# Height of Volcanoes

1. Dec 5, 2009

### hfenton

1. The problem statement, all variables and given/known data
Heights of volcanoes. You can assume that the density of basaltic magma is 2750 kgm-3, the density of lithospheric mantle is 3270 kgm-3, the density of oceanic crust is 2800 kgm-3, the density of seawater is 1030 kgm-3, and the depth of the ocean is 5 km.

A)What is the maximum height above the sea floor of an ocean island volcano fed by a magma chamber at the base of oceanic crust? Oceanic crust is typically ~7 km thick.

B)What is the maximum height above the sea floor of an ocean island volcano fed by a magma chamber at the base of oceanic lithosphere? Assume that the oceanic lithosphere is ~120 km thick.

2. Relevant equations

h = [(p(crust) - p( magma)) / p(magma)] * depth

3. The attempt at a solution

For A) [(2800-2750)/2750]*5000 = 90.91 m

For B) [(3270-2750)/2750]*5000 = 945.45 m

I don't think these are correct, because I don't know where I am supposed to use the density of sea water and the thickness of the oceanic crust and oceanic lithosphere. Any help would be greatly appreciated! Thanks!!