Calculation

[Peppypony]

so there's a moment in one of my stories where a robot makes a laser beam. i made a sketch of the scene and the explosion was 8km wide (so the diametre) and crater was 25 metres deep. the explosion expands to it's full size and then disappears, all in 1.36 seconds. there's no rubble or anything left in the crater, so let's assume it's disintegration. no it's not nuclear. i know the page here would say small city level, but i'm imagining it leaving behind a 50 metre deep crater as it hit the ground must make a difference tho. it was in the desert (think the sahara or the mojave) so the ground would've been sand and maybe sandstone.

 

[Peppypony]

1. i forgot that nuclear would still apply even if it’s not actually a nuclear explosion because it’s a nuclear effect.
2. the crater, the bottom is the crater is flat, it’s 50 metres deep and therefore it’s edge are 50 metre high walls

 

[Peppypony]

bump

 

[Rayfire]

Considering this is in a desert this was most likely sand that was being vaporized, so now we need to find the volume of the crater. Assuming it is perfectly 50 metres high, wide, and long like you say, this means 125,000,000,000 square centimetres of sand were obliterated.

Pulverisation seems to fit the mold best for this considering there is no rubble, and the value of which for sand is 1-1.2 J/cc according to the calculations page. This seems to be for low and high balls, so I’ll just do 2 calculations for both.

125,000,000,000 cm² * 1 is, well, 125 billion joules, or 29.87 tons of tnt.

125,000,000,000 cm² * 1.2 is 150 billion joules, or 35.85 tons of tnt

Both of which are City-Block Level.

If this is sandstone it would probably be much higher tho

 

[Peppypony]

No the crater is 50m deep but the explosion itself is 8km high and wide.

 

[Rayfire]

No the crater is 50m deep but the explosion itself is 8km high and wide.

Oh alr, lol

Well, adding the high-ball of this calc to the 8km explosion (Which is about 1.23x the baseline for city level according to explosion yields, or 7.74 megatons) wouldn't really change the potency much.

3.24218e+16 joules (8km explosion itself) + 1.5e+11 joules (Crater calc high-ball) = 3.242195e+16 Joules, or 7.749 Megatons (Assuming i am interpreting this correctly, lol)

 

[Peppypony]

Alrighty so slightly above baseline 7-B, cool thanks.