What type of frequencies can travel through breaking glass and surrounding structures?

The correct answer identifies shock frequencies, which are the types of frequencies that can effectively travel through breaking glass and surrounding structures. When glass shatters, it creates a sudden release of energy, producing shock waves that transmit through materials such as walls and floors. These shock frequencies can propagate over distances, often allowing them to be detected by sensors designed to identify break-in events.

In contrast, high-frequency tones and ultrasound frequencies, while they can be transmitted through air and may be relevant in other contexts, typically do not have the same capacity to penetrate solid materials as well as shock frequencies do. Low-frequency vibrations have their own unique propagation characteristics but may not be as closely associated with the immediate effects of breaking glass, which are more abrupt and lead to the generation of shock waves. Understanding the nature of these various frequency types is essential for designing effective intrusion detection systems.