36. Which of the following best describes ‘ground acceleration’ in the context of earthquake engineering?
- A. A measure of how rapidly the ground shakes during an earthquake, important for structural design
- B. The depth of an earthquake’s focus
- C. The speed at which an earthquake travels globally
- D. The colour coding on a hazard map
Show Answer & Explanation
Correct Answer: A
Ground acceleration measures how rapidly and forcefully the ground shakes during an earthquake, a critical parameter used by structural engineers to design earthquake-resistant buildings.
Q37. A seismic hazard map is primarily used to:
- A. Measure rainfall distribution
- B. Show the relative likelihood and expected intensity of ground shaking across different areas
- C. Track weather patterns
- D. Predict the exact date of future earthquakes
Show Answer & Explanation
Correct Answer: B
A seismic hazard map illustrates the relative probability and expected intensity of ground shaking across a region, based on historical earthquake activity and known fault locations, informing building codes and land use planning.
Q38. Which of the following is an example of a secondary hazard commonly triggered by a major earthquake?
- A. Lower air pressure
- B. Reduced rainfall
- C. Increased solar radiation
- D. Landslides and liquefaction
Show Answer & Explanation
Correct Answer: D
Landslides and liquefaction are common secondary hazards triggered by strong earthquake shaking, often causing damage beyond that caused directly by the ground shaking itself.
Q39. The ‘Ring of Fire’ refers to a zone around which ocean, known for intense seismic and volcanic activity?
- A. Arctic Ocean
- B. Pacific Ocean
- C. Indian Ocean
- D. Atlantic Ocean
Show Answer & Explanation
Correct Answer: B
The Ring of Fire is a horseshoe-shaped zone around the Pacific Ocean basin, associated with a large concentration of the world’s earthquakes and active volcanoes due to tectonic plate boundaries.
Q40. Which type of seismic instrument network allows for rapid determination of an earthquake’s location and magnitude across a wide region?
- A. Only satellite imagery
- B. Weather radar
- C. A single isolated seismograph
- D. A distributed network of interconnected seismograph stations
Show Answer & Explanation
Correct Answer: D
A distributed network of interconnected seismograph stations allows seismologists to rapidly triangulate an earthquake’s location and estimate its magnitude by comparing data from multiple sites simultaneously.
Q41. Building retrofitting in seismically active zones refers to:
- A. Constructing entirely new buildings only
- B. Painting buildings a different colour
- C. Demolishing old buildings only
- D. Modifying existing structures to improve their resistance to earthquake shaking
Show Answer & Explanation
Correct Answer: D
Retrofitting involves strengthening or modifying existing buildings and infrastructure to improve their ability to withstand earthquake shaking, without necessarily constructing an entirely new structure.
Q42. Which factor most influences how much damage a given earthquake magnitude causes in a populated area?
- A. Population density, building construction quality, and distance from the epicentre
- B. The name of the fault
- C. The time of year only
- D. The colour of local buildings
Show Answer & Explanation
Correct Answer: A
The extent of damage from an earthquake of a given magnitude depends heavily on population density, the quality and type of local building construction, and proximity to the epicentre, not on magnitude alone.
Q43. Which agency is internationally recognised for compiling a comprehensive global earthquake catalogue?
- A. World Meteorological Organization
- B. International Civil Aviation Organization
- C. United States Geological Survey (USGS)
- D. World Health Organization
Show Answer & Explanation
Correct Answer: C
The United States Geological Survey (USGS) maintains one of the most comprehensive and widely referenced global earthquake catalogues, monitoring seismic activity worldwide.
Q44. An earthquake’s ‘focal depth’ classification of ‘intermediate’ generally refers to a depth range of approximately:
- A. Over 1000 km
- B. 70 to 300 km
- C. 0 to 10 km
- D. 500 to 700 km
Show Answer & Explanation
Correct Answer: B
Intermediate-focus earthquakes are generally classified as occurring at depths of roughly 70 to 300 kilometres, between shallow-focus and deep-focus events.
Q45. Deep-focus earthquakes, occurring at depths beyond roughly 300 km, are most commonly associated with:
- A. Divergent plate boundaries
- B. Volcanic hotspots only
- C. Subduction zones, where one plate sinks beneath another
- D. Transform boundaries only
Show Answer & Explanation
Correct Answer: C
Deep-focus earthquakes are most commonly associated with subduction zones, where a denser oceanic plate is forced deep beneath another plate, generating stress at significant depth.
