The Dr. Lucy Jones Resilience Equation

In her work with various communities, Dr. Lucy Jones developed the Resilience Equation to help define the pieces that go together to increase or reduce community risk.

(Hazard x Exposure x Fragility) / (Response x Recovery) = Community Risk


Hazard is what the Earth does to us, including wildfires, warming climate, and dryness of the ground. Hazard is increasing due to climate change impacts.

Exposure is the extent and density of the built environment, or where you are located in regards to where the hazard is going. For example, is your city hall the first thing that is going to burn in a wildfire due to its location near lots of dry brush?

Fragility is vulnerability, when applied to people. Applied to communities, it is structural weaknesses. Given the buildings in your community, what are the building codes, fire protections, materials of the building, landscaping choices, and electric system protections?


Community Risk is the impacts of hazard, exposure, and fragility, mitigated by response and recovery.


Response is the planning to improve immediate response, such as search and rescue.

Recovery is the planning to improve long term recovery. The more preparation, the easier it is to recover.


Graph of impact of recovery on economic activity post disaster

Recovery can represent more loss than in the disaster itself. This is why speeding up recovery is what makes a community resilient and viable. Recovery can be sped up with mitigation, planning and better response. Mitigation prevents damage, reducing the need for response. Planning improves response and recovery. Better immediate response improves the long term recovery.

Given this equation, we cannot change our hazard or exposure. Reducing fragility and response has been the main focus of our disaster resources, such as CalFire. We need to focus on our will to recover in order to reduce our community risk.