In Fairy Tail: 100 Year Quest Chapter 18, Mercphobia moves a bunch of the Ocean from the Horizon to a town. Horizon distance will be assumed as 20 Kilometers.
First we need to find out the volume of the water moved.
Photo 1:
Average Mountain Height = 609 Meters = 11 px
609 Meters/11 px = 55.36 Meters per px
Width of Water Moved = 1022 px = 56581.64 Meters
So since water was moved from the horizon to the point in town, the length of water moved is 20000 Meters
The average depth of the ocean is 3701.49 Meters, so I'll assume that as the height of the water moved
So the total volume of water moved is...
Volume = (56581.64)*(3701.49)*(20000) = 4.1887275e+12 Meters^3
The mass of water is 1000 kg/m^3
So the mass of the water moved is 4.1887275e+12*1000 = 4.1887275e+15 kg
Photo 2:
The distance it moved was a diagonal, I'll assume the center moved from halfway to the horizon to where Mercphobia is, so essentially point A moved to point C, so the length moved is 10000 Meters, but we need to find the height. First of all, the base of the water was moved from the bottom of the ocean floor to above the town, so we essentially need to find the height distance from point B to point D the ocean moved from an initial depth of 3701.49 Meters to above Mercphobia
Photo 3:
Average Human Height = 1.7 Meters = 32 px
1.7 Meters/32 px = 0.053 Meters per px
Height of Water = 808 px = 42.925 Meters
So the total height the Water was moved was 3744.415 Meters
So the total diagonal distance the water moved based off of Hypotenuse is 10678.04 Meters
The moved was done extremely fast, only a few small panels, so I'll assume a timeframe of 10 seconds, so we now calculate speed
Speed = 10678.04 Meters/10 Seconds = 1067.804 m/s
So now we can calc the KE
KE = 0.5*M*V^2
KE = (0.5)*(4.1887275e+15 kg)*(1067.804 m/s^2) = 2.3880048e+21 Joules = 570.75 Gigatons (Large Island level+)
This feat was performed casually by a Mercphobia who wasn't even at half his strength, so his full power would be 1.14 Teratons (Small Country level), which is extremely consistent and a good supporting feat.