Q46. Which of these best describes ‘seismic risk’, as distinct from seismic hazard?
- A. The physical probability of ground shaking alone
- B. The combination of seismic hazard with the vulnerability and exposure of people and infrastructure in the affected area
- C. Only relevant to insurance companies
- D. A term identical in meaning to seismic hazard
Show Answer & Explanation
Correct Answer: B
Seismic risk combines the physical seismic hazard (likelihood and intensity of shaking) with the vulnerability of structures and the exposure of population and assets, providing a fuller picture of potential consequences than hazard alone.
Q47. Which type of building material generally performs poorly under strong seismic shaking if not specifically reinforced?
- A. Unreinforced masonry (brick or stone without reinforcement)
- B. Steel frame construction
- C. Reinforced concrete with seismic detailing
- D. Timber frame construction
Show Answer & Explanation
Correct Answer: A
Unreinforced masonry structures, lacking steel reinforcement, are generally among the most vulnerable building types under strong seismic shaking, prone to sudden and often catastrophic collapse.
Q48. Base isolation is an earthquake engineering technique that works by:
- A. Decoupling a building’s structure from ground motion using flexible bearings, reducing the shaking transmitted to the building
- B. Removing all foundations entirely
- C. Making a building heavier
- D. Increasing the building’s height
Show Answer & Explanation
Correct Answer: A
Base isolation places flexible bearings or isolators between a building’s foundation and its superstructure, absorbing and reducing the amount of ground shaking energy transmitted into the building itself.
Q49. Which of these best describes a ‘micro-earthquake’?
- A. A type of tsunami
- B. A very large, damaging earthquake
- C. A volcanic eruption
- D. A very small earthquake, generally of magnitude below about 3, often undetectable without instruments
Show Answer & Explanation
Correct Answer: D
A micro-earthquake is a very small seismic event, typically of magnitude below approximately 3, usually undetectable by humans and only recorded by sensitive seismographic instruments.
Q50. Induced seismicity refers to earthquakes that:
- A. Only occur in the deep ocean
- B. Occur entirely independent of any human activity
- C. Are triggered or influenced by human activities, such as large reservoir impoundment, fluid injection or mining
- D. Cannot be studied scientifically
Show Answer & Explanation
Correct Answer: C
Induced seismicity refers to earthquakes triggered or influenced by human activities, such as filling a large reservoir behind a dam, injecting fluids underground, or extensive mining operations.
Q51. Reservoir-induced seismicity is a phenomenon sometimes observed following:
- A. Small ponds being drained
- B. Weather forecasting activities
- C. Ocean tidal changes alone
- D. The filling of large reservoirs behind major dams, altering stress on nearby faults
Show Answer & Explanation
Correct Answer: D
Reservoir-induced seismicity refers to earthquake activity sometimes triggered by the filling of large reservoirs behind major dams, where the added water weight and pressure can alter stress conditions on nearby geological faults.
Q52. A seismic zoning map divides a region into different zones based primarily on:
- A. Rainfall patterns
- B. The relative level of expected earthquake hazard, used to guide building codes and land use planning
- C. Agricultural productivity
- D. Population density alone
Show Answer & Explanation
Correct Answer: B
A seismic zoning map divides a region into zones reflecting the relative level of expected earthquake hazard, providing a basis for differentiated building codes and land use planning decisions.
Q53. Which of these organisations plays a key role in Pakistan’s national earthquake monitoring and response coordination, alongside PMD?
- A. IRSA
- B. National Disaster Management Authority (NDMA)
- C. PCRWR
- D. WAPDA
Show Answer & Explanation
Correct Answer: B
The National Disaster Management Authority (NDMA) plays a key coordinating role in Pakistan’s earthquake response and disaster management, working alongside PMD’s seismic monitoring capability.
Q54. The moment magnitude scale calculates earthquake energy based on which physical parameters?
