OEM nmi.log file growing

We have shutdown one of our databases for extended maintenance. The nmi.log is growing about 1k per minute with the following messages. Short of removing the database from the listener, which I do not really want to do since the database will eventually be brought back up, how can I stop the messages.  
Jeffrey BeckstromDatabase AdministratorGreater Cleveland Regional Transit Authority1240 W. 6th StreetCleveland, Ohio 44113(216) 781-4204 Received on Wed Jul 18 2001 - 12:58:37 CDT