There are several types of industrial infrastructures in the US that as citizens, we depend on daily to live. Such infrastructures are Agricultural, Telecommunication, Transportation, Energy, Financial, Political, & Defense. Shall any one of these infrastructures be damaged or severely threatened, Americans will find themselves thrown into a frontier like mode of survival.
Some of our national infrastructures are centralized geographically in certain regions.
Agriculture: beef, wheats & grains - Midwest, vegetables & greens, Monterey County, CA, fruits - California, Florida. Dairy products are generally produced in close proximity to where they will be delivered.
Financial: NYC, The San Francisco/Bay Area is number two based on the fact that the headquarters of several financial firms are located in SF and that many Fortune 500 companies are situated nearby in Silicon Valley.
Energy: Louisiana,Mississippi Delta, Texas, New Jersey, Northern California. Though much of America's energy infrastructure is based on the delivery of foreign oil, many oil refineries required to make gasoline are located in the US.
Currently we are witnessing some our infrastructures under threat by natural made disasters or harsh weather systems. The flooding in the Midwest is damaging crops, undermining the local housing infrastructure, and effecting the transportation of goods sent from local farms and distributers to national markets via shipping on the Mississippi River.
Wild fires or brush fires through out California are threatening much of the produce crops that supply much of the country. In this age of "global warming" awareness we can't spare to lose any more trees - not that I am a "tree hugger" or anything.
Let's look at a scorecard of recent man made and natural disasters that have impacted key infrastructures in the US:
Financial/Political: Terrorist attack 9/11 - NYC/Washington D.C
Energy: Hurricane Katrina - States bordering the Gulf of Mexico
Biggest Threat to key US infrastructures yet to happen is an Earthquake in Northern California which will cause severe flooding in the Delta region located on the Northeast SF Bay Area threatening Chevron and Valero refineries: National Impact: Energy
Structural damage to Fortune 500 headquarter buildings; National Impact: Financial, Telecommunication
Loss of livestock and produce emanating from fires, floods, and landslides: National Impact: Agricultural
Now I am not a doomsday guru but my two cents says it is quite important to follow the US Boy Scout mantra and, "ALWAYS BE PREPARED."