- A. Only the duration of shaking felt
- B. Only the number of aftershocks
- C. The area of fault rupture, the average slip distance, and the rigidity of the rock involved
- D. Only the population affected
Show Answer & Explanation
Correct Answer: C
The moment magnitude scale calculates the seismic moment based on the physical parameters of fault rupture area, average slip (displacement) along the fault, and the rigidity of the surrounding rock, providing a physically grounded measure of earthquake size.
Q55. Which of these best describes an ‘active fault’?
- A. A fault only found underwater
- B. A term with no scientific definition
- C. A fault considered likely to produce future earthquakes, based on evidence of relatively recent movement
- D. A fault that has never moved in recorded history
Show Answer & Explanation
Correct Answer: C
An active fault is one considered likely to generate future earthquakes, generally identified by evidence of movement within a geologically recent timeframe, such as the last 10,000 to 100,000 years depending on the classification criteria used.
Q56. A ‘dormant’ or ‘inactive’ fault is one that:
- A. Always produces the largest earthquakes
- B. Shows no evidence of movement for a very long geological period and is considered unlikely to produce significant future earthquakes
- C. Is currently moving rapidly
- D. Cannot be identified by geologists
Show Answer & Explanation
Correct Answer: B
A dormant or inactive fault shows no evidence of significant movement over a very long geological timeframe and is generally considered to pose a lower risk of producing significant future earthquakes, compared with an active fault.
Q57. Which of the following best describes ‘seismic retrofitting priorities’ typically applied first in a resource-constrained setting?
- A. Decorative building features
- B. Private garden walls
- C. Non-structural interior decorations only
- D. Critical infrastructure such as hospitals, schools and emergency response facilities
Show Answer & Explanation
Correct Answer: D
In resource-constrained settings, seismic retrofitting is typically prioritised for critical infrastructure such as hospitals, schools and emergency facilities, given their essential role during and after a disaster.
Q58. Which seismic parameter is most directly used by structural engineers to design a building’s earthquake resistance for a specific location?
- A. Design ground acceleration or design spectral acceleration for that location
- B. Historical rainfall data
- C. Population density
- D. Average annual temperature
Show Answer & Explanation
Correct Answer: A
Structural engineers use design ground acceleration or design spectral acceleration values, derived from seismic hazard assessments for a specific location, as a key input for designing earthquake-resistant structures.
Q59. Which of these is the primary purpose of an earthquake drill in schools and offices?
- A. To familiarise occupants with safe response actions, improving their ability to react appropriately during an actual earthquake
- B. To evaluate air conditioning performance
- C. To disrupt normal activities
- D. To test fire alarm systems only
Show Answer & Explanation
Correct Answer: A
Earthquake drills familiarise occupants with safe response actions, such as ‘drop, cover, and hold on’, improving their ability to react quickly and appropriately if a real earthquake occurs.
Q60. Which of these best describes ‘site amplification’ in earthquake engineering?
- A. A term unrelated to earthquake damage
- B. Ground shaking being reduced uniformly everywhere
- C. Only relevant to underwater earthquakes
- D. Local soil and geological conditions increasing the intensity of ground shaking compared with the surrounding bedrock
Show Answer & Explanation
Correct Answer: D
Site amplification refers to how certain local soil and geological conditions, particularly soft or loose sediments, can significantly increase the intensity and duration of ground shaking compared with nearby solid bedrock.
Q61. Why are soft, unconsolidated sediments (such as those in a river valley) generally more prone to amplifying earthquake shaking than solid bedrock?
- A. They transmit seismic energy less efficiently
- B. Soft sediments block all seismic waves completely
- C. Seismic waves tend to slow down and increase in amplitude as they pass from harder rock into softer sediment
- D. They are always located far from fault lines
Show Answer & Explanation
Correct Answer: C
As seismic waves pass from harder bedrock into softer, unconsolidated sediment, their velocity typically decreases while their amplitude increases, a physical effect that leads to amplified shaking intensity at the surface.
Q62. Which of these terms describes a sequence of numerous smaller earthquakes occurring in a region without one identifiable dominant main shock?
- A. A tsunami sequence
- B. A seismic gap event
- C. A single mainshock-aftershock sequence
- D. An earthquake swarm
Show Answer & Explanation
Correct Answer: D
An earthquake swarm refers to a sequence of many earthquakes occurring within a relatively short time and confined area, without one single, much larger, dominant mainshock, often associated with volcanic or geothermal activity.
