Eruption

You create a seismic disturbance at a point on the ground that you can see within range causing a huge eruption of lava and molten rock. For the duration, an intense tremor rips through the ground in a 75-foot-radius circle cantered on that point and shakes creatures and structures in contact with the ground in that area.

The ground in the area becomes difficult terrain. Each creature on the ground that is concentrating must make a Constitution saving throw. On a failed save, the creature's concentration is broken.

When you cast this spell and at the end of each turn you spend concentrating on it, each creature on the ground in the area must make a Dexterity saving throw. On a failed save, the creature is knocked prone.

The spell will cause a 20 foot circle pool of lava in the middle of the effected area, any creature that fails the dexterity save  in this area will fall into the lava and will take 4d10 fire damage, this damage shall repeat at the end of every turn the creature spends in the lava. This damage also extends 15 feet beyond the edge of the lava. At the end of every turn the creature must make a Constitution save or take the full fire damage or half damage on a successful save.

The eruption also causes 1d4 number of volcanic fissures to open up, the caster can choose where the fissures are created under the following conditions; the fissures must start at the edge of the central pool of lava and be no longer than 30 feet long and they are 10 feet wide. These fissures also deal damage to creatures and structures 10 feet either side of them. At the end of every turn the creature must make a Constitution save or take the full fire damage or half damage on a successful save.

If a creature that is where either the lava pool or the volcanic fissures will appear and they succeed the dexterity saving throw they will be placed on the edge of the lava. The lava is counted as difficult terrain.