The Big One: Be an Earthquake Detective

Search “Cascadia” and open the page called “The big one.” Read the whole page, then answer each question. You only need this one page.

1. 1.About how far off our coast is the place where one slab of the Earth is sliding under another?

   🔎 The opening paragraph.

2. 2.What is the name of the long fault that runs offshore near us?

   🔎 “A fault the length of the coast.”

3. 3.How big (what magnitude) can this kind of “megathrust” earthquake reach?

   🔎 End of “A fault the length of the coast.”

4. 4.On what exact date do scientists say the last great Cascadia earthquake happened?

   🔎 The heading about January 26, 1700.

5. 5.What are “ghost forests,” and what happened to make them?

   🔎 The “Ghost forests” clue card.

6. 6.Name the three kinds of evidence that point to the same night.

   🔎 The three clue cards in “How we know it happened.”

7. 7.When the ground shakes, what three things should you do?

   🔎 The bullet list under “We can’t predict it — but we can be ready.”

Challenge · Grades 7–12

1. 8.A tsunami flooded Japan but no one there felt an earthquake. Explain how that “orphan” wave helps prove the date of a quake across the ocean here.

   🔎 The “A tsunami with no earthquake” card + the “nine-hour trip” paragraph.

2. 9.No one can predict when the next quake comes. So why does it still make sense to practice drills and know a plan?

   🔎 “We can’t predict it — but we can be ready.”

3. 10.At the coast, why does the page tell you to move to high ground on your own instead of waiting for an official tsunami warning?

   🔎 The second preparedness bullet.