{ "id": "http://connectivity-hub.com/terms/cb39af3e-727f-4768-a285-6ed10b896e57", "type": "Concept", "prefLabel": { "en": "Tsunami (Volcanic Trigger)" }, "definition": { "en": "Tsunami is the Japanese term meaning wave (‘nami’) in a harbour (‘tsu’). It is a series of travelling waves of extremely long length and period, usually generated by disturbances associated with earthquakes occurring below or near the ocean floor (IOC, 2019).

IOC, 2019. Tsunami Glossary, 2019. Intergovernmental Oceanographic Commission (IOC), Technical Series, 85. Fourth Edition. IOC/2008/TS/85 rev.4.

" }, "editorialNote": { "en": [ "source:UNDRR HIPS" ] }, "scopeNote": { "en": [ "A tsunami may also be referred to as a ‘seismic sea wave’ and, incorrectly, a ‘tidal wave’. Volcanic eruptions, submarine landslides, and coastal rock falls can also generate tsunamis, as can a large meteorite impacting the ocean. These waves may reach enormous dimensions and travel across entire ocean basins with little loss of energy. They proceed as ordinary gravity waves with a typical period of between 10 and 60 minutes. Tsunamis steepen and increase in height on approaching shallow water, inundating low-lying areas, and where local submarine topography causes the waves to steepen, they may break and cause great damage (IOC, 2019). Tsunami-like phenomena generated by meteorological or atmospheric disturbances are known as meteotsunami (UNESCO and IOC, 2019). The Intergovernmental Oceanographic Commission (IOC) uses the following terms to assess the scale and impact of a tsunami (IOC, 2019): Travel time: Time required for the first tsunami wave to propagate from its source to a given point on a coastline. Arrival time: Time of the first maximum of the tsunami waves. Inundation or Inundation-distance: The horizontal distance inland that a tsunami penetrates, generally measured perpendicularly to the shoreline. Inundation (maximum): Maximum horizontal penetration of the tsunami from the shoreline. A maximum inundation is measured for each different coast or harbour affected by the tsunami. Inundation area: Area flooded with water by the tsunami. Inundation height: Elevation reached by seawater measured relative to a stated datum such as mean sea level or the sea level at the time of tsunami arrival, at a specified inundation distance. Inundation height is the sum of the flow depth and the local topographic height. Sometimes referred to as tsunami height. Inundation line: Inland limit of wetting measured horizontally from the mean sea level line. The line between living and dead vegetation is sometimes used as a reference. In tsunami science, the landward limit of tsunami run-up. Leading wave: First arriving wave of a tsunami. In some cases, the leading wave produces an initial depression or drop in sea level, and in other cases, an elevation or rise in sea level. When a drop in sea level occurs, sea level recession is observed. Mean height: Average height of a tsunami measured from the trough to the crest after removing the tidal variation. Run-up Tsunami amplitude: Usually measured on a sea level record, it is (1) the absolute value of the difference between a particular peak or trough of the tsunami and the undisturbed sea level at the time, (2) half the difference between an adjacent peak and trough, corrected for the change of tide between that peak and trough. It is intended to represent the true amplitude of the tsunami wave at some point in the ocean. However, it is often an amplitude modified in some way by the tide gauge response. Tsunami period: Amount of time that a tsunami wave takes to complete a cycle, or one wavelength. Tsunami periods typically range from 5 to 60 minutes. Tsunami period is often measured as the difference between the arrival time of the highest peak and the next one measured on a water level record. Tsunami wavelength: The horizontal distance between similar points on two successive waves measured perpendicular to the crest. The wavelength and the tsunami period give information on the tsunami source. For tsunamis generated by earthquakes, the typical wavelength ranges from 20 to 300 km. For tsunamis generated by landslides, the wavelength is much shorter, ranging from hundreds of metres to tens of kilometres. For more terms see IOC (2019).", "Tsunami is the Japanese term meaning wave (‘nami’) in a harbour (‘tsu’). Tsunamis are a series of gravity waves of extremely long (up to hundreds of kilometres) length