An earthquake of m8 causes the amplitude of ground motion to be times larger than a m7 earthquake and times larger than a m6 earthquake.

10, 100

Explanation:

Magnitudes are based on a logarithmic scale (base 10). For each whole number you go up, the amplitude of the ground motion recorded by a seismograph goes up ten times. Using this scale, a magnitude 5 earthquake would result in ten times the level of ground shaking as a magnitude 4 earthquake (and 32 times as much energy would be released).

1 unit increase corresponds to 10 fold increase in magnitude.

they use tree rings to figure out weather patters.

the only other powers were germany russia and uk and they were too busy fighting each other wearing each other down   that the us was becoming strong and they were becoming weaker