Tidally Locked Moons

Both of the moons of Tellus , Luna and Terra, are tidally locked to the planet. This in turn has caused what some of the professors at the colleges call 'the curiosity factor'. Indeed, many of the doctoral dissertations that come out of that bastion of higher learning known as The Bardic College Campus have to do with this precise issue. Forces and geological repurcustions have been measured in minute detail; an entire body of work on the subject being compiled by the College of Astrophysics at the Campus.
One of the effects on Tellus that needs more study is that of its obvious stimulation of vulcanism in the The Warmwind Sea. In a nine year cycle, several of the volcanoes located within the ancient boundaries of The Tolmec Empire begin to erupt with impressive regularity. While the phenomenon has been noted, and even measured to some extent, the implications of this anomaly have yet to be thoroughly explored.
Since the discovery, in 5427NG, that Luna is (in fact) a construct of some kind, a massive structure that had carried refugees here from a far off place, the collective curiosity has been piqued. Being, essentially, hollow, the gravitational forces Luna exerts upon Tellus should be quite small, yet it has at keast twice the pull of its sister, Terra, leading to a whole lot of head scratching, and a full-on revolt against mathematics professor Gnarles Gnommenclature. The professor was proven out in a mater of two short years, yet by that time the brilliant and beautiful mind of Gnarles Gnommenclature had taken themselves out into the frontier to run an inn on the west coast of Pax, where there is no math lab for a thousand miles.

Manifestation

Several, to a few dozen, of the volcanoes making up the archipelagoes within the ancient bounds of The Tolmec Empire begin to erupt on a nine year cycle. These can be everything from spectacular explosions to seeping lava flows, but they come every nine years on the dot, and they stay for nine months, nine days, ninety minutes, and twenty two seconds.

Localization

The eruptions, with a very few exceptions, happen only in The Warmwind Sea.

Type

Natural