I'm of the opinion we just need to wait for DH to return and address this as this is an advanced python matter to resolve and he's been working on it already so has a good idea of what needs to be done.
Additionally, as more events are designed for the eras where these volcanoes are deemed 'too frequent' we'll see them happen less to make room for those new events. So if you'd like, feel free to start envisioning some new events for design and you might also want to pitch in and learn how to make them so you can help us put those new events into the game. Ori, our events guy, is pretty busy and could use some help in that dept. Furthermore, events are one of the easier things to learn how to do as there are some good tutorials on the subject on CivFanatics forums.
However, just to clarify, you ARE seeing volcanic events YOU are causing. This only means that every player is checked for a possible event every round, then runs through the events that CAN happen thanks to all the filter qualifications on those events, and its YOU this time that triggered a volcano event (largely because there's no cause for volcanic events to be unable to come up in your selection list, no filters you may have to keep it from happening while most other available events you may not be qualifying for leaving only the volcanic event options available). '
Since a volcanic event can happen anywhere in the world once triggered by ANY player, you'll be notified, inappropriately, of a Volcanic event taking place even where you can't see it, and denied notification of some Volcanic events taking place where you can (triggered by other Civs on their turns). This messaging problem is exactly what DH is trying to fix but was interrupted by RL for a bit.
But the Wall lives here too (" you can't have your pudding if you don't eat your meat"). 
