What device is typically triggered to indicate that unauthorized access has occurred in a secure location?

The device that is typically triggered to indicate unauthorized access in a secure location is an alarm. Alarms are specifically designed to alert individuals or security personnel when a breach of security occurs. They can be activated in various scenarios, such as when a door or window is opened without authorization or when an intrusion is detected through other means.

While sirens, cameras, and motion detectors play important roles in security systems, they serve different functions. For instance, sirens often accompany alarms as a means of alerting nearby individuals, but they do not independently indicate unauthorized access. Cameras serve the purpose of monitoring and recording activities, providing visual evidence rather than directly signaling an alarm. Motion detectors can trigger alerts but are usually components of an overall alarm system rather than standalone indicators of unauthorized access.

Thus, the proper function of an alarm is to provide immediate notification of unauthorized access, making it the most suitable answer in this context.