Tsunami¶
A generated water-surface gravity-wave event that propagates from a source disturbance and may produce highly local or distant coastal effects.
Core Idea¶
A tsunami is a source-generated event in which a water-surface gravity disturbance travels through a water body. Seabed displacement and landslides can launch one; NOAA also recognizes a pressure-forced meteotsunami as a qualified weather-driven subtype. Source, propagation and shore impact are distinct: an earthquake does not always launch a tsunami, and coastal flooding is not required before a traveling tsunami has that name.[^ref-8bc965592e25]
Scope of Application¶
The necessary roles are a generating disturbance, a water body with its geometry, and a launched propagating wave. Shore interaction may be observed but is not a universal condition. Under a linear long-wave approximation, travel speed is about c ≈ √(gh) for gravitational acceleration g and depth h; this does not give an exact speed for breaking, impact or overland flow. The 2004 Sumatra survey and Miller's 1958 Lituya Bay investigation document unlike earthquake/ocean and rockslide/confined-bay settings, without implying one universal wave height or travel range.[ref-c88b1964fed1][ref-9ae3cd420c7d][^ref-92e8e49e5380]
Clarity¶
Ask in order: what disturbed the water, what wave propagated, and what was measured where? A coastal wave-height or run-up observation is local evidence, not automatically the wave's offshore amplitude. A model of deep-water travel and a field survey answer different questions. Ordinary sustained wind waves, storm surge, astronomical tides and a standing seiche without a launched traveling wave do not satisfy the same source-and-propagation pattern; a meteotsunami can.[ref-8bc965592e25][ref-c88b1964fed1][^ref-9ae3cd420c7d]
Manages Complexity¶
Separating generator, path and shore response prevents an event label from becoming a height formula. The Sumatra team's initial findings contain locally varying coastal evidence. Miller used eyewitness and physical traces to reconstruct a wave within one Alaskan bay. Each source supports its own setting, not a prediction that the other setting would reproduce its measured height.[ref-9ae3cd420c7d][ref-92e8e49e5380]
Abstract Reasoning¶
A candidate passes the identity test if a disturbance launched a wave that propagated through water. Remove the launched wave and the earthquake, slide or pressure disturbance alone is not a tsunami. Remove an observed shore impact and an offshore traveling tsunami may still exist; only one consequence disappears. The water-body and source roles remain constitutive even as earthquake, landslide and pressure-forcing variants differ.[ref-8bc965592e25][ref-92e8e49e5380]
Knowledge Transfer¶
The shared structure transfers from the Indian Ocean to Lituya Bay: generation in water, propagation, and site-dependent interaction. Their sources and geometries differ, so a case's measured height cannot be transferred by analogy. The live Wave Prime names the internal propagating constituent through the approved composition/part_of relation, with Wave parent_in_child. A tsunami is a larger water-specific event, not a strict subtype inheriting every idealized linear or no-net-transport condition of Wave. No independent cross-domain instance of the named Tsunami identity is shown.[ref-9ae3cd420c7d][ref-92e8e49e5380]
Example¶
2004 Indian Ocean event at Sumatra. An undersea earthquake generated a tsunami. An international field team reported about 20–30 m wave-height evidence at the northwest end of Sumatra, with other observations varying by site. Mapped roles: source → earthquake-related seabed displacement; water body → Indian Ocean and Sumatra coast; traveling wave → tsunami reaching that coast; shore evidence → local measured heights and inundation; regime-bound propagation relation → the linear long-wave c ≈ √(gh) approximation may frame offshore travel only where its assumptions apply, with no case-specific speed inferred. The report is an initial coastal survey, not a uniform basin-wide amplitude or a direct estimate of source slip.[ref-8bc965592e25][ref-9ae3cd420c7d]
1958 Lituya Bay event. An earthquake-triggered rockslide entered Gilbert Inlet, generating a giant wave that moved through confined Lituya Bay. Miller combined eyewitness accounts with tree-damage and shoreline evidence of extreme local run-up. Mapped roles: source → rockslide; water body → confined bay; traveling wave → bayward propagation; shore evidence → site-specific run-up and damage; regime-bound propagation relation → the deep-ocean linear speed expression is not imposed on this near-impact wave. Its run-up is not a universal landslide-tsunami height.[ref-92e8e49e5380][ref-c88b1964fed1]
Relationships to Other Abstractions¶
Current abstraction Tsunami Domain-specific
Parents (1) — more general patterns this builds on
-
Tsunami is part of Wave Prime
Propagating water-surface wave motion is an identity-bearing constituent within a tsunami event.
Hierarchy path (1) — routes to 1 parentless root
- Tsunami → Wave
Neighborhood in Abstraction Space¶
Tsunami sits in a sparse region of the domain-specific corpus (90th percentile for distinctiveness): few abstractions share its structure, so a faithful description tends to retrieve it precisely.
Family — Unclustered & Miscellaneous (2551 abstractions)
Nearest neighbors
- Wave shoaling — 0.83
- Wind Fetch — 0.81
- Longshore drift — 0.80
- Rossby whistle — 0.80
- Mesoscale Eddy — 0.79
Computed from structural-signature embeddings · 2026-10-08
Not to Be Confused With¶
A source earthquake without a generated water wave, a local splash with no launched propagation, storm surge, astronomical tides, or standing oscillation alone. A pressure-forced meteotsunami remains a positive subtype when it supplies the traveling-wave roles. The name's portable wave component is already represented by live Wave; the named Tsunami remains a water-specific event with a constitutive source, not a Prime abstraction for all generated hazards.[^ref-8bc965592e25]
References¶
[^ref-8bc965592e25]: National Oceanic and Atmospheric Administration, The science behind tsunamis, official explainer, “What is a tsunami?,” “How landslides generate tsunamis,” and “What is a meteotsunami?” sections. The page explicitly distinguishes meteotsunami from storm surge and seiche. [^ref-c88b1964fed1]: National Weather Service JetStream, Tsunami Propagation, official NOAA/NWS module, “Fast Facts” and depth/speed discussion. The text gives the gravity–depth square-root speed; this entry states the linear long-wave regime as the approximation's scope. [^ref-9ae3cd420c7d]: Sumatra International Tsunami Survey Team, The 26 December 2004 Indian Ocean Tsunami, Initial Findings from Sumatra, U.S. Geological Survey field report, based on 20–29 January 2005 survey, Introduction and linked Methods/photographs. The source title uses a colon after “Tsunami”; the linked comma is a transcription for full work identity. [^ref-92e8e49e5380]: Don J. Miller, Giant Waves in Lituya Bay, Alaska, U.S. Geological Survey Professional Paper 354-C (1960), printed pp. 63–70 and 72–76; original full report. The report supports rockslide generation and local wave evidence, not a universal run-up magnitude.