The Traction Codex/Illustrated World of Mortal Engines said:
Slow Bombs Asteroids boosted onto Earth-impact trajectories during the Sixty Minute War, these massive weapons began to arrive over the decades following the conflict, like latecomers to a particularly rowdy party. They gouged great craters in the planet’s already battered crust, and the ash and debris they threw up contributed to the long period of global cooling known as The Black Centuries. Several Slow Bombs are said to have struck North America and one, perhaps a near-miss, obliterated the Isthmus of Panama, creating the Crater Sea.
After the 60 Minute War, multiple Slow Bombs hit the Earth, one of which destroys Panama, seperating North and South America. A quick search reveals that Panama has a
surface area of 75,517 km^2, or 75517000000m^2. It also has an
average elevation of 360m.
V = Ah
= 75517000000 X 360
= 2.718612e13m^3
For a low end we'll go with violent fragmentation (69000000 joules/m^3) and for a high end pulverization (200000000 joules/m^3).
(Low end)
E = 2.718612e13 X 69000000
= 1.8758422800000001e+21 joules
= 448.33706500956026275 gigatons
(High end)
E = 2.718612e13 X 200000000
= 5.437224e21 joules
= 1.2995277246653920145 teratons
Final Results
Slow Bomb destroys Panama (low end) = 448.337 gigatons
Slow Bomb destroys Panama (high end) = 1.29 teratons
