Disasters That Multiply, Models That Don't

Natural hazards increasingly occur as compound or cascading events — an earthquake triggers a submarine landslide that triggers a tsunami; climate change intensifies wildfire that destabilizes slopes, leading to post-fire debris flows; a volcanic eruption produces atmospheric waves, a tsunami, and ionospheric disturbances simultaneously. Current hazard assessment and emergency management treat each hazard independently, missing the amplification and interaction effects that often cause the worst damage. We lack system-of-systems understanding of how land-ocean-atmosphere-ice interactions drive extreme events, and how longer-term trends (climate change, increased solar activity) change the frequency and intensity of short-term extremes.

The 2022 Hunga Tonga eruption produced atmospheric pressure waves, a Pacific-wide tsunami, and ionospheric disturbances — all from a single volcanic event — but no existing hazard framework would have predicted this cascade. Post-fire debris flows in California have killed dozens and caused billions in damage in areas where residents were told the fire risk had passed. Compound flooding (storm surge + river flooding + intense rainfall) is increasing in frequency along the US Gulf and Atlantic coasts. Insurance models, building codes, and emergency management systems that treat hazards independently systematically underestimate risk from compound events, leading to underinvestment in resilience.

Hazard research is siloed by discipline: seismologists study earthquakes, volcanologists study eruptions, hydrologists study floods, atmospheric scientists study storms — but cascading events cross all these boundaries simultaneously. Observations span two or more GEO divisions (AGS, EAR, OCE, OPP), and cross-divisional proposals have historically been difficult to fund because reviewers are specialists in one hazard type. Process models for individual hazards cannot capture cascading interactions because they lack coupling mechanisms between domains (e.g., how volcanic ash loading affects atmospheric wave propagation, how wildfire alters hillslope hydrology). Multi-scale processes (local to planetary, instantaneous to long-term trend) require fundamentally new modeling frameworks that do not yet exist. Space weather hazards (geomagnetic storms affecting power grids) are rarely considered alongside terrestrial hazards despite affecting the same critical infrastructure.

Interdisciplinary research proposals that span two or more geoscience domains — the EC2H DCL explicitly encourages this and has no deadline. System-of-systems modeling frameworks that couple atmospheric, solid earth, ocean, and cryospheric processes. Integration of hazard chain observations from recent events (Hunga Tonga 2022 is a natural experiment in multi-domain coupling). Development of compound hazard metrics that go beyond single-hazard return periods. Workshops and research coordination networks that break down disciplinary boundaries between hazard communities.

A student team could analyze a historical cascading hazard event (e.g., 2018 Kilauea eruption → lava flow → ocean entry → laze plume → coastal hazard, or 2021 Marshall Fire → debris flow risk) by mapping the hazard chain, identifying which interactions were predicted vs. unexpected, and proposing what monitoring or modeling would have enabled earlier warning. Alternatively, a team could build a simplified coupled model linking wildfire intensity to post-fire debris flow probability for a specific California watershed, using publicly available fire perimeter and digital elevation data. Relevant skills: geoscience, hazard modeling, GIS, data science, systems engineering.