Bricks, Masonry, Asphalt and Concrete - Removing fireplace hearth

We have a large brick hearth in front of our firelplace that is about 8" tall and extends about 2' into the room. It has also been tiled with granite tile. I am trying to remove the hearth without damaging the fireplace, so I can replace it with floor level tile.

My questions are does the hearth likely sit on subflooring or does it extend down through the crawlspace and to the ground. Also, will the bricks from the hearth likely tie into the vertical surface of the fireplace, or will they likely be separate, allowing me to leave the fireplace unscathed. What is the best way to do this?

Thanks.

All the hearths on my 4 fireplaces are part of the floor of the fireplace. It may be that you have to start disassembling and make it up as you go, being prepared to saw apart from the main fireplace.