The ORA-1092 error is indicating that the instance abnormally terminated while connected to the Oracle database. This can occur when creating the database. Unfortunately, there are quite a few reasons why this error has occurred, so you'll nee d to do some further investigation as to the real cause. The first place to look is your Alert Log. The Alert Log is created in the directory specified by the BACKGROUND_DUMP_DEST parameter. If you did not set this parameter, the location defaults to the $ORACLE_HOME/admin/db_name/bdump directory, where db_name is your $ORACLE_SID.
You can open up the alert log with a text editor such as 'vi.' Then look for your CREATE DATABASE statement. Shortly after this command, you will find error messages indicating why the CREATE DATABASE statement failed. It may be something as simple as an improper kernel configuration to support Shared Memory. Or it could be many other reasons. Once you know why the instance terminated, the fix is often quickly found.