windows 8 audit log files location

On a windows 8 PC, what is the actual file which stores local logon events. We have a copy of all files from a Windows 8 PC, and need some utility to review the actual audit log events, but need to know whcih file they are stored in first (and where that file lives by default), plus any suggestions on a tool which can take orphansed event log files and produce a report from them (i.e. allow you to filter for logon events).