with periods of 10 to 60 minutes that can travel across ocean basins with little loss of energy. They are usually generated by earthquakes occurring below or near the ocean floor. Approximately 80% of tsunamis are caused by earthquakes, but also by volcanic eruptions, submarine landslides, and coastal rock falls. Tsunami waves, on entering shallow water steepen and increase in height attaining elevations (or runups) of tens to hundreds of meters, inundating low-lying areas and, where local submarine topography causes the waves to steepen, they may break and cause great damage. Tsunamis have no connection with tides; the popular name, tidal wave, is entirely misleading (IOC, 2019). Volcanic tsunamis are defined as those with source mechanisms from erupting and quiescent volcanoes, and include explosions, pyroclastic flows and lahars entering the water, earthquakes preceding or during a volcanic eruption, flank failure (from rock falls to massive debris avalanches), collapse of coastal lava benches, caldera collapse and shock waves from large explosions. Of these mechanisms, only pyroclastic flows, flank failures and caldera subsidence generate damaging tsunamis, as their volumes are larger than one km3. Wavelengths of volcanic tsunamis are shorter than those from earthquakes and undergo more rapid dispersion during propagation. These tsunamis are more hazardous on coastlines close to the volcano. Because of the different potential mechanisms and their possible interactions, numerical simulations of volcano tsunamis, and model-based assessments of hazards from volcano tsunamis, are challenging, compared to those from earthquakes (Day, 2015). The Intergovernmental Oceanographic Commission (IOC) uses the following terms to assess the scale and impact of a tsunami (IOC, 2019): For more terms see IOC (2019)." ] }, "broader": { "id": "http://connectivity-hub.com/terms/51a19ac2-70fa-43d2-bf50-23fe2b363d0a", "prefLabel": { "en": "Volcanogenic" } }, "inScheme": [ { "id": "http://connectivity-hub.com/terms/", "title": { "en": "Climate Connectivity Taxonomy" } } ], "inSchemeAll": [ { "id": "http://connectivity-hub.com/terms/" } ], "@context": { "@version": 1.1, "id": "@id", "type": "@type", "@vocab": "http://www.w3.org/2004/02/skos/core#", "xsd": "http://www.w3.org/2001/XMLSchema#", "dct": "http://purl.org/dc/terms/", "dc": "http://purl.org/dc/elements/1.1/", "schema": "https://schema.org/", "vann": "http://purl.org/vocab/vann/", "ldp": "http://www.w3.org/ns/ldp#", "owl": "http://www.w3.org/2002/07/owl#", "title": { "@id": "dct:title", "@container": "@language" }, "dc:title": { "@id": "dc:title", "@container": "@language" }, "dc:description": { "@id": "dc:description", "@container": "@language" }, "description": { "@id": "dct:description", "@container": "@language" }, "license": { "@id": "dct:license", "@container": "@language" }, "issued": { "@id": "dct:issued", "@type": "xsd:date" }, "created": { "@id": "dct:created", "@type": "xsd:date" }, "modified": { "@id": "dct:modified", "@type": "xsd:date" }, "creator": "dct:creator", "publisher": "dct:publisher", "preferredNamespacePrefix": "vann:preferredNamespacePrefix", "preferredNamespaceUri": "vann:preferredNamespaceUri", "isBasedOn": "schema:isBasedOn", "source": "dct:source", "prefLabel": { "@container": "@language" }, "altLabel": { "@container": [ "@language", "@set" ] }, "hiddenLabel": { "@container": [ "@language", "@set" ] }, "definition": { "@container": "@language" }, "note": { "@container": [ "@language", "@set" ] }, "changeNote": { "@container": [ "@language", "@set" ] }, "editorialNote": { "@container": [ "@language", "@set" ] }, "historyNote": { "@container": [ "@language", "@set" ] }, "scopeNote": { "@container": [ "@language", "@set" ] }, "notation": { "@container": "@set" }, "example": { "@container": "@language" }, "narrower": { "@container": "@set" }, "related": { "@container": "@set" }, "relatedMatch": { "@container": "@set" }, "narrowerTransitive": { "@container": "@set" }, "broaderTransitive": { "@container": "@set" }, "broadMatch": { "@container": "@set" }, "narrowMatch": { "@container": "@set" }, "closeMatch": { "@container": "@set" }, "exactMatch": { "@container": "@set" }, "hasTopConcept": { "@container": "@set" }, "inScheme": { "@container": "@set" }, "topConceptOf": { "@container": "@set" }, "deprecated": { "@id": "owl:deprecated", "@type": "xsd:boolean" }, "isReplacedBy": { "@id": "dct:isReplacedBy", "@container": "@set" } } }