Final answer:
Physical security measures for protecting an installation from a terrorist threat include using metal detectors, implementing civil defense measures including anti-terrorism legislation, enhancing critical national infrastructure, and utilizing intelligence and counterintelligence services.
Step-by-step explanation:
Given a terrorist threat, physical security measures that can be used to protect an installation from terrorist attack include:
- Using metal detectors as a preventive measure to search for explosives and weapons. This approach, as shown by military practice, helps to identify and eliminate threats before they can cause harm.
- Implementing civil defense and emergency preparedness measures, which also includes anti-terrorism legislation like the Patriot Act, ensuring government agencies can act effectively against potential threats.
- Enhancing the resilience of critical national infrastructure, by strengthening physical and cyber defenses to prevent disruption of essential services.
- Utilizing intelligence services to detect and defeat external terrorist threats and utilizing counterintelligence services to protect against internal threats, ensuring national security on multiple fronts.
Focusing on preventive measures and emergency response can significantly reduce the risk of terrorist attacks and mitigate their potential impact.