How hazards and resources shaped where people live

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Use this

   A world map marking the Ring of Fire and the Nile and Mississippi floodplains.

2. 1.

   Why have river floodplains drawn farms and towns, by Ari's reading (USGS)?

   • Flood sediment leaves mineral-rich soil that makes excellent farmland
   • Rivers carry the soil away, leaving flat bare rock
   • Floods stop once towns are built on the plain
   • Floodplain soil is thin and rocky, so it is easy to dig
3. 2.

   Besides fertile soil, what else do river valleys offer people, by Bo's reading (USGS)?

   • Water, and routes for boats, roads and railroads
   • Deep beds of fresh volcanic soil
   • Cooler weather with no rain or floods in any season
   • Shelter from each kind of natural hazard
4. 3.

   Why do people farm the slopes of some volcanoes, by Kira's reading (USGS)?

   • Volcanoes stop erupting once farms are planted
   • Volcanic rock weathers into some of Earth's most fertile soils
   • Volcanic slopes get no rain, so crops stay dry
   • Fresh lava rock is soft enough to plow
5. 4.

   Where do most earthquakes and volcanic eruptions happen, by Jun's reading (USGS)?

   • Mostly near the North and South Poles
   • Along plate boundaries, like the Ring of Fire
   • Mostly in the middle of plates, far from their edges
   • At random spots anywhere on Earth
6. 5.

   About how many potentially active volcanoes are there worldwide, not counting mid-ocean ridges, by Luz's reading (USGS)?

   • About 135,000
   • About 1,350
   • About 17
   • About 13

7. Model sites (model data)

   Site	Soil	Fresh water	Transport	Main hazard
   A: river floodplain	rich river soil	river	river and rail	floods
   B: volcano slope	rich volcanic soil	springs	one road	eruptions
   C: coast	sandy soil	wells	port	storm surge
   D: dry plateau	thin soil	little	few roads	drought

8. 6.

   Using the model table, which site has river water and rail but faces floods, by Noah's reading?

   • Site C, the coast
   • Site A, the river floodplain
   • Site D, the dry plateau
   • Site B, the volcano slope
9. 7.

   Using the model table, what is site B's main hazard, by Pia's reading?

   • Eruptions
   • Drought
   • Storm surge
   • Floods
10. 8.

    Using the model table, which site has the least fresh water, by Ren's reading?

    • Site B, the volcano slope
    • Site C, the coast
    • Site D, the dry plateau
    • Site A, the river floodplain
12. 9.

    What does a 100-year flood mean, by Tala's reading (USGS)?

    • A flood that can't happen two years in a row
    • A flood that comes once each 100 years, on schedule
    • A flood that covers 100 miles of river
    • A flood with a 1% chance of happening in any year
13. 10.

    USGS: a 100-year flood has a 1% yearly chance. By the same rule, what yearly chance does a 500-year flood have, by Esme's math?

    Use the picture in question 9.

    • 0.2%
    • 5%
    • 2%
    • 0.5%