What was the effect of Mt. Vesuvius on the Lithosphere?
Volcanoes typically don’t have much of an effect on the lithosphere, especially continental lithosphere with thickened crust due to continent/continent collisions. There is a possibility of the extra mass cracking the lithosphere, which is what some geoscientists think has happened with the Hawaiian Island volcanic chain in the Pacific Plate. However, that scenario is over relatively thin oceanic lithosphere due to the gravitational force exerted by massive volcanoes, and this situation doesn’t apply to Mt. Vesuvius. There is a possibility of some flexture due to Vesuvius, but I have not heard of any claims in that regard.