I cant say much about the humming noise, but the deformation of the planet is mainly caused by the Moon's gravitation. Same as it pulls on the water of the oceans, it also pulls on the Earth's crust. And the Sun does, too, to a lesser extent.
And then there is the rotating liquid metal core in the center of the earth, and the convection movement of the magma, the plate tectonic and the movement of the atmosphere. Those are all incredibly powerful forces, that could well cause vibrations and therefor noise.