» Wed Aug 26, 2009 12:26 pm
First, the amount of force needed to trigger a volcanic eruption is "variable": if the volcano is close to erupting anyway, a relatively small shock could set the events in motion; if it's not near that stage, then a HUGE amount of force would be required. The fall of Baar Dau onto Vivic would be a "small" shock in geological terms, but still sufficient to destroy the city and send shock waves and flooding over a wide area, ESPECIALLY if its original momentum was merely being "contained". It might or might not trigger an inactive volcano nearby, but it might trigger other more sensitive earthquake and volcano sites elsewhere.
A true "dinosaur killer" meteorite would cause the planet to "ring" from the impact, and trigger a series of earthquakes and volcanos worldwide. That additional smoke and ash, in addition to the original plume of debris (and searing waves of steam scouring the nearby land, in the case of a "water strike"), would cause a "global winter" effect, causing the failure of the food chain worldwide, and the mass extinction of both many plant and animal species around the globe. In that case, either TES V or FO4 could take place in Cyrodiil. We won't need to visit Skyrim, because that would turn to nothing but the "snow and ice" that everyone says it's not, at least until the world recovered. Few of the Nords would survive for long, either, aside from those in the most southern areas or abroad at the time.
Baar Dau was largely hollowed out for use by the Ordinators, but if much of its mass was used for building materials, one might wonder if those also resumed their original velocity and caused smaller catastrophies wherever they were used, all of it still adding to the overall force of impact. Vivec's interruption of the moon's fall was originally done at the height of his power, relatively fresh after taking power from the "Heart", and it was probably more and more of a drain to maintain it as that power faded. Whatever happened after he was seized and taken to Oblivion, at some point that power was no longer sufficient to contain the pent up energy of the fall.
Much of this was "foreshadowed" in the lore, so the fall of the moon wasn't so much a "surprise" as an "I didn't think it would cause that much damage when it happened" event. Parts of Morrowind were buried under nearly 200 FEET of ash after the eruption of Red Mountain at the fall of the Dwemer, according to the one in-game book on Dwemer ruins, so this isn't the first time the province has been "destroyed". It will eventually recover, but certainly not in a few decades, and it's not likely to regain any sort of "significance" for several centuries at the least. At least it won't be another generic "happy forest", like Cyrodiil was depicted, if the developers ever decide to place another game there 100-200 years further down the timeline.