Thread: How was Mauna Kea measured to the ocean floor?

I see where Mauna Kea is considered the tallest mountain in the world because it's measured from its peak to its base on the ocean floor.

I wondering exactly how this measurement was done. How did they determine the exact spot where the mountain ends at its most distant point from the peak on the ocean floor? It must be an exact spot too because the official height is listed down to the foot (33,476 ft.)

Any replies will be very much appreciated!

i've been reliably informed that the calculations were performed on the back of a fag packet, the sole purpose of the exercise being to be able to say that the largest mountain on earth lies in the US of A

I suspect, but do not know, that there is a nominal depth for an 'average' surface of the abyssal plain, from which Mauna Kea rises. That would have been determined by echo sounding over many points. Alternatively the edge of the earliest lava flows making up the base of the volcano have been identified with remote submersibles and the depth/height computed from this. However, the precision of the measurement makes me uncomfortable as it implies they have a precise fix to within feet of the base level. I doubt that - though I would not be gobsmacked if someone showed me how it was done. (But it would have to involve a nominal decision to call this the base level rather than that. So Marnix's scenario is not all that removed from the truth.)

Everest is taller if you measure it from its peak to the ocean floor. Seems a bit unfair to judge the two from different benchmarks eh? I suspect Marnix is on to something there.

Originally Posted by ebc123

I see where Mauna Kea is considered the tallest mountain in the world because it's measured from its peak to its base on the ocean floor.

I wondering exactly how this measurement was done. How did they determine the exact spot where the mountain ends at its most distant point from the peak on the ocean floor? It must be an exact spot too because the official height is listed down to the foot (33,476 ft.)

Any replies will be very much appreciated!

Well Echo Sounding I think is the highly probable answer, and yes, all mountains are measured from their base for height. You also see "above sea level" but from the base is the correct method.