You can delete an entire log from Log Policies. You might want to delete a log if it is from a system that is no longer monitored. Deleting a log deletes all the log sources and corresponding log files, but does not prevent future automatic reinstatement of the log and its log sources when a new message is received for the log. To stop new messages, disable logging for all of the log sources instead of deleting the log.

For the steps to delete a log, see Deleting Items.