A fault has an Mw 8.5 earthquake roughly every 200 years. Imagine that scientists found a way to trigger Mw 5.0 earthquakes whenever they wanted. If they wanted to release the same amount of energy as the Mw 8.5 earthquake, how many of the smaller earthquakes would they need the same 200-year time period

340

Explanation:

Given that

The time period in question is 209 years

The magnitude of the first earthquake is 8.5 Mw

The magnitude if the artificially induced earthquake is 5.0 Mw

To solve this question, we'd use the simple relationship of

8.5 * 200 = 5.0 * Y, where

y is the no of artificial earthquakes required ..

Making y subject of the formula, we have

Y = 1700 / 5.0

Y = 340

Therefore, we have 340 smaller earthquakes in the said 200 yrs time period

they were chasing the bread.