Survivalist come in many different varieties, and sometimes the language used to describe them can be somewhat confusing.
Here's a basic definition from Wikipedia:
“Survivalism is a movement of individuals or groups (called survivalists or preppers) who actively prepare for emergencies, including possible disruptions in social or political order, on scales from local to international. Survivalism also encompasses preparation for personal emergencies, such as job loss or being stranded in the wild or under adverse weather conditions. The emphasis is on self-reliance, stockpiling supplies, and gaining survival knowledge and skills. Survivalists often acquire emergency medical and self-defense training, stockpile food and water, prepare to become self-sufficient, and build structures such as survival retreats or underground shelters that may help them survive a catastrophe.”
I'm old enough to remember civil defense drills in the schools and some people building fallout shelters in their backyards which were eventually turned into swimming pools.