Thunderous Bolt

As the casting begins a low humming starts and small lightning arcs dance across your body and connect with metal objects around you. When the casting ends all arcs move into your arcane focus as they charge it with immense power then a split moment later a unbelievably violent, ear shattering jolt of lightning flies through the air and connects with the poor victim. The target creature must make a Dexterity saving throw. The target takes 4d6 lighting damage on a failed save, or half as much on a successful one. All creatures smaller than huge in a 20ft radius must make a Strength saving throw. The creature takes 4d6 thunder damage and is knocked prone on a failed save. or half as much on a successful one and is not knocked prone. 

the jolt causes the earth to be scorched and any lose objects are knocked, 50 ft away 

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d6 lighting and thunder for each slot level above 4th.