I'm guessing that the answer is droughts? i'm not really sure...
Answer: Volcanic eruptions occur only in certain places and do not occur randomly. This is because the Earth's crust is broken into a series of slabs known as tectonic plates. These plates are rigid, but they “float” on a hotter, softer layer in the Earth's interior.
Explanation:
Plates move because of the molten rock in the mantle.
The syncline is actually part of the younger layers
The anticline would be the oldest layer at the fold