Q63. Which of these best describes a ‘triggered earthquake’?
- A. An earthquake with no identifiable cause
- B. An earthquake whose occurrence is influenced by the stress changes caused by a separate, often larger, nearby earthquake
- C. A term used exclusively for volcanic earthquakes
- D. A synonym for an aftershock only
Show Answer & Explanation
Correct Answer: B
A triggered earthquake is one whose occurrence is influenced by stress changes transmitted from a separate earthquake, sometimes occurring on a different, nearby fault system.
Q64. Which seismic wave type is typically used to determine the depth of an earthquake’s focus?
- A. The relative arrival time difference between P-waves and S-waves at multiple stations
- B. Only surface waves
- C. Wind speed data
- D. Only Love waves
Show Answer & Explanation
Correct Answer: A
By analysing the arrival time difference between P-waves and S-waves recorded at multiple seismograph stations, seismologists can calculate both the distance to, and the depth of, an earthquake’s focus.
Q65. A ‘strainmeter’ is an instrument used in seismology to measure:
- A. Very small deformations or strain in the Earth’s crust, which can indicate stress buildup along a fault
- B. Atmospheric pressure
- C. Rainfall intensity
- D. Wind speed
Show Answer & Explanation
Correct Answer: A
A strainmeter measures extremely small deformations in the Earth’s crust, providing data on stress accumulation along faults that may be relevant to earthquake hazard assessment.
Q66. A GPS-based geodetic monitoring network is used in seismology primarily to:
- A. Measure rainfall
- B. Monitor ocean temperatures
- C. Detect slow, ongoing crustal deformation and movement associated with tectonic plate motion and fault stress buildup
- D. Track weather balloons
Show Answer & Explanation
Correct Answer: C
GPS-based geodetic networks precisely track the slow, ongoing movement and deformation of the Earth’s crust, providing valuable data on tectonic plate motion and stress accumulation along active faults.
Q67. Which of these best explains why earthquake prediction (specifying the exact time, location and magnitude in advance) remains scientifically unreliable?
- A. Earthquakes follow a perfectly predictable schedule
- B. The complex, chaotic nature of stress accumulation and release along faults makes precise short-term prediction currently unattainable with existing science
- C. Seismographs cannot detect any earthquakes
- D. Earthquakes only occur randomly with no underlying physical process at all
Show Answer & Explanation
Correct Answer: B
Despite significant scientific effort, the complex and effectively chaotic nature of stress accumulation and release along fault systems currently makes precise short-term earthquake prediction, specifying exact time, location and magnitude, scientifically unreliable.
Q68. Earthquake forecasting, as distinct from prediction, typically provides:
- A. A probabilistic estimate of earthquake likelihood over a longer time period for a given region
- B. No useful information at all
- C. Only information about past earthquakes
- D. An exact date and time for a specific earthquake
Show Answer & Explanation
Correct Answer: A
Unlike precise prediction, earthquake forecasting provides probabilistic estimates of earthquake likelihood for a given region over a longer time period, based on historical patterns and current understanding of fault behaviour.
Q69. Which of these is a commonly cited historical earthquake that struck Pakistan’s Kashmir/Hazara region in 2005?
- A. A magnitude 5.0 earthquake with minimal damage
- B. A major magnitude 7.6 earthquake causing widespread devastation and significant loss of life
- C. A deep-focus earthquake with no surface impact
- D. An earthquake confined entirely to neighbouring India
Show Answer & Explanation
Correct Answer: B
The 2005 Kashmir earthquake, of approximately magnitude 7.6, was a major and highly destructive event affecting the Hazara-Kashmir region, causing widespread devastation and significant loss of life.
Q70. Which of these is a common structural weakness that increases building vulnerability during earthquakes, often called a ‘soft storey’?
- A. Extremely thick foundation walls
- B. Uniformly strong walls on every floor
- C. A building with no floors above ground level
- D. A ground floor with significantly less structural strength or stiffness than the floors above, such as due to large openings for shops or parking
Show Answer & Explanation
Correct Answer: D
A ‘soft storey’ refers to a building floor, often the ground floor, with significantly reduced structural stiffness or strength compared with the floors above, commonly due to large openings for shops, garages or parking, making that floor prone to concentrated damage or collapse during shaking.
