(4b) tsunamis
DESCRIPTION
Introduction to Geophysics and Planetary Physics. Geophysics 65. (4b) Tsunamis. Geophysics 66. Tsunamis. - PowerPoint PPT PresentationTRANSCRIPT
(4b) Tsunamis
Introduction to Geophysics and Planetary Physics
Geophysics 80
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 81
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 82
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 60 000 people in Lisbon alone. It was – until December 2004 – the most severe Tsunami in (human) history. Pictures: http://nisee.berkeley.edu/elibrary/browse/kozak.
Geophysics 83
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 36 000 casualties. The paddle steamer “Berouw” was moved several kilometers inland. Anak Krakatau „The child of Krakatoa“ (above, NASA) rises continuously.
Geophysics 84
Lituya Bay, 1958
Lituya Bay is a fjord located in southern Alaska (http://www.usc.edu/dept/tsunamis).
Geophysics 85
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 m3 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 86
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 87
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 88
Indian Ocean, 26. 12. 2004
Satellite measurements of the wave height on the open ocean (Source: NOAA).
Geophysics 89
Indian Ocean, 26. 12. 2004
Aceh, Sumatra (Source: DLR)
Geophysics 90
Indian Ocean, 26. 12. 2004
Geophysics 91
Indian Ocean, 26. 12. 2004
Aceh, Sumatra (Source: DLR)
Indian Ocean, 26. 12. 2004
Source: National Institute of Advanced Industrial Science and Technology, Japan
Geophysics 92
Japan, 11. 3. 2011
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 93
Japan, 11. 3. 2011
Containers (above, picture: Itsuo Inouye) and ships (top left: NHK, bottom left: Kyodo) were thrown around like toys.
Geophysics 94
Japan, 11. 3. 2011
Source: Kyodo
Geophysics 95
Japan, 11. 3. 2011
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 96
Japan, 11. 3. 2011
The coast near Kashima (Pictures: Digital Globe)
Geophysics 97
Japan, 11. 3. 2011
Entire cities, like Riku Zentakata became completely erased (Source: Kyodo)
Geophysics 98
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 99
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 100
Protective Barriers
Also in southern Japan they assessment of possible tsunami wave heights changed dramatically (Credit: Nature).
Geophysics 101
Purple circles: Earthquakes with M > 7.5. The earthquake in Crete in the year 365 AD caused a tsunami, which killed up to 50 000 People in Alexandria. The Messina earthquake 1908 had a death toll of 70 000. The thereby released tsunami killed more than 1000 (Spektrum d. Wiss.).
Geophysics 102
Tsunamis in Europe
Tsunamis in Europe
About 8000 years ago, a giant landslide occurred on Mt. Etna: 25 km3 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 103