Why acceleration due to gravity decreases under Earth's surface ?
Kindly refer the similar link below.
https://www.meritnation.com/ask-answer/question/how-does-the-acceleration-due-to-gravity-decreases-as-one-g/gravitation/3094605
https://www.meritnation.com/ask-answer/question/how-does-the-acceleration-due-to-gravity-decreases-as-one-g/gravitation/3094605