IPhone 4G, how do I stop the alarm from vibrating during the sound?

IPhone 4G, how do I stop the alarm from vibrating during the sound?
Added (1). I have an iPhone 4G for which I have lost the manual (of course). I use the phone to wake me up every workday morning, and it plays a different song each day. However, it also vibrates this loud, jarring buzz that rattles horribly on my nightstand, freaks out my sleeping cats, and starts my day off on a sour note.
Added (2). I can't find anything in the Settings or Clock that would remove the vibration and buzzing and just let the song play. The only I can think of is this might be "Airplane Mode"? I've no idea what that is. Anyway, does someone know how to stop the buzzing vibrations? Erm… No snarky comments with dirty minds, please, LOL.

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