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.

the correct answer would be true friction causes the faults to slip or collide