this hit pretty late but looking back at this
asteroid feat wouldn't we be able to potentially yield higher results if we used the kinetic energy of this moving fast enough to catch fire which should be comparable to these speeds stated in this
jojo's calc and to make a rough calc of this
as found from my own
calc this asteroid has a volume of 1570688.98887 cm³ and the density of iron is 7.874 g/cm³ so that means 7.874 * 1570688.98887=12367605.0984 grams or 12367.6050984 kgs
since KE = 1/2 * mass * velocity^2 so that would mean 1/2 * 12367.6050984 * 17000^2 = 1.7871189e+12 joules or 427.13 tons of tnt
Multi-City Block I'd probably have to find feats that escape the small building tier in order to have this applied however