Q71. Which factor most directly determines whether liquefaction is likely to occur at a given site during an earthquake?
- A. Only the season of the year
- B. The presence of loose, saturated, sandy soil combined with sufficiently strong ground shaking
- C. Only the building’s height
- D. Only the earthquake’s magnitude
Show Answer & Explanation
Correct Answer: B
Liquefaction risk depends primarily on the presence of loose, water-saturated, granular soil (such as sand) combined with ground shaking of sufficient intensity and duration to cause the soil to lose its strength.
Q72. Which of these best describes the purpose of ‘seismic gap’ analysis in hazard assessment?
- A. To measure rainfall along fault lines
- B. To identify areas guaranteed to never experience an earthquake
- C. To identify segments along an active fault that have not ruptured recently and may therefore be at elevated risk of a future significant earthquake
- D. To calculate the cost of past earthquake damage
Show Answer & Explanation
Correct Answer: C
Seismic gap analysis identifies segments along an active fault system that have not experienced a significant earthquake for an unusually long time relative to the surrounding fault, which may indicate elevated future earthquake risk due to accumulated but unreleased stress.
Q73. An intensity scale, such as the Modified Mercalli scale, is generally considered more useful than a magnitude scale for which specific purpose?
- A. Predicting future earthquakes
- B. Describing the varying local severity of shaking and damage experienced across different specific locations
- C. Determining an earthquake’s exact depth
- D. Comparing the total energy released by different earthquakes globally
Show Answer & Explanation
Correct Answer: B
An intensity scale is particularly useful for describing how the severity of shaking and resulting damage varies from place to place for a single earthquake, since intensity depends on local factors such as distance from the epicentre and soil conditions, unlike magnitude which is a single fixed value for the whole event.
Q74. Which of these best describes ‘aseismic’ fault movement?
- A. Movement that always produces very large earthquakes
- B. A fault that has stopped moving forever
- C. Gradual, slow slip along a fault that occurs without generating significant earthquakes
- D. A type of tsunami
Show Answer & Explanation
Correct Answer: C
Aseismic fault movement, sometimes called fault creep, refers to slow, gradual slip along a fault plane that releases accumulated stress without generating significant, felt earthquakes.
Q75. Which type of seismic wave typically has the largest amplitude and is most responsible for structural damage in a typical shallow earthquake?
- A. S-waves
- B. There is no difference in amplitude between wave types
- C. P-waves
- D. Surface waves
Show Answer & Explanation
Correct Answer: D
Surface waves, arriving after the faster body waves (P- and S-waves), typically carry the largest amplitude and are usually the primary cause of structural damage in shallow, moderate-to-large earthquakes.
Q76. Which of these is an example of a passive seismic hazard mitigation measure, as opposed to active engineering intervention?
- A. Retrofitting an existing bridge
- B. Installing base isolators in a new building
- C. Adding seismic dampers to a skyscraper
- D. Land use zoning that restricts construction in areas of highest identified seismic hazard
Show Answer & Explanation
Correct Answer: D
Land use zoning, which restricts or guides the type and density of construction permitted in areas of highest identified seismic hazard, is a passive mitigation measure operating through planning policy rather than direct structural engineering intervention.
Q77. Which of these best describes the relationship between earthquake magnitude and the frequency of occurrence, generally observed globally (the Gutenberg-Richter relationship)?
- A. Larger magnitude earthquakes occur far more frequently than smaller ones
- B. There is no relationship between magnitude and frequency
- C. Smaller magnitude earthquakes occur far more frequently than larger ones
- D. All magnitudes of earthquake occur with exactly equal frequency
Show Answer & Explanation
Correct Answer: C
The Gutenberg-Richter relationship, observed consistently across seismically active regions, shows that smaller magnitude earthquakes occur far more frequently than larger ones, with each unit increase in magnitude corresponding to roughly a tenfold decrease in frequency.
Q78. Which of these terms refers to the total energy released by an earthquake, a concept closely related to but distinct from magnitude?
- A. Fault creep
- B. Ground acceleration
- C. Seismic moment
- D. Intensity
Show Answer & Explanation
Correct Answer: C
Seismic moment is a physically based measure of the total energy released by an earthquake, calculated from fault rupture area, average slip, and rock rigidity, and forms the basis of the moment magnitude scale.
