There is no way to stop Oracle from recording log switch in Alert log. Your database is experiencing high DML activity, so you can think about increasing the size of online redologs.
However, you must remember the downfall, checkpoints can occur less frequently, causing higher recovery time if you have not tuned other aspects to take care of recovery time (like checkpoint interval).

Originally quoted by gandolf989:
......You may also want to add additional log groups.....
How will adding additional log groups affect number of log switches??