Recasting “low probability, high consequence events”

A magnitude 9.0 earthquake in the Cascadia subduction zone off of the Pacific Northwest coastline has been called a “low probability, high consequence event,” notwithstanding caveats that the earthquake is “scientifically impossible to predict”.

My aim here is to bring to the reader’s attention a very different way to think about Cascadia M9 earthquake (M9, for short).

The argument

Real-time experienced infrastructure operators and managers do worry–and for obvious reasons–about the effects of an M9 on their infrastructures, in this case, the interconnected backbone systems for water, electricity, telecoms and roads. These professionals, however, do not see their “what-if scenarios” for M9 framed typically in terms of probabilities and consequences.

For them, thinking through M9 has two foci: nonmeasurable uncertainties accompanied with disproportionate effects. No presumption is made that “accompanied with” is causal or correlative. The point is that both nonmeasurability and disproportionality both convey important information for their infrastructure operations before, during and after the disaster. Indeed, this information is especially significant when causal understanding is most obscure(d).

I also claim that had we an analytic framework that took nonmeasurable uncertainties and disproportionate effects as its starting point, the policy and management options would differ not only from those of experts wedded to the low-probability-high-consequence typology.

Unique properties of M9 and the experience base of infrastructure operators and emergency managers

For those infrastructure operators and emergency managers we interviewed, the Cascadia M9 earthquake will be an unfolding catastrophe of unimaginable proportions, and not just for their infrastructures. Wider society and economy are at stake. What makes M9 unimaginable is that there is no closure rule for “what-if” scenarios. For those knowledgeable about infrastructures, there’s always a new scenario that merits attention, and more so for the unimaginably bad.

Further, the impacts of M9 will be unpredictably localized with respect to the infrastructure systems as well as interconnected and amplified in unforeseen ways. “Unpredictably localized” entails having new nonmeasurable uncertainties compared to what the professionals already know about their infrastructures from past disruptions and worse. “Interconnected and amplified” mean having unforeseen effects that are demonstrably disproportionate when compared to what they already know about their infrastructures during disruptions and worse.

Nonmeasurability of uncertainties and disproportionality of effects are what their experience tells the professionals to associate with a Cascadia M9 earthquake. These are infrastructure professionals come to the M9 earthquake already knowledgeable about uncertainties and impacts, especially those that can or cannot be measured with effects inside or outside previous bandwidths and known proportions.

Informally, this means. . .

“Operating blind” with the loss of telemetry, cellphones and power is how one infrastructure operator described the experience in an ice storm. But it’s that “operating,” even then and now or ahead under worse circumstances, that the infrastructure’s real-time professionals can help us better understand. It’s their alertness we need to know more about. “I don’t know that we answer until we’re in the event in a lot of cases,” echoed a city infrastructure manager for water with respect to M9. So too “coming to those answers” is something we should want to know more about before misleadingly lapsing into conventional jargon about probabilities and risks.

“Coping with risk” is a highly misleading characterization of this behavior when an important part of that “coping” is proactive improvisations and where the unit and level of improvisation is not risk, as bundles of adjustable probabilities and consequences, but a provisional match between then-and-there tasks and then-and-there resources called “emergency response.”

Proposed alternative framework

It is important that an alternative analytic framework be based in (1) how experienced infrastructure and emergency management real-time staff see Cascadia M9, (2) import no slippery slope to conventionalized risk analysis, and (3) demonstrate the centrality of information-rich nonmeasurable uncertainties and disproportionate effects.

(My research colleague, Paul Schulman, has played the key role in developing the four element below and is in no way responsible for the Implications drawn.)

We identified four elements that our previous work on large interconnected infrastructures indicated were critical to emergency management: (1) the different types of interconnectivity (sequential, mediated, reciprocal, more) between and among infrastructures involved in immediate response and initial recovery for the backbone infrastructures of electricity, water, telecoms and roads; (2) the points (thresholds, phases, transitions) at which the types of interconnectivity shift during infrastructure failure, response and initial recovery; (3) the importance in immediate response of jointly undertaken improvisations around real-time system control variables–think electricity frequency and voltage for electricity, water pressure for potable water supplies and firefighting, water flows for ports and vessel traffic–relied upon by more than one of the backbone infrastructures—all of which are in turn managed to (4) a performance standard of requisite variety (that is, effectiveness in immediate response and initial recovery are measured against how well real-time task demands and real-time resources are matched then-and-there, if only temporarily).

If this weren’t already a long blog entry, I would now describe and justify each element. But at this point what is more important is that the reader recognize how difficult these four elements, individually and together, make it to revert to anything like the language of probabilities and consequences, Bayesian or otherwise. It is also important to recognize how nonmeasurability and disproportionality are consistent with and foregrounded by having multiple, shifting interconnectivities, improvisations and the never-before-seen by experienced operators and emergency managers.

Three framework implications will have suffice as illustrative.


First, removing oneself from Cascadia M9 interconnectivities, shifts, and need for just-on-time improvisations must be an option. This ranges from moving out of coastal Oregon and Washington State beforehand to having better evacuation strategies during and afterwards. It’s not clear to me if the states’ emergency preparedness plans and education programs present “getting-out-of-Dodge” as an option.

Second and for those staying in the coastal and western parts of the states, there is clear priority in developing and testing continuity of operations plans (public sector), business continuity plans (private sector) and what are variously called devolution plans and orders of succession (i.e., who will do what when the positions for “being in charge” are suddenly vacated). It is not clear to me how current modeling and tabletops exercises around M9 incorporate prototyping and ground-truthing very different scenarios for public and private continuity and succession arrangements.

Third, the framework calls for majorly rethinking the role of “improvisations.” To characterize something like topping off a fuel tank for a back-up as a one-off incidental or side work is to miss entirely the point, namely: Improvisations, especially those involving more than one infrastructure during immediate response, cannot be isolated from the interconnectivities and shifts they occur within and give arise to, especially because (not: “even if”) they revolve around momentary matches in requisite variety.

Last point, for now

Some readers will object: “Whoa! Moving to and living in another area involves new risks and with it weighing. . .And what about the poor or vulnerable who can’t move? . .”

But you are not balancing risks or probabilities or consequences when choosing to move out because of a Cascadia M9 earthquake, at least from the experienced-based perspective of the framework. From the experience base described here, the drivers are not risks, but the interconnectivities and important shifts in nonmeasurable uncertainties and disproportionate effects.

That those we interviewed appear not to be moving out of western Oregon and Washington State tells us, I think, a great deal about the professional reluctance to move into (another set of) unstudied or unstudiable but nevertheless interconnected conditions.

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