“How can different infrastructures be interdependent without any direct connection?”
Infrastructures can be interdependent in numerous ways. However, one of the most subtle forms is through cause and effect, in which the consequences of one infrastructure failure will carry over into another one. Take for example the 2018 Northern California Wildfires. When the fallen transmission line caused a fire, the smoke that swept into the Bay Area caused the air pollution levels to skyrocket. This made people rush to the hardware stores to purchase protective masks, emptying stocks within hours. Through Logical Interdependence, the supply of gas masks was contingent on the fire resilience in Northern California.