Q79. Which of these best describes a ‘tsunami warning system’?
- A. A weather satellite network only
- B. A system that only monitors rainfall
- C. A network of sensors, including seismographs and ocean sensors, designed to detect potential tsunami-generating events and issue timely alerts to coastal populations
- D. A system used only for volcanic eruptions
Show Answer & Explanation
Correct Answer: C
A tsunami warning system integrates seismographic data with ocean-based sensors such as tide gauges and deep-ocean buoys to detect potential tsunami-generating events, such as undersea earthquakes, and issue timely alerts to at-risk coastal populations.
Q80. A DART buoy (Deep-ocean Assessment and Reporting of Tsunamis) is used to:
- A. Detect changes in sea level associated with a passing tsunami wave in deep ocean water
- B. Measure wind speed at sea
- C. Track earthquake epicentres directly
- D. Measure ocean salinity only
Show Answer & Explanation
Correct Answer: A
A DART buoy system detects subtle changes in sea level caused by a passing tsunami wave while it is still in deep ocean water, transmitting this data to help confirm and refine tsunami warnings before the wave reaches the coast.
Q81. Why do tsunami waves often go largely unnoticed while travelling through deep ocean water, only becoming dangerous near the coast?
- A. They are completely invisible even near the coast
- B. They only form directly at the coastline
- C. They travel at very low speed and low amplitude everywhere
- D. In deep water they have very long wavelength and low amplitude, but as they approach shallow coastal water they slow down and dramatically increase in height
Show Answer & Explanation
Correct Answer: D
In deep ocean water, a tsunami wave typically has a very long wavelength and low amplitude, making it barely noticeable at the surface, but as it approaches shallow coastal water it slows down and its energy compresses into a much greater wave height.
Q82. Which of these is a recommended immediate safety action if strong earthquake shaking is felt while indoors?
- A. Stand in an open doorway of a modern building as the safest location in all cases
- B. Drop to the ground, take cover under sturdy furniture, and hold on until the shaking stops
- C. Run outside immediately during the shaking
- D. Use the elevator to exit the building quickly
Show Answer & Explanation
Correct Answer: B
The widely recommended immediate safety action during strong shaking is to drop to the ground, take cover under sturdy furniture such as a table, and hold on until the shaking stops, rather than attempting to run outside during the shaking itself.
Q83. Why is using an elevator strongly discouraged during and immediately after a significant earthquake?
- A. Elevators are always the fastest way to exit a building
- B. Power outages or structural damage can cause elevators to become stuck or malfunction, trapping occupants
- C. Elevators are immune to any earthquake effects
- D. There is no safety concern with elevator use during earthquakes
Show Answer & Explanation
Correct Answer: B
Earthquakes can cause power outages or structural damage that lead elevators to malfunction or become stuck, potentially trapping occupants, which is why stairs are recommended instead during and immediately after significant shaking.
Q84. Which of these best describes an ‘earthquake-resistant design philosophy’ commonly summarised as ‘strong column, weak beam’?
- A. Designing buildings so that beams fail before columns during severe shaking, helping to prevent sudden total collapse
- B. Designing buildings with no columns at all
- C. Ensuring columns always fail first
- D. Making all structural elements equally weak
Show Answer & Explanation
Correct Answer: A
The ‘strong column, weak beam’ design philosophy aims to ensure that, under severe shaking, beams yield and deform before columns, helping to prevent the sudden, catastrophic collapse of the entire structure.
Q85. Which of these best describes ‘ductility’ in the context of earthquake-resistant structural design?
- A. A measure of a building’s total weight
- B. A material’s ability to shatter suddenly under stress
- C. A measure of soil moisture content
- D. A material or structure’s ability to undergo significant deformation without breaking, absorbing seismic energy
Show Answer & Explanation
Correct Answer: D
Ductility refers to a material’s or structure’s capacity to undergo significant deformation without fracturing, which allows it to absorb and dissipate seismic energy during an earthquake rather than failing suddenly and brittlely.
Q86. A seismic damper installed in a building functions to:
- A. Absorb and dissipate the energy of seismic shaking, reducing the movement transmitted to the structure
- B. Only function during extreme heat
- C. Increase the building’s natural vibration
- D. Prevent any wind loading effects
Show Answer & Explanation
Correct Answer: A
A seismic damper is a device installed within a building’s structure to absorb and dissipate the kinetic energy generated by seismic shaking, thereby reducing the amount of movement and stress transmitted to the main structural frame.
