dice are d600, roll low to hit/crit/effect, roll high for multi hit
Step 1:

earthquake
-3 en
8 crit yes
(10 + 8 + 3 - 7) * 1.5 = 21 damage

surf
-3 en
84 crit no
(9 + 7 - 5 - 1) * 1.5 = 15 damage
weak pol proc, +2 atk, +2 spA (4t)
Step 2:

earthquake
-3 en
12 crit no
(10 + 8 - 7) * 1.5 + 8 = 25 damage

surf
-3 en
159crit no
(9 + 7 - 5 - 1) * 1.5 = 15 damage
Step 3:

earthquake
-3 en
254 crit no
(10 + 8 - 7) * 1.5 + 8 = 25 damage

faints!