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Tsunami Sample

This page provides a complete sample response for a tsunami hazard from the Active Hazards API endpoint. Tsunami hazards are sourced from the NOAA tsunami warning centers — the sample below is a National Tsunami Warning Center (NTWC) information statement following a magnitude 5.2 earthquake near Amchitka, Alaska, for which no tsunami danger was assessed. The severity of INFORMATION reflects that assessment; a threatened coastline would carry WATCH or WARNING.

Tsunami-Specific Properties

Incident Data

The incident.properties object for a tsunami hazard combines the triggering earthquake's parameters with the warning center's assessment:

  • magnitude / depthKM / epicenter_lat / epicenter_lon - The triggering earthquake

  • locationDescription - Epicenter description as issued (e.g., "110 miles SE of Amchitka, Alaska")

  • severityHeadline - The assessment in one line (e.g., "There is NO tsunami danger from this earthquake.")

  • severity / sourceSeverity / severityStatus - DisasterAWARE severity, the severity as issued by the source, and whether the message is active

  • hazardDescription - Full narrative of the message

  • messageNumber / wmoHeader - Message sequence number and WMO product header (e.g., "WEAK53")

  • tsunamiObservations - "TRUE" when wave observations have been reported, otherwise "FALSE"

  • modelRunId / modelRunOk - Identifier and status of the inundation model run backing the exposure geometry

  • eventDate / reportDate / createDate - Origin time, message time, and record creation (ISO 8601)

  • rawMessage / rawMessageText - The source bulletin

  • status - Lifecycle state ("NEW", "UPDATE")

Features

The features collection contains three features: an INCIDENT point at the epicenter carrying the earthquake and assessment properties, a SMART_ALERT polygon, and an EXPOSURE_AREA polygon. The features collection carries metadata, incidentType, and sourceId at collection level alongside type and features, and each feature's geometry object embeds a copy of the feature's properties. See Feature collections.

Exposure Areas

Tsunami hazards use a single exposure level (level 0, "Tsunami Exposure Area"), delivered as a MultiPolygon of the coastal segments within the warning center's area of responsibility. For a Pacific event the footprint can be very large and cross the antimeridian, which is why the geometry on this record spans the United States, Japan, Russia, and the U.S. Minor Outlying Islands in totalByCountry even though no tsunami was expected.

Source

source is populated for tsunami hazards and identifies the warning center (NTWC).

Sample Response

Note: Coordinate arrays have been replaced with [...] for brevity. In actual API responses, these properties contain complete GeoJSON coordinate arrays. Long text fields have been truncated. All other values are verbatim from the production API as of 2026-09-11.

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