Tire Bubble problems of the 2007 Saturn ION

I noticed a vibration on my steering wheel. When I checked the tires I noticed a bubble (tire separation?) on the inside front passenger tire.

I have had 4 tire failures on my 1997 Saturn Ion. All tires were goodyear assurance 195/60/r15 tires. In ones instance, a tread separation occurred. In two instances, bubbles developed on the inside sidewall of a front tire. The fourth instance also had sidewall damage, but whether there was a bubble first is not know. This happened on 1/22/2010, 11/5/2008. 1/26/2009 and 7/16/2009, at 26,000, 29,000, 34,000 and 40,000 miles.