Q87. Which of these best describes ‘community-based disaster risk reduction’ in the context of earthquake preparedness?
- A. A concept unrelated to earthquake hazards
- B. Relying solely on national government response after a disaster occurs
- C. Actively engaging local communities in identifying risks, planning, and building local capacity to prepare for, and respond to, earthquake hazards
- D. Ignoring local knowledge entirely in favour of external experts
Show Answer & Explanation
Correct Answer: C
Community-based disaster risk reduction actively involves local communities in identifying their specific risks, developing preparedness plans, and building local capacity to respond effectively to earthquake hazards, complementing broader national disaster management efforts.
Q88. Which of these best describes why historical earthquake records (the ‘earthquake catalogue’) are important for hazard assessment?
- A. They are used only for academic interest with no practical application
- B. They only apply to earthquakes occurring in the last decade
- C. They provide essential data on the frequency, magnitude, and location of past earthquakes, informing statistical estimates of future hazard
- D. They have no scientific value
Show Answer & Explanation
Correct Answer: C
Historical earthquake catalogues provide essential long-term data on the frequency, magnitude, and location of past seismic events, forming the statistical basis for estimating the probability and characteristics of future earthquake hazard in a given region.
Q89. Palaeoseismology is the scientific study of:
- A. Prehistoric earthquakes, using geological evidence such as displaced rock layers, to extend the earthquake record beyond written history
- B. Only volcanic activity
- C. Only oceanic earthquakes
- D. Only earthquakes that have occurred in the last year
Show Answer & Explanation
Correct Answer: A
Palaeoseismology studies evidence of prehistoric earthquakes, such as displaced or disturbed rock and sediment layers along fault lines, allowing scientists to extend the known earthquake record for a region far beyond the period covered by written historical records or instruments.
Q90. Which of these best describes why earthquake losses have historically increased globally, despite improved scientific understanding of seismic hazard?
- A. Rapid population growth and urbanisation, often with inadequate building standards, have significantly increased the exposure and vulnerability of people and assets
- B. Earthquakes have become significantly more frequent and powerful overall
- C. Building codes have made all structures completely earthquake-proof
- D. There is no relationship between urbanisation and earthquake losses
Show Answer & Explanation
Correct Answer: A
Despite improved scientific understanding, global earthquake losses have often increased due to rapid population growth and urbanisation, particularly where inadequate building standards leave a much larger number of people and assets exposed and vulnerable to seismic hazard.
Q91. Which of these best describes ‘fault rupture length’ and its general relationship with earthquake magnitude?
- A. Longer fault rupture lengths are generally associated with smaller magnitude earthquakes
- B. Rupture length only matters for volcanic earthquakes
- C. Longer fault rupture lengths are generally associated with larger magnitude earthquakes
- D. Fault rupture length has no relationship with magnitude
Show Answer & Explanation
Correct Answer: C
In general, a longer fault rupture length corresponds to a larger earthquake magnitude, since more of the fault plane has slipped, releasing greater total seismic energy.
Q92. Which of these instruments would be used specifically to measure tilt or slight changes in the ground’s slope, useful for monitoring volcanic or fault-related deformation?
- A. An anemometer
- B. A thermometer
- C. A tiltmeter
- D. A rain gauge
Show Answer & Explanation
Correct Answer: C
A tiltmeter is a sensitive instrument used to measure very small changes in the slope or tilt of the ground surface, useful for monitoring deformation associated with volcanic activity or fault movement.
Q93. Which of these best explains the term ‘recurrence interval’ in seismic hazard studies?
- A. The duration of a single earthquake event
- B. The distance between two earthquake epicentres
- C. The estimated average time between successive earthquakes of a similar size on a given fault or in a given region
- D. The exact date of the next earthquake
Show Answer & Explanation
Correct Answer: C
Recurrence interval refers to the estimated average time period between successive earthquakes of a similar magnitude occurring on a specific fault or within a defined seismic source region, used as a statistical tool in hazard assessment.
