PencilGo

Grade 9 · Science · Earth and Space Science

9th grade How earthquake waves reveal Earth's interior worksheet

6 printable versionsOn Level10 questions · answer keyFree · no account

Level: Building Confidence · On Level · Challenge Me

When it’s done, scan the sheet with your phone and PencilGo marks it and picks the next one. Create a free account

Version
Print

How earthquake waves reveal Earth's interior

Grade 9 Science Worksheet

NameDate

Circle the best answer.

  1. Read this first

    Model speeds

    WaveSpeed
    P6 km/s
    S3.5 km/s

  2. With model speeds P 6 km/s and S 3.5 km/s, how long is the S-minus-P lag at 210 km, by Bo's math?

    • 60 seconds
    • 95 seconds
    • 35 seconds
    • 25 seconds

  3. Table, Model lag table, with columns Lag, Distance

    10 s, 84 km; 25 s, 210 km; 50 s, 420 km. Note: model speeds P 6 km/s, S 3.5 km/s.

  4. A station's lag is 50 s. Using the model lag table, about how far away is the quake, by Esme's reading?

    • About 210 km
    • About 84 km
    • About 50 km
    • About 420 km

  5. Three stations with circles around them. Three stations each find their distance to one quake. How is the epicenter found, by Jun's reading (USGS)?

    • Draw a circle of that radius around each station; they meet at the epicenter
    • Use the first station by itself
    • Pick the station with the largest lag
    • Average the three distances

  6. From mantle to core, wave speed drops about 30% (USGS). A model P wave at 10 km/s just above the core would travel about how fast just below, by Luz's math?

    • About 10 km/s, unchanged
    • About 3 km/s
    • About 7 km/s
    • About 13 km/s

  7. Why do earthquake wave paths curve inside Earth, by Milo's reading (USGS)?

    • Rock at different depths changes the waves' speed
    • Waves follow straight lines at one speed
    • Earth's spin bends them
    • The Moon's pull bends them

  8. Use this

    Earth cutaway with a shaded band.

  9. Station 1 sits 60° from a quake, station 2 at 120° and station 3 at 150°. Which one sits in the P-wave shadow zone, by Noah's reading (USGS)?

    • Station 3, at 150°
    • Station 2, at 120°
    • Stations 2 and 3
    • Station 1, at 60°

  10. Of those stations at 60°, 120° and 150°, which records direct S waves, by Pia's reading (USGS)?

    • Stations 1 and 3
    • Station 3, at 150°
    • Station 2, at 120°
    • Station 1, at 60°

  11. Oldham identified Earth's core from earthquake records in 1906 (USGS). Which observation shows the outer core is liquid, by Ren's reading?

    • Its P waves speed up sharply
    • It does not transmit S waves, and P waves slow sharply
    • It transmits S waves faster than the mantle
    • Its waves arrive before the P waves

  12. Data on the Earth's interior (USGS)

    LayerThickness
    crust30 km
    upper mantle720 km
    lower mantle2,171 km
    outer core2,259 km
    inner core1,221 km

  13. Using the USGS thicknesses, how deep is the top of the outer core, by Tala's math?

    • About 750 km
    • About 5,180 km
    • About 2,171 km
    • About 2,921 km

  14. A drill hole on the Kola Peninsula reached 12 km (USGS). About what share of the 6,401 km to Earth's center is that, by Ari's math?

    • About 0.2%
    • About 2%
    • About 20%
    • About 12%
PencilGopencilgo.com

9th grade How earthquake waves reveal Earth's interior worksheet – printable
Print: 123456

About this worksheet

Use earthquake waves to find Earth's layers. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can tell P waves (first, squeeze rock, cross liquids) from S waves (slower, shake sideways, stop at liquids).
  • I can use the S-minus-P lag to find a distance, and arcs from several stations to find an epicenter.
  • I can explain how the shadow zone and speed changes show a liquid outer core, a solid inner core and the Moho.

Standard: HS-ESS2-3

Words to know

P wave: The first-arriving wave; it squeezes and stretches rock

S wave: A slower wave that shakes rock sideways; it stops at liquids

S-minus-P lag: The time between the P and S arrivals; it grows with distance

shadow zone: 104° to 140° from a quake, where no direct P waves arrive

Moho: The crust-mantle boundary, where wave speed jumps up

Common mistakes

Your child swapped P and S waves. USGS: the P wave squeezes and stretches rock and arrives first; the S wave shakes rock sideways at a bit over half the P-wave speed.

Your child sent S waves through a liquid. USGS: the outer core does not transmit S waves, which is why scientists call it liquid.

Your child misused the S-minus-P lag. The lag grows with distance; subtract P time from S time, then read the distance, and use several stations to find the spot.

Questions parents ask

What is the most common mistake with how earthquake waves reveal earth's interior?

Your child swapped P and S waves. USGS: the P wave squeezes and stretches rock and arrives first; the S wave shakes rock sideways at a bit over half the P-wave speed.

Are these 9th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

More earth and space science

See all Earth and Space Science

Every sheet you scan goes into your child’s record: dated, marked and ready for the year-end portfolio. Homeschool records

Ready for easier practice?

Print a sheet, scan it when it’s done, and PencilGo picks the next one.

Create a free account