Melee Splash Support will not add any tags. Neither does Arcane Surge. No supports add tags.

Melee Splash Support will add splash damage to a strike skill, which is area damage. Since the strike then has the property of dealing area damage, it would become suportable by Pulverise Support. That has nothing to do with tags.

Puverise Support's damage bonus only affects area damage. The splash is area damage, the direct hit that causes the splash is not. So that modifier only applies to the splash damage.

Because Glacial Hammer has a threshold jewel that adds an area component, it is always supportable by Pulverise supports that apply to skills with area. This is because threshold jewels being added and removed can't change supportability of gems, so gems get the necessary supportability by default.

EchoLocation8

Can you clarify for me:

• When you say that Glacial Hammer can be supported by Pulverise, does it actually benefit from it? The gem just says it supports melee attack skills, to me this implies Double Strike or something could be marked as being "supported" by it but with no meaningful gains.
• Does that mean Glacial Hammer by default is also buffable by Blood and Sand? If not, how does Blood and Sand interact when you do have the threshold jewel for Glacial Hammer in and/or affected by Melee Splash?

When you say that Glacial Hammer can be supported by Pulverise, does it actually benefit from it? The gem just says it supports melee attack skills, to me this implies Double Strike or something could be marked as being "supported" by it but with no meaningful gains.

That was a poor example. I meant to point out that Glacial Hammer is always supportable by supports that only apply to skills with an area component (such as Increased Area of Effect Support). Pulverise does not actually have this restriction, so that doesn't apply here. Regardless, any area-specific modifiers won't apply to a skill that doesn't have any area.

Does that mean Glacial Hammer by default is also buffable by Blood and Sand?

No. This is only about supportability, not about what has an effect.

If not, how does Blood and Sand interact when you do have the threshold jewel for Glacial Hammer in and/or affected by Melee Splash?

If you give Glacial Hammer a splash effect, then that's an area effect and area modifiers will apply to it. The non-splash hits are still not area damage and will still not be modified by area-specific modifiers.