Q94. Which of these is generally true regarding the relationship between earthquake depth and surface damage potential, for a given magnitude?
- A. Depth has no bearing on surface shaking intensity
- B. Deeper earthquakes generally cause more severe surface shaking than shallow earthquakes of the same magnitude
- C. All earthquakes occur at exactly the same depth
- D. Shallower earthquakes generally cause more severe surface shaking and damage than deeper earthquakes of the same magnitude
Show Answer & Explanation
Correct Answer: D
For a given magnitude, shallow-focus earthquakes generally produce more intense surface shaking and greater damage potential than deeper earthquakes, since the seismic energy has less distance to travel and dissipate before reaching the surface.
Q95. Which of these describes the primary function of a ‘strong motion accelerograph’, as distinct from a standard sensitive seismograph?
- A. To detect only tsunami waves
- B. To accurately record the strong, high-amplitude ground motion close to significant earthquakes, which can saturate standard sensitive instruments
- C. To measure only earthquake sound
- D. To record extremely faint, distant earthquakes only
Show Answer & Explanation
Correct Answer: B
A strong motion accelerograph is specifically designed to accurately record the strong, high-amplitude ground acceleration experienced close to significant earthquakes, providing crucial data for earthquake engineering that standard highly sensitive seismographs may fail to capture without becoming saturated.
Q96. Which of these organisations is responsible for globally standardising and disseminating official earthquake magnitude and location information?
- A. Only university research departments with no official standardisation
- B. International seismological organisations and national agencies, often coordinating and sharing data internationally, such as through the USGS and International Seismological Centre
- C. Only individual national governments acting alone with no coordination
- D. Only private weather companies
Show Answer & Explanation
Correct Answer: B
Earthquake information is typically standardised and disseminated through coordinated international and national seismological organisations, such as the USGS and the International Seismological Centre, which compile and share data to ensure consistency in reporting earthquake parameters globally.
Q97. Which of these best describes the term ‘shaking intensity’ as experienced by people during an earthquake, distinct from an instrument reading?
- A. A synonym for magnitude with no distinction
- B. A qualitative description of the felt severity of ground motion, based on observed effects on people, objects and structures at a location
- C. A purely instrumental measurement with no human element
- D. A measurement unrelated to earthquake science
Show Answer & Explanation
Correct Answer: B
Shaking intensity describes the felt severity of ground motion at a specific location, assessed qualitatively through observed effects on people, furniture, and buildings, complementing the purely instrumental magnitude reading.
Q98. Which of these best explains why earthquake early warning systems can only provide a short warning time, often just seconds?
- A. The warning depends on detecting fast P-waves and transmitting an alert before the slower, more damaging S-waves and surface waves arrive, leaving only a brief window
- B. Earthquakes always begin with an audible warning sound
- C. Seismic waves travel instantaneously with no delay
- D. Warning systems are deliberately delayed for no technical reason
Show Answer & Explanation
Correct Answer: A
Early warning systems work by detecting the faster-travelling P-waves and rapidly transmitting an alert before the slower, more damaging S-waves and surface waves reach a given location, which inherently limits the warning time to a matter of seconds depending on distance from the epicentre.
Q99. Which of these is an example of a non-structural earthquake hazard mitigation measure inside a building?
- A. Installing base isolators
- B. Securing heavy furniture, shelving and equipment to walls to prevent them from toppling during shaking
- C. Reinforcing the building’s foundation
- D. Adding seismic dampers to the structural frame
Show Answer & Explanation
Correct Answer: B
Non-structural mitigation measures, such as securing heavy furniture, shelving units, and equipment to walls, reduce the risk of injury and damage during shaking without altering the building’s main structural framework.
Q100. Which of these best describes why coastal communities are specifically vulnerable to earthquake-generated tsunamis?
- A. Tsunamis are unrelated to seismic activity
- B. Tsunamis only affect inland areas
- C. A large undersea earthquake can generate a series of powerful ocean waves that travel rapidly and can inundate low-lying coastal areas with little warning
- D. Coastal areas are always immune to tsunami effects
Show Answer & Explanation
Correct Answer: C
Coastal communities are particularly vulnerable because a large undersea earthquake can generate a series of powerful ocean waves that travel across the ocean at high speed and can inundate low-lying coastal areas, sometimes with only minutes of warning.
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