SQl Server: Corrupt Logs Files: Why?
Paul Randal is probably the undisputed expert in Sql Server corruption.  

According to him, 99.8% of all cases of corruption that he has seen were caused by the IO subsystem.  You might find some interesting information here (Myths around causing corruption).

He also talks about doing root-cause analysis here (My SQL Server Database is Corrupt - Now What?!)

The first thing I'd be doing is asking my storage guys for another disk drive and moving all of my logs there.  This 'might' solve the problem if your current log disk drive is having problems, but it wouldn't be a guarantee since there are other possibilities that might be causing your problem.