2007-02-05 10:48:37 · 4 answers · asked by abuamin55 2 in Science & Mathematics ➔ Physics
We know by determining the different densities of the inner earth, which allows us to calculate its composition. This is done by recording when earthquakes occur on one side of the world, and monitoring when that earthquake's shock waves reach different parts of the globe. When a shock wave is traveling through the earth and it reaches the less dense molten layer, it speeds up, and is skewed from its normal path. By taking hundreds of reading all over the world we begin to see a sort of picture of the inner earth. The shock waves act like sonar, and allow us to calculate relatively accurately what is beneath the crust.
2007-02-05 11:06:32 · answer #1 · answered by Donatello 1 · 0⤊ 0⤋
We can send shockwaves down through the earth, whenever there is an interface (crust - mantle) some of it will reflect back. The time it takes to do this can tell us the depth.
2007-02-05 11:00:41 · answer #2 · answered by teamuni 3 · 0⤊ 0⤋
from the depths of the oceans
2007-02-05 10:51:09 · answer #3 · answered by sunflare63 7 · 0⤊ 0⤋
magnetic scanners and sizemographs(sp?)
2007-02-05 10:51:57 · answer #4 · answered by Anonymous · 0⤊ 0⤋