MANHATTAN - A memorial service Thursday morning commemorated the one year anniversary of a deadly gas explosion in East Harlem. 

The blast leveled two buildings, killed eight and injured more than 60 people. 

A moment of silence was held at 9:31 a.m., the exact time the tragedy took place. 

Officials believe the explosion resulted from a leak in a 127-year-old gas main, but investigators have not yet issued a final determination on the cause.