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Compound-Hazard Stacking

The planning failure in which co-occurring hazards interact through shared drivers, infrastructure, or response resources, so their joint impact exceeds — and the available capacity falls below — what a plan built from independent single-hazard analyses predicts.

Core Idea

Compound-hazard stacking is the planning failure in which multiple hazards co-occur and interact — sharing drivers, infrastructure, or response resources — so their joint impact exceeds what independent single-hazard plans predict, and the capacity available against the joint event falls below the sum of the standalone capacities. Hazard catalogues are built one hazard at a time; couplings violate the independence assumption; and the realised compound event exposes the interaction terms. Fukushima, the 2020 hurricane-plus-pandemic season, and California's heat-grid-wildfire cycle are documented cases.

Scope of Application

Compound-hazard stacking lives across the emergency-management, disaster-risk-reduction, and critical-infrastructure-planning subfields concerned with co-occurring hazards.

  • Hurricane plus pandemic — the 2020 season, distancing constraining shelters while COVID consumed surge capacity.
  • Heat plus grid stress plus wildfire — California's coupled shutoffs removing air-conditioning during heat.
  • Earthquake plus tsunami plus nuclear release — Fukushima's marginally designed seawall and backup power.
  • Flood plus power outage — Sandy's flooded pumping stations and basement generators.
  • Pandemic plus economic crisis plus civil unrest — three events sharing personnel and governance bandwidth.

Clarity

Naming the pattern exposes the load-bearing assumption a hazard-by-hazard catalogue makes — that hazards occur independently — and pins down how it fails through three named couplings: shared drivers, shared infrastructure, shared response resources. The frame shifts from a list of "or" scenarios to a matrix of "while-also" ones. It also keeps apart two non-additivities: impacts exceeding the marginal sum, and — never seen by standalone analysis — capacity falling below it, distinct from a sequential cascade.

Manages Complexity

Allowing hazards to co-occur produces a combinatorial blow-up of pairs and triples. The concept tames it not by enumeration but by naming the only three pathways through which any two hazards interact, collapsing a combinatorial scenario space into a small checklist applied edge by edge. The three pathways partition the surprise into three trackable terms — impact super-additivity, capacity sub-additivity, probability undercount — so only the coupled cells of a co-occurrence matrix need deep work.

Abstract Reasoning

The construct licenses edge-screening on a hazard graph — asking of each pair only the three coupling questions. It predicts the specific failure term from the coupling type. It supports diagnostic recovery of the missing capacity term standalone analysis cannot see. It keys interventions to the coupling found — harden, de-conflict, or recompute. And it draws boundaries against sequential cascades and single rare events, directing the frame to the blind spot between independently sound plans.

Knowledge Transfer

Within emergency management and infrastructure planning the construct transfers as mechanism — the three-coupling screen and three interaction terms apply to any co-occurring hazards, carrying across the documented compound events without translation. Beyond disaster-risk fields the underlying pattern — non-additive interaction of simultaneous stressors — is synergy_and_antagonism applied to the hazard substrate, recurring as co-instances in toxicology, medicine, finance, and reliability. That parent carries the lesson (with cascade, black_swan, and risk_pooling as neighbors); the three named pathways stay home.

Relationships to Other Abstractions

Local relationship map for Compound-Hazard StackingParents appear above the current abstraction, mutual partners to the right, and children below. Node labels state whether each abstraction is prime or domain-specific; colors identify relation types.Compound-HazardStackingDOMAINPrime abstraction: Synergy and Antagonism — is part ofSynergy andAntagonismPRIMEPrime abstraction: Correlated Capacity Demand — is a kind ofCorrelatedCapacity DemandPRIME

Current abstraction Compound-Hazard Stacking Domain-specific

Parents (2) — more general patterns this builds on

  • Compound-Hazard Stacking is a kind of Correlated Capacity Demand Prime

    Compound-Hazard Stacking is the emergency-planning species of Correlated Capacity Demand, where co-occurring hazards jointly load shared response capacity sized under independence.

  • Compound-Hazard Stacking is part of Synergy and Antagonism Prime

    A positive interaction effect—joint harm above the specified independent-hazard baseline—is an internal constituent of Compound-Hazard Stacking.

Hierarchy paths (2) — routes to 2 parentless roots

Neighborhood in Abstraction Space

Compound-Hazard Stacking sits in a sparse region of the domain-specific corpus (73rd percentile for distinctiveness): few abstractions share its structure, so a faithful description tends to retrieve it precisely.

Family — Unclustered & Miscellaneous (309 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-07-12