# How much would the ground shake under King Kong?

I needed a creature about 50 feet tall and King Kong from the 1976 movies fits the bill. According to sources he is 50 feet tall and weighs 7 tons (I raise a large eyebrow at that, but it is all I got). If you want seen that version, he is completely bipedal. How many vibrations would a human feel and from how far from Kong walking?

## Trembling at 30-40 meters, King Kong would jump up and down

>50 ton pile drivers for comparison

I've lived in a very busy building area in the Netherlands, for years in a row. Always building building.. mainly apartment buildings. they use Pile drivers into soil here, for nearly everything, also houses. . When I'd get near a Pile driver, the ground trembling would be noticable from about 150-200 meters distance. It would be audible from 1-2km distance. Clay soil, sand may be more moderate I would expect. Also near buildings would echo, there will be multiple instances of the boom.

https://en.wikipedia.org/wiki/Pile_driver

7 ton Gorilla makes a lot of noise, especially

So.. the pile driver thing is more than 50 tons. With KK, we're talking a gorilla weighing in about 7 tons. When King Kong would jump up and down and make noise on purpose, stamping the ground to get my attention, and we estimate the effects to be linear, you'd get trembling at 30-40 meters distance, audible from about 300-400 meters. Boom Boom.. in a city, with echo's everywhere, it will be spectacular sound. But when King Kong would do that on the middle of the street, I don't expect buildings to collapse, or windows to crack.

.. but he could sneak up on you also !

But I think you'll have to take into account King Kong is an animal. The purpose of walking and running around is to get moving, not to loose energy by stamping and making noise. I even suppose King Kong could sneak up on you and suddenly appear. It will depend on the surroundings (e.g. grass land) and on his intentions !

• +1 also given that a 150 cm person may mass around 40 kg it's probably more realistic for a 1500 cm gorilla to mass closer to 40,000 kg than 7,000 kg. Commented Mar 30, 2022 at 22:22
• @KerrAvon2055 In that case it would be comparable to the pile driver ! But also for here.. KK would really have to stamp the ground with all its weight, to be comparable to a pile driver action. Commented Mar 30, 2022 at 22:24
• Wouldn't the far larger size of his feet (compared to the striking area of a piledriver) mitigate that greatly? Commented Mar 31, 2022 at 13:52
• @TED you are right.. a pile driver will yield far more high frequency components with more energy as well. The material is steel on concrete. The sound of a stamping King Kong would be boom-boom, far lower frequency. But with 7-40 tons of weight, the amplitude (trembling) would still be considerable. Compare sounds of the dinosaurs in Spielberg's Jurassic Park.. Commented Mar 31, 2022 at 14:52
• How tall are the pile drivers you're describing? The weight of the object is only half the story, the amount of energy it releases is also dependent on how far it falls. I might expect a 50-ton pile driver to be quite a bit taller than Kong's vertical leap of perhaps 20-40 feet. I think the material also makes a big difference - hitting metal on rock can be very loud, releasing more vibrational energy than any sound you could produce by hitting the ground with part of your body. Commented Mar 31, 2022 at 14:54

none.

large animals take incredibly soft steps, an elephant walks silently for instance. if they are generating shock that shock is also being applied to them, which adds up to a large added stress on their bones and joints, so there is a decent evolutionary pressure for multi ton animals to walk silently even if you have no predators.

• Having ridden an elephant for a few hours on fairly hard ground (Zambia, hard-packed red earth), I definitely agree; it was pretty much silent and there was a pronounced (and pleasant) side-to-side sway but no appreciable vertical jolting. It was oddly like being in a boat on a light-to-moderate sea. The creature in question was an adult female African elephant, so probably weighed around 3,000kg. Commented Mar 31, 2022 at 9:55
• An elephant at normal walking pace, maybe. If an elephant was stampeding near you, you'd probably feel some ground shake. Commented Mar 31, 2022 at 13:41

## The same as a 7-tonne elephant: none

The largest elephants weigh almost 7 tonnes, and while I've never seen one quite this big, I've spent plenty of time around elephants in a zoo and in the wild.

I can tell you: they walk quietly. The loudest sound is the occasional snapping of branches underfoot, and there's absolutely no trembling of the ground.

Thanks to the square-cube law, a realistic King Kong would be restricted to walking like an elephant: on all fours and without jumping. Gorilla anatomy is sadly not designed to be scaled up to 50 feet tall.