TSU · Physics
Tsunami
PTHA18 offshore probabilistic hazard reuse, propagated to 90 m with coastal amplification and overland attenuation; regional source branches (NEAMTHM18, GAR15) plus non-seismic sources · v1.0 · 2026-08
Sendai / Sanriku — the Tohoku 2011 validation coast
Coastal tsunami screening: offshore probabilistic hazard reused from PTHA18 and propagated to 90 m. A screening climatology for portfolio triage — explicitly not evacuation planning, life-safety zoning, or engineering design.
What ships
Surfaces — P(inundation ≥ 0.5 m) at 50 / 250 / 500-year horizons (500-year is the default planning basis), plus 500-year inundation depth in metres, a five-class zoning cut, uncertainty and coverage. Scored on land within ~15 km of the coast.
Every release: 0–1 score · 5-class band · per-pixel uncertainty · input-coverage mask · STAC item · methodology doc.
Inputs
PTHA18 + GAR15 (Geoscience Australia), NEAMTHM18 (INGV), NGI, GEBCO 2024 bathymetry, SRTM15+, Slab2, NOAA NCEI historical run-up database
Version history
What changed between releases — the same notes that ship with the data. Newest first.
v1.1
2026-09
Correction release. Fixes an inland-attenuation defect on below-datum coastal plains and replaces the fixed 15 km scored band with a physical domain. Offshore hazard, sources and the Tōhoku calibration are unchanged.
- Inland decay measured from the shoreline. v1.0 measured the overland energy-line distance from any pixel below sea level, so subsided plains, polders and deltas (about 1.2 % of scored land, affecting attenuation over roughly 8 %) restarted the decay from zero. On the Ishinomaki plain that placed a 500-yr inundation depth of 8 m some 13 km inland, where the 2011 event never reached. Distance is now taken from the GSHHG shoreline, with the per-tile seam removed at the same time.
- Below-datum land is scored. Land is defined by the shoreline mask, not the sign of the elevation, so Dutch polders, New Orleans and post-2011 subsided Japanese plains return values rather than nodata.
- Physical scored domain. Ocean-connected land below 50 m within 30 km of the coast replaces the fixed 15 km band; the inland edge now follows terrain rather than a line. Inland water bodies are excluded.
- Bare-earth elevation. GEDTM30 v1.2 (global) with DeltaDTM v1.1 on coasts, over Copernicus. Building and canopy height no longer read as ground; a 2–7 m residual remains in dense city cores and is documented.
- New audit gates at the sites where v1.0 failed, so this class of defect cannot ship again.
- Known limitation: tsunami propagation up river channels (the Kitakami reached 49 km in 2011) is not modelled.
v1.0
2026-08
Initial vintage. Coastal band only; see README for the scored domain.
- Three-basin offshore hazard. Published, commercially-clean reference models used where each is authoritative: PTHA18 (Indo-Pacific), NEAMTHM18 (NE Atlantic + Mediterranean), GAR15 Global Tsunami Model (Caribbean, US East Coast, S Atlantic). The Atlantic is genuinely modelled, not reported as zero.
- Non-seismic sources. Volcanic sector collapse, submarine eruption and shallow-seamount explosion contribute their own rates through a displacement kernel calibrated on ten published back-analyses — so the Sunda Strait carries Anak-Krakatau-type hazard that a seismic-only model reports as nothing.
- Coastal amplification at 90 m. Green's-law shoaling to a common reference depth plus a nearshore-slope-dependent run-up factor, over a seamless GEBCO + Copernicus bathy-topo surface.
- Inundation with an observed-calibrated inland decay. Reproduces the 2011 Tōhoku Sendai-plain inundation limit (3 km wet, 5 km marginal, 8 km dry) and its peak run-up (39.9 m modelled vs 39.26 m observed).
- Three horizons (50 / 250 / 500 yr) plus the 500-year inundation depth.
- Honest nulls. Deep inland and open ocean are nodata by design; land beyond wave reach scores zero. Where the model reads lower than the historical record (Cádiz 1755), the validation report says so rather than tuning the number.
Other hazards
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