(4b) Tsunamis Introduction to Geophysics and Planetary Physics Geophysics 75

Tsunamis The Japanese word Tsunami means „harbor wave“ (above, wood carving by Hokusai – note Fuji San in the back). Far right: Simulation of the Tsunami, caused by the 1960 Chile earthquake, which lead to sever devastation in Hawaii (right) and in Japan (Source: USGS). Geophysics 76

Tsunamis A Tsunami caused by a submarine earthquake (schematic). In contract to normal ocean waves the whole water column is in motion. Right: Tuna fish, left in Maumere on the Island of Flores (Indonesia) after the 1992 tsunami (Source: P&S, 1994). Geophysics 77

Lisbon, 1755 The Great Lisbon Earthquake was one of the most important natural disasters. On November 1, 1755 the west coasts of Portugal, Spain and Morocco were hit by a tsunami. The five to ten meter wave killed people in Lisbon alone. It was – until December 2004 – the most severe Tsunami in (human) history. Pictures: Geophysics 78

Krakatoa, 1883 In 1883 Krakatoa erupted after 200 years of silence (left, G. Symmons). The tremendous explosion could be heard as far as 4000 km. It caused a Tsunami, which was responsible for most of the casualties. The paddle steamer “Berouw” was moved several kilometers inland. Anak Krakatau „The child of Krakatoa“ (above, NASA) rises continuously. Geophysics 79

Lituya Bay, 1958 Lituya Bay is a fjord located in southern Alaska ( Geophysics 80

Lituya Bay, 1958 On July 9, 1958 the Lituya Bay was overrun by the largest impulse wave ever recorded, caused by an earthquake (M=7.9), that trig- gered an enormous landslide. 30 Million m 3 of rock fell into the sea and imitated a 520 m wave. On the other side of the bay the forest was completely erased up to a height of about 400 m. Source: UoSC Geophysics 81

A Latent Risk Debris fans on the ocean floor around the Hawaiian islands are the remnants of giant landslides in the past (left). These events caused tsunamis with wave heights way above 100 m. This also explains the (up to then) enigmatic discovery of large coral blocks on the island of Lanai – 325 m above sea level. Source: “Spektrum der Wissenschaft, 6/2004”. Geophysics 82

Only the satellite “Quickbird” saw the reflux of the first tsunami wave near the city of Kalutara on the west coast of Sri Lanka at 10:20 local time (far left). In the following wave trough the water retreated up to 300 Meter from the shore (left). All pictures: „Spektrum der Wissenschaft 2/2005“. cm Geophysics 83 Indian Ocean,

Satellite measurements of the wave height on the open ocean (Source: NOAA). Geophysics 84 Indian Ocean,

Aceh, Sumatra (Source: DLR) Geophysics 85 Indian Ocean,

Geophysics 86 Indian Ocean, Aceh, Sumatra (Source: DLR)

Indian Ocean, Source: National Institute of Advanced Industrial Science and Technology, Japan Geophysics 87

Japan, Even more devastating than the strong earthquake itself was the tsunami that reached the east coast of Honshu only a few minutes later – with waves up to 20 m (Source: Kyodo) Geophysics 88

Japan, Containers (above, picture: Itsuo Inouye) and ships (top left: NHK, bottom left: Kyodo) were thrown around like toys. Geophysics 89

Japan, Source: Kyodo Geophysics 90

Japan, The wave moved inland as far as 5 km. Satellite pictures before (left) and after the tsunami (right) show the dimension of devastation, as near the city of Natori (Source: GeoEye) Geophysics 91

Japan, The coast near Kashima (Pictures: Digital Globe) Geophysics 92

Japan, Entire cities, like Riku Zentakata became completely erased (Source: Kyodo) Geophysics 93

Tsunamis und Gravity Waves The Tsunami waves initiated atmospheric gravity waves, which affected (due to density-fluctuations in the thermosphere caused) even the orbit of the satellite GOCE (Source: ESA) Geophysics 94

Tsunami, Gravity Waves, and TIDs The gravity waves, intitiated by the Tsunami, could even be observed in the ionosphere, where they caused Travelling Ionospheric Disturbances (TIDs) (Credit: NASA) Geophysics 95

Protective Barriers Also in southern Japan they assessment of possible tsunami wave heights changed dramatically (Credit: Nature). Geophysics 96

Purple circles: Earthquakes with M > 7.5. The earthquake in Crete in the year 365 AD caused a tsunami, which killed up to People in. The Messina earthquake 1908 had a death toll of The thereby released tsunami killed more than 1000 (Spektrum der Wissenschaft). Geophysics 97 Tsunamis in Europe

About 8000 years ago, a giant landslide occurred on Mt. Etna: 25 km 3 of rocks and debris dumped into the Ionian Sea, thereby causing a tsunami, which could be traced as far as Israel. The simulation also (nicely) shows the effect of interference (Source: Pareschi et al., GRL, 2006). Geophysics 98