Explain why the southeastern islands in the hawaiian island chain contain active volcanoes and are larger while the northeastern islands are older smaller and have extinct volcanoes

This is happening because of the plate tectonics. The Pacific Plate is moving a few centimeters in a direction of northwest each year. There is a hot spot under the Pacific plate that keeps creating the islands, new islands are being formed in the southeast as the plates move, at the older islands in the northwest are being gradually destroying away.

Plate tectonics

Explanation:

Pacific plate moves in a few centimes every year in a northwestward direction and thus there is a hot spot under the pacific plate and this creates on an island and feeds more islands in the southeast while that of the old northwest are eroded.