Measuring Earthquake Strength · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

How Strong Was That Earthquake?

Science · Volcanoes & Earthquakes · ages 9-11
Name ______________________   Date ____________

  1. A town far from a fault feels earthquake waves. What travelled from the fault to the town?

    • Energy carried by waves through the ground
    • All the rocks at the fault sliding into the town
    • The fault itself moving across the whole countryside

  2. Which pair of details belongs in a seismometer's ground-movement record?

    • When shaking happened and when the next quake will start
    • When shaking happened and how much the ground moved
    • How many people felt shaking and how frightened they were

  3. What tool do scientists use to detect and record ground shaking?

    • Thermometer
    • Seismometer
    • Barometer

  4. A bigger magnitude number describes a larger earthquake.

    Circle one:   True   False

  5. A seismometer stops recording halfway through an earthquake. What should scientists look for to study the shaking it missed?

    • Proof that the ground stayed still throughout the unrecorded time
    • A guessed record based only on the earthquake's reported magnitude
    • Complete records from instruments that kept working

  6. A report lists one earthquake at magnitude 4 and another at magnitude 6. Which earthquake was larger?

    Magnitude. Ticks: 0, 1, 2, 3, 4, 5, 6, 7, 8. Marked values: 4, 6. 012345678Magnitude
    • Magnitude 4
    • Magnitude 6
    • They were equally large

  7. How do seismometer records help scientists study an earthquake?

    • They help scientists estimate its magnitude
    • They list the names of everyone who felt shaking
    • They predict the exact date of the next earthquake

  8. A wave reaches one station 10 seconds after a quake starts and another at 16 seconds. How many seconds later does it reach the second station?

    Answer: ______________

  9. Jamal says a seismometer only records shaking that people can feel. Which reply fits the instrument's job?

    • People must feel the movement before it can be recorded
    • It can record movement too small for people to feel
    • It records people's reports instead of sensing movement

  10. A high-magnitude earthquake causes light shaking in a distant town. What does its high magnitude describe?

    • The strongest shaking felt at every distant location
    • The exact damage suffered by each building in that town
    • The overall size of the earthquake at its source
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Answer key

For grown-ups. Fold this page away before handing over the rest.

How Strong Was That Earthquake? W1-mt_mdZ3nBWChW-s1

  1. Energy carried by waves through the ground · Waves carry energy. The rocks at the fault do not travel with them to the town.
  2. When shaking happened and how much the ground moved · The record includes the time of movement and how much the ground moved.
  3. Seismometer · A seismometer senses shaking in the ground and records it.
  4. True · Higher magnitude describes a larger earthquake, related to more energy released.
  5. Complete records from instruments that kept working · The failed recorder missed information. Working instruments may provide records covering the missing time.
  6. Magnitude 6 · Magnitude 6 is higher than magnitude 4, so it describes the larger earthquake.
  7. They help scientists estimate its magnitude · Ground-movement records help scientists estimate an earthquake's magnitude.
  8. 6 · Subtract the earlier arrival time from the later time: 16 - 10 = 6 seconds.
  9. It can record movement too small for people to feel · A seismometer can sense and record ground movement too small for people to feel.
  10. The overall size of the earthquake at its source · Magnitude describes the whole earthquake. Local shaking can be weaker.
Worksheet · LightMySky