6.8.5 — Multi-Hazard Warning Systems — maturity: live
Multi-Hazard Risk Atlases
Continuously updated, satellite-derived national risk atlases that map overlapping flood, seismic, drought, landslide and storm-surge hazards at sub-10 km resolution for planning and policy.
Satellite-fed risk atlases give planners a single, continuously updated map of overlapping hazards — flood, fire, seismic and storm — before the next disaster strikes.
National planners, infrastructure ministries and insurers need a single, authoritative picture of where hazards intersect — yet most countries rely on static, decadal maps stitched together from foreign datasets they cannot interrogate or update. When a cyclone track overlaps a subsiding delta that also sits above a fault zone, the compound risk is invisible unless all three data layers are current, consistently projected and held in sovereign hands. Satellite-derived inputs — SAR-based ground deformation, multispectral flood extent, thermal drought indices, optical landslide scarring — turn a paper atlas into a living model.
A dedicated constellation of optical and SAR microsatellites, combined with GNSS-reflectometry and thermal-infrared payloads, feeds a continuous ingest pipeline that refreshes every hazard layer on a sub-weekly cadence. Change detection algorithms flag new deformation signals, expanding drought polygons or post-event landslide zones within hours of acquisition, pushing delta updates into the national atlas rather than waiting for a five-year revision cycle. The atlas geometry is fixed to a sovereign geodetic reference frame so layers from different missions align without depending on a commercial vendor's proprietary datum.
The operational payoff is threefold: planners can zone new infrastructure away from compound-risk corridors before ground is broken; emergency managers can query the atlas the moment a trigger event occurs to identify secondary hazard zones that will activate next; and reinsurers and development banks can price sovereign risk against data the government itself controls rather than data licensed from a foreign platform. Countries that own this capability stop negotiating with vendors every time they need an updated exposure layer for a World Bank project or a UN Sendai Framework progress report.
Frequently asked
What exactly is a 'multi-hazard risk atlas' and how does satellite data feed into it?
A multi-hazard risk atlas is a spatially explicit database that overlays hazard footprints (flood extent, wildfire burn probability, seismic shaking intensity, storm-surge inundation) with exposure layers (population, infrastructure, agriculture) and vulnerability indices. Satellites supply the hazard and land-cover layers through radar, optical, and thermal sensors, typically refreshed on daily-to-weekly cycles. The atlas outputs risk scores at the sub-district level that planners use for zoning, insurance pricing, and evacuation routing. Without satellite inputs, these layers must be derived from sparse ground observations that are both slow and geographically patchy.
Why can't a country just subscribe to a commercial risk-data service instead of building its own?
Commercial services like Verisk, RMS, or AIR Worldwide provide excellent actuarial models but are licensed products whose underlying data, algorithms, and update schedules are proprietary. A sovereign government cannot audit them, modify hazard definitions to match national standards, or guarantee continuity of access during a geopolitical crisis. Owning the satellite assets and ingestion pipelines means the atlas remains operable even when commercial relationships break down — which is precisely when disaster risk information is most critical.
What orbit and sensor mix is recommended for a national multi-hazard constellation?
A LEO constellation at 500–600 km altitude is the practical default, combining C-band SAR for cloud-penetrating flood and landslide mapping with medium-resolution multispectral sensors for vegetation stress, burn scars, and urban damage assessment. A notional national system could start with 6–12 microsatellites (50–150 kg each) to achieve daily revisit, supplementing with data-sharing agreements under the Committee on Earth Observation Satellites (CEOS) Disaster Risk Reduction Working Group. GNSS-RO payloads added to the same bus provide atmospheric moisture profiling that feeds the hydrometeorological hazard layers.
How does the Sendai Framework shape what nations are expected to deliver?
The Sendai Framework for Disaster Risk Reduction 2015–2030, monitored by UNDRR, requires signatory states to report progress against seven global targets, including Target E (substantially increase national and local disaster risk reduction strategies) and Target G (enhancing international cooperation). These targets implicitly require countries to maintain up-to-date, multi-hazard risk assessments — which are difficult to produce without satellite Earth observation. UNDRR's Sendai Framework Monitor accepts satellite-derived data as evidence, making a sovereign atlas both a policy deliverable and a reporting asset.
How often does the atlas need to be refreshed to remain operationally useful?
Background hazard layers (seismic zonation, long-run flood return periods) need updating every 1–5 years as new ground-truth data or updated probabilistic models become available. Dynamic layers — active fire perimeters, flood inundation extent, cyclone track forecasts — need refreshing every 1–24 hours during an event. A well-designed system separates the static probabilistic backbone from the real-time event layers, allowing different refresh cadences without reprocessing the entire atlas. Planet's daily-revisit constellation and ESA's Copernicus Emergency Management Service are useful benchmarks for what 'operationally useful' latency looks like.
Can small or lower-income nations realistically afford to own this capability?
Not unilaterally in most cases — but regionally, yes. A shared microsatellite constellation operated by a regional bloc (modelled on SERVIR, which serves South/Southeast Asia and East Africa jointly through NASA and USAID) dramatically reduces per-country cost. Ground-segment sharing further reduces operational overhead. The World Bank's PROBLUE and GFDRR programmes have co-financed national disaster risk information systems in over 90 countries; adding sovereign sensing capability to those investments is an incremental, not a revolutionary, step in cost.
What are the key data interoperability standards a national atlas must conform to?
At minimum: ISO 19115-1 for metadata, OGC WMS/WFS for geospatial data services, and the UNDRR's Risk Data Open Standard (RDOS) for hazard, exposure and vulnerability tables. GeoTIFF or Cloud-Optimised GeoTIFF (COG) is the de facto raster exchange format, while GeoJSON and GeoPackage handle vector layers. Aligning to these standards from the outset ensures the national atlas can plug into regional platforms like the Pacific Catastrophe Risk Assessment and Financing Initiative (PCRAFI) or the Caribbean Risk Information System (CRIS) without costly reformatting.
How do you handle the uncertainty and communicate it honestly to decision-makers?
Best practice, codified in ISO 19157 (Data Quality) and the IPCC's guidance on uncertainty language, requires each atlas layer to carry explicit confidence intervals, source provenance, and vintage dates. Visualisation tools should render probabilistic outputs as ranges — for example, '1-in-100-year flood extent with 90% confidence band' — rather than single deterministic lines that imply false precision. UNDRR's DesInventar methodology and the JRC's Global Earthquake Model (GEM) foundation both publish uncertainty-aware risk outputs that national atlases can adopt as templates.
