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Introduction to Geophysics and Planetary Physics
Geophysics 80
(4b) Tsunamis
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Geophysics 81
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).
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Geophysics 82
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 PS,
1994).
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Geophysics 83
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.
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Geophysics 84
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.
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Geophysics 85
Lituya Bay, 1958
Lituya Bay is a fjord located in southern Alaska
(http//www.usc.edu/dept/tsunamis).
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Geophysics 86
Lituya Bay, 1958
Source UoSC
On July 9, 1958 the Lituya Bay was overrun by the
largest impulse wave ever recorded, caused by an
earthquake (M7.9), 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.
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Geophysics 87
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.
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Geophysics 88
Indian Ocean, 26. 12. 2004
cm
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 1020 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.
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Geophysics 89
Indian Ocean, 26. 12. 2004
Satellite measurements of the wave height on the
open ocean (Source NOAA).
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Geophysics 90
Indian Ocean, 26. 12. 2004
Aceh, Sumatra (Source DLR)
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Geophysics 91
Indian Ocean, 26. 12. 2004
Aceh, Sumatra (Source DLR)
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Geophysics 92
Indian Ocean, 26. 12. 2004
Source National Institute of Advanced Industrial
Science and Technology, Japan
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Geophysics 93
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)
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Geophysics 94
Japan, 11. 3. 2011
Containers (above, picture Itsuo Inouye) and
ships (top left NHK, bottom left Kyodo) were
thrown around like toys.
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Geophysics 95
Japan, 11. 3. 2011
Source Kyodo
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Geophysics 96
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)
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Geophysics 97
Japan, 11. 3. 2011
The coast near Kashima (Pictures Digital Globe)
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Geophysics 98
Japan, 11. 3. 2011
Entire cities, like Riku Zentakata became
completely erased (Source Kyodo)
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Geophysics 99
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)
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Geophysics 100
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)
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Geophysics 101
Protective Barriers
Also in southern Japan they assessment of
possible tsunami wave heights changed
dramatically (Credit Nature).
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Geophysics 102
Tsunamis in Europe
Purple circles Earthquakes with M gt 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.).
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Geophysics 103
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).