The Upheaval

Earthquakes are fairly rare on Thaiterra, and particularly in the region of the Agaridian Plains. This simple fact is part of what made the Upheaval event so devastating.
None of the three dominant species that inhabited that area were prepared to deal with this particular cataclysm. The Garruw found their mountain homes turn into crushing tombs in some cases, as families tried to frantically dig out loved ones. The Weinadi saw the whole texture of their chasm and valleys change and shift, although the more transient nature of their lives at the time served them well as the majority of their constructions were more flexible in nature.
The ones who lost the most were those in the Dome, when part of their protective shell was destroyed in the quake. The buildings within meant as a last line of defense were cracked and unsafe, and a vital link to their past was lost.

Manifestation

Poetically, the earthquake was described as though the earth itself had cracked asunder. The event in general was very brief, lasting only a minute and scarcely more than that. There were no warning signs beforehand, no storms in the sky (an unusual event in itself).
In the aftermath, the chasm home of the Weinadi was nearly destroyed, with the stone walls having compressed almost half a meter in measurable terms. Smoke filled the sky, and dust from the rubble of fallen things.
The most vivid visual described is the splintering of the Dome. The great panels that compose the shell were cracked, and in some places missing entirely. Within was chaos. People struggled to find an enclosure to protect them from the toxic air in time to survive, which was no longer an easy task thanks to the damage.

Localization

The Upheaval happened in the Agaridian Plains.

Type

Metaphysical, Elemental