The answer is - lithosphere-atmosphere interaction.
The material that the volcano releases, rock, ash, and dust particles, and shoots them up in the air, is a material that comes from the inside of our planet, thus from the lithosphere. Since the material goes up in the air, and the air is part of the atmosphere, it means that material from one of the spheres goes to another sphere, in this case, we have an interaction between the lithosphere and the atmosphere.
