Starting on August 10, 1944, the 7th Air Force B-24 Liberators bombed the airfields and troops on Iwo Jima continuously up to the invasion. The goal was not necessarily to bomb the Japanese forces on Iwo Jima into submission, but to disrupt and neutralize the Japanese ability to strike American airfields in the Marianas from Iwo Jima.

Above is a nice photo of a 392nd Bomb Squadron, 30th Bomb Group Consolidated B-24J Liberator after its bomb run with Mount Suribachi in the background. Note the Japanese use of smoke pots in an attempt to obscure the location of the airfields from the bombers. The photo below shows a 42nd Bomb Squadron, 11th Bomb Group B-24J Liberator on its way back to the Marianas after bombing Iwo Jima.

While the 7th Air Force B-24 crews were very accurate in placing their bombs within the target areas, it did not take very long for the Japanese forces to repair the bomb cratered runaways to get the airfields back in service.

Reference:

Strike and Return: American Air Power and the Fight for Iwo Jima, Cory Graff, Specialty Press (2006)