A Disturbance Primer for Urban Systems
[Box 1 An Example of Disturbance: Sixty-four acres of Baltimore’s central business district was destroyed by a fire in 1904. The origin of the fire is unknown. It was extinguished when winds changed and backed the fire against the Jones Falls stream. Fire fighting equipment brought in from other cities could not be used due to the incompatibility of the hose fittings with Baltimore hydrants. Referred to as the Great Fire, this event was one of the last unintentional fires in a major American city. Note that the 1906 post-earthquake fire in San Francisco owed much of its origin to intentional generation of firebreaks. (Olson 1997)]
Press and Pulse. These terms contrast events that have sharp attack and short duration — Pulses — with events that establish persistent new conditions. While the term “pulse” may be essentially the same as disturbance, press can have either the direct physical effects like disturbances or the more physiological effects of stresses. Note that the term pulse does not necessarily imply a regular rhythm of events.
The Urban Context
“engineering” resilience as capacity to return to a fixed equilibrium point.