Earthquakes, Tsunami and Volcanoes - Practice Test 1

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.The point of origin of an earthquake within the Earth is called:

   • A.Epicenter
   • B.Focus (Hypocenter)✓ Correct Answer
   • C.Crater
   • D.Core

   Explanation: The point where the energy is released inside the Earth is called the Focus or Hypocenter.

2. Q2.The point on the Earth's surface vertically above the focus is called:

   • A.Hypocenter
   • B.Epicenter✓ Correct Answer
   • C.Fault
   • D.Vent

   Explanation: The Epicenter is the point on the surface directly above the Focus.

3. Q3.Which instrument is used to record earthquake waves?

   • A.Barometer
   • B.Seismograph✓ Correct Answer
   • C.Hygrometer
   • D.Thermometer

   Explanation: A Seismograph (Seismometer) detects and records ground motion.

4. Q4.Which scale measures the magnitude (energy released) of an earthquake?

   • A.Mercalli Scale
   • B.Richter Scale✓ Correct Answer
   • C.Mohs Scale
   • D.Kelvin Scale

   Explanation: The Richter Scale measures magnitude on a logarithmic scale (0-10).

5. Q5.Which scale measures the intensity (damage caused) of an earthquake?

   • A.Richter Scale
   • B.Mercalli Scale✓ Correct Answer
   • C.Beaufort Scale
   • D.pH Scale

   Explanation: The Modified Mercalli Scale measures intensity based on observed damage (I-XII).

6. Q6.Which seismic waves are the fastest and arrive first?

   • A.S-waves
   • B.L-waves
   • C.P-waves✓ Correct Answer
   • D.R-waves

   Explanation: P-waves (Primary waves) are the fastest seismic waves.

7. Q7.Which seismic waves are also known as 'Surface Waves'?

   • A.P-waves
   • B.S-waves
   • C.L-waves✓ Correct Answer
   • D.Body waves

   Explanation: L-waves (Love/Rayleigh waves) travel along the surface.

8. Q8.Which seismic waves cause the most destruction?

   • A.P-waves
   • B.S-waves
   • C.L-waves✓ Correct Answer
   • D.Sound waves

   Explanation: Surface waves (L-waves) have high amplitude and duration, causing the most damage.

9. Q9.P-waves can travel through:

   • A.Solids only
   • B.Liquids only
   • C.Gases only
   • D.Solids, Liquids, and Gases✓ Correct Answer

   Explanation: P-waves are longitudinal and can pass through all states of matter.

10. Q10.S-waves cannot travel through:

    • A.Solids
    • B.Liquids✓ Correct Answer
    • C.Both
    • D.None

    Explanation: S-waves are shear waves and disappear in liquids (like the outer core).

11. Q11.The zone where no seismic waves are detected is called:

    • A.Blind Zone
    • B.Shadow Zone✓ Correct Answer
    • C.Dark Zone
    • D.Silent Zone

    Explanation: The Shadow Zone is created due to refraction and non-transmission of waves by the core.

12. Q12.The P-wave shadow zone is located between:

    • A.105° and 145°✓ Correct Answer
    • B.90° and 100°
    • C.105° and 180°
    • D.30° and 60°

    Explanation: It appears as a band between 105° and 145° from the epicenter.

13. Q13.Sudden shaking of the Earth's crust is called:

    • A.Volcano
    • B.Earthquake✓ Correct Answer
    • C.Landslide
    • D.Weathering

    Explanation: An earthquake is the shaking of the Earth's surface caused by energy release.

14. Q14.Most earthquakes occur along:

    • A.Plate Boundaries✓ Correct Answer
    • B.Center of Plates
    • C.Ocean floor only
    • D.Mountains only

    Explanation: Earthquakes are concentrated along tectonic plate boundaries.

15. Q15.The 'Ring of Fire' accounts for about what percentage of world earthquakes?

    • A.10%
    • B.40%
    • C.68-70%✓ Correct Answer
    • D.90%

    Explanation: The Circum-Pacific Belt (Ring of Fire) experiences about 68% of all earthquakes.

16. Q16.What is a Tsunami?

    • A.Cyclonic storm
    • B.Harbour wave caused by undersea earthquake✓ Correct Answer
    • C.Tidal wave due to moon
    • D.River flood

    Explanation: Tsunami is a Japanese word ('Tsu' = Harbour, 'Nami' = Wave) generated by undersea disturbances.

17. Q17.Tsunamis are usually generated by:

    • A.Undersea Earthquakes✓ Correct Answer
    • B.Strong winds
    • C.Tides
    • D.Global warming

    Explanation: Vertical displacement of the ocean floor during an earthquake causes tsunamis.

18. Q18.The speed of a tsunami wave in deep ocean is:

    • A.Very slow
    • B.Very fast (up to 800 km/h)✓ Correct Answer
    • C.Moderate
    • D.Zero

    Explanation: In deep water, tsunamis travel at jet speeds but have low amplitude.

19. Q19.What happens to a tsunami wave as it approaches the shore?

    • A.Speed increases, Height decreases
    • B.Speed decreases, Height increases✓ Correct Answer
    • C.Speed and Height both increase
    • D.It disappears

    Explanation: Friction slows the wave, causing water to pile up (shoaling), increasing height.

20. Q20.The 2004 Indian Ocean Tsunami was caused by an earthquake near:

    • A.Sumatra (Indonesia)✓ Correct Answer
    • B.Japan
    • C.California
    • D.Chile

    Explanation: A massive 9.1 magnitude earthquake off the coast of Sumatra triggered the 2004 tsunami.