Which type of alarm suggests that an intrusion is happening but remains silent in order to avoid detection?

The type of alarm that indicates an intrusion while remaining silent to avoid detection is known as a silent burglar alarm. These alarms are specifically designed to alert law enforcement or security personnel without drawing attention to the situation. This stealth feature allows for a response to be initiated without the knowledge of the intruder, increasing the chances of apprehending them and minimizing the risk to individuals on the premises.

Silent burglar alarms are often used in scenarios where discretion is crucial—such as in a bank or jewelry store—where an audible alarm might prompt immediate flight from the intruder, allowing them to escape before help can arrive. This type of alarm is effective in both residential and commercial settings where security needs to be heightened without alerting potential threats.

The other types of alarms, such as audible alarms, are designed to make noise to alert anyone in the vicinity. Manual alarms require human intervention to trigger, while covert alarms serve the purpose of being discreet but may not necessarily indicate a silent alert specifically for intrusions.