Benutzer:Jo Weber/Sieberg-Ambraseys-Skala
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Die Sieberg-Ambraseys-Skala beschreibt auf einer sechsteiligen Skala die Stärke der Auswirkungen von Tsunamis und wurde Anfang der 1960er Jahre von Nicholas Ambraseys auf der Grundlage der 1927 vom deutschen Geophysiker August Heinrich Sieberg entwickelten Sieberg-Skala vorgeschlagen. Sie beruht ähnlich wie die Mercalli-Skala auf makroseismischen Beobachtungen.
Sieberg-Ambraseys-Skala
Die Sieberg-Ambraseys-Skala ist wie folgt aufgebaut:
| I | Very light. Wave so weak as to be perceptible only on tide-gauge records. |
| II | Light. Wave noticed by those living along the shore and familiar with the sea. On very flat shores generally noticed. |
| III | Rather strong. Generally noticed. Flooding of gently sloping coasts. Light sailing vessels carried away on shore. Slight damage to light structures situated near the coasts. In estuaries reversal of the river flow some distance upstream. |
| IV | Strong. Flooding of the shore to some depth. Light scouring on man-made ground. Embankments and dikes damaged. Light structures near the coasts damaged. Solid structures on the coast injured. Bid sailing vessels and small ships drifted inland or carried out to sea. Coasts littered with floating debris. |
| V | Very strong. General flooding of the shore to some depth. Quay-walls and solid structures near the sea damaged. Light structures destroyed. Severe scouring of cultivated land and littering of the coast with floating items and sea animals. With the exception of big ships all other type of vessels carried inland or out to sea. Big bores in estuary rivers. Harbor works damaged. People drowned. Wave accompanied by strong roar. |
| VI | Disastrous. Partial or complete destruction of manmade structures for some distance from the shore. Flooding of coasts to great depths. Big ships severely damaged. Trees uprooted or broken. Many casualties. |
Überarbeitete Tsunami-Skala von 2001
Die zwölfteilige Skala wurde 2001 von Gerassimos Papadopoulos und Fumihiko Imamura entwickelt. Sie beruht ebenfalls auf makroseismischen Beobachtungen, ist jedoch im Gegensatz zur Sieberg-Skala an den überwiegend zehn- oder zwölfteiligen Intensitätsskalen für Erdbeben orientiert. Die Skala wurde 2001 auf dem International Tsunami Symposium in Seattle präsentiert, wurde jedoch im Abschlussbericht des Symposiums nicht erwähnt.[1]
Die Skala ist an verschiedenen Effekten ausgerichtet: den Auswirkungen auf Menschen, auf Objekte wie Boote und auf Gebäudeschäden. Versuchsweise wurde von den Autoren der Skala die Höhe der Tsunamiwelle mit der Stärke korreliert.
| Stärke | Kurzbeschreibung | Höhe in m | Auswirkungen auf Menschen | Auswirkungen auf Objekte | Gebäudeschäden |
|---|---|---|---|---|---|
| I | Not felt. | ||||
| II | Scarcely felt. | Felt by few people onboard small vessels. Not observed on the coast. | No effect. | No damage | |
| III | Weak. | Felt by most people onboard small vessels. Observed by a few people on the coast. | No effect. | No damage | |
| IV | Largely observed | Felt by all onboard small vessels and by few people onboard large vessels. Observed by most people on the coast. | Few small vessels move slightly onshore | No damage | |
| V | Strong | 1 | Felt by all onboard large vessels and observed by all on the coast. Few people are frightened and run to higher ground | Many small vessels move strongly onshore, few of them crash into each other or overturn. Traces of sand layer are left behind on ground with favorable circumstances. Limited flooding of cultivated land | Limited flooding of outdoor facilities (such as gardens) of near-shore structures |
| VI | Slightly damaging | 2 | Many people are frightened and run to higher ground | Most small vessels move violently onshore, crash strongly into each other, or overturn | Damage and flooding in a few wooden structures. Most masonry buildings withstand |
| VII | Damaging | 4 | Many people are frightened and try to run to higher ground | Many small vessels damaged. Few large vessels oscillate violently. Objects of variable size and stability overturn and drift. Sand layer and accumulations of pebbles are left behind. Few aquaculture rafts washed away. | Many wooden structures damaged, few are demolished or washed away. Damage of grade 1 and flooding in a few masonry buildings |
| VIII | Heavily damaging. | 4 | All people escape to higher ground, a few are washed away | Most of the small vessels are damaged, many are washed away. Few large vessels are moved ashore or crash into each other. Big objects are drifted away. Erosion and littering of the beach. Extensive flooding. Slight damage in tsunami-control forests and stop drifts. Many aquaculture rafts washed away, few partially damaged | Most wooden structures are washed away or demolished. Damage of grade 2 in a few masonry buildings. Most reinforced-concrete buildings sustain damage, in a few damage of grade 1 and flooding is observed |
| IX | Destructive | 8 | Many people are washed away | Most small vessels are destroyed or washed away. Many large vessels are moved violently ashore, few are destroyed. Extensive erosion and littering of the beach. Local ground subsidence. Partial destruction in tsunami-control forests and stop drifts. Most aquaculture rafts washed away, many partially damaged | Damage of grade 3 in many masonry buildings, few reinforced-concrete buildings suffer from damage grade 2 |
| X | Very destructive. | 8 | General panic. Most people are washed away | Most large vessels are moved violently ashore, many are destroyed or collide with buildings. Small boulders from the sea bottom are moved inland. Cars overturned and drifted. Oil spills, fires start. Extensive ground subsidence | Damage of grade 4 in many masonry buildings, few reinforced-concrete buildings suffer from damage grade 3. Artificial embankments collapse, port breakwaters damaged |
| XI | Devastating | 16 | Lifelines interrupted. Extensive fires. Water backwash drifts cars and other objects into the sea. Big boulders from sea bottom are moved inland. | Damage of grade 5 in many masonry buildings. Few reinforced-concrete buildings suffer from damage grade 4, many suffer from damage grade 3 | |
| XII | Completely devastating | 32 | Practically all masonry buildings demolished. Most reinforced-concrete buildings suffer from at least damage grade 3 |
Einzelnachweise
- ↑ L. Graziani, A. Maramai und S. Tinti: A revision of the 1783–1784 Calabrian (southern Italy) tsunamis. Natural Hazards and Earth System Sciences, Bd. 6, S. 1053–1060, 2006 (pdf; 470 Kb, englisch)
Literatur
- Nicholas N. Ambraseys: Data for investigation of seismic sea waves in the Eastern Mediterranean. Bulletin of the Seismological Society of America, Bd. 52, S. 895–913, 1962
- Tsunami Glossary. IOC Technical Series, 85, UNESCO Intergovernmental Oceanographic Commission, Paris 2008 (pdf; 5,38 Mb, englisch)
Weblinks
- Andrew Alden: Sieberg-Ambraseys Tsunami Intensity Scale.
- Andrew Alden: Tsunami Intensity Scale of 2001.
- Lee Walklins: Infrequently Asked Questions. TsuInfo Alert, Washington Department of Natural Resources, Division of Geology and Earth Resources. Bd. 2, Nr. 5, Oktober 2000 (pdf; 370 Kb, englisch)
