How much energy released in an earthquake of magnitude 8

Richter scale's intensities range from 0 to 9. They're measured according to the formula

i= ⅔ log₁₀(E/Eo)

i stands for intensity
E is the earthquake's energy
Eo=7*10⁻³ kWh

How much energy is released in an earthquake of magnitude 8?

i = ⅔ log₁₀(E/Eo)
Eo = 7*10⁻³ kWh
i = 8

so: 8 = ⅔ log₁₀(E/7*10⁻³)

Now, solve for E

12 = log₁₀(E/7*10⁻³)

You undo log base ten by taking 10 to the power of both sides:

10^12 = 10^[log₁₀(E/7*10⁻³)]

10^12 = E/7*10⁻³

E = (10^12)(7*10⁻³)

E = 7,000,000,000 kWh

Given that,
8=2/3*log(E/7*10^-3)
=> 12 = log E - log (7*10^-3)
=> 12 = log E - (-2.1549)
=> log E = 9.8451
So, E= 10^9.8451 = 7000031591.3089