(SUPER LOW BALL) 1.8 gigatons, Large Mountain Level / High 7-A.
This is a very very low end calculation.
To get the 1.8 gigaton result the following assumptions were made:
- a medium sized Japanese oak (10 meters) for a reference for the size of the mountain/hill it crushed
- a 60 second timeframe
- 2,000 km travel distance from middle satellite orbit to sea level
- 50% hollowness.
(REALISTICALLY) Island level / 6-C at a minimum, Country level / 6-B at a maximum.
- If you highball the hill and say it's a mountain but change no other numbers, it becomes 436 gigatons (island level).
- If you highball the distance to space (you need to be 17,000 km away to see the full circumference of the earth at the equator), it becomes island level as well.
- If you lower the time frame to 30 seconds, island level again.
- Just counting it as 100% solid makes it Large Mountain+.
If you highball all four of these... the results will be more or less
837,128,990.3 x 7,850 = 3.28 x 10^12 kilograms x 566,666^2 meters per second x 0.5 KE reduction =
(SUPER HIGH BALL) 252 teratons, Large Country level / High 6-B.