The GCP BigQuery Large Scan rule is designed to trigger notifications whenever a query in Google BigQuery processes more than 1 GB of data. This rule utilizes GCP audit logs to identify any instances where the total amount of bytes billed or processed by a query exceeds the specified threshold. With its implementation, security teams can monitor and control potentially excessive resource usage and prevent unintended cost overruns or performance issues. The rule operates in a manner where it categorizes queries based on the size of data scanned, thus helping organizations optimize their usage of GCP BigQuery and ensuring no anomalous activities are carried out by users without proper oversight. The results of this monitoring can feed into larger data governance frameworks, enhancing visibility over query operations and promoting best practices regarding data access and usage.