Advantage to farmimg of a flat land

If there were a landslide the plants wouldn't be uprooted or taken away by masses of moving dirt.

Farms were  established  on level area since it is the most fruitful and the least demanding to cultivate. Level area is less powerless to water disintegration. It is the least demanding to inundate if necessary. Level area is by all account not the only land that is cultivated, however, by any methods, by and large slopes are the main area accessible to cultivate, and in different cases, inclining area is favored. For plantations and vineyards sloping area is better since cool air, similar to water, streams down slope since it is heavier than warm air. In cases like early Spring or late Fall ices, being on a slope can spare the product, where on level area you may free it. The level and tenderly slanting area is better for grain and vegetable yields. Were bumpy area is utilized for field and to raise domesticated animals.

Magma is outside the volcano  and lava is inside the volcano. 

I'm pretty sure it's c. extremely gradual but not 100% sure though.