Tsunamis
My Blogs (olelog) are mainly based on my daily
reading of earth science news.
Here on whatonearth.olehnielsen.dk I try to weave
some of the pieces together to a greater whole with added background info.
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Tsunamis |
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My Blogs (olelog) are mainly based on my daily
reading of earth science news.
Here on whatonearth.olehnielsen.dk I try to weave
some of the pieces together to a greater whole with added background info.
|
||
Tsunami
is a Japanese word for a sea wave of local or distant origin that results from
large-scale seafloor displacements associated with large earthquakes, major
submarine slides, or exploding volcanic islands. Actually it derives from 'tsu'
meaning 'harbour, and 'nami' meaning 'wave' (see the japanese sign to the left)
- it is said to have been coined by fishermen who returned to their port to
find the area around the harbour devastated, even though they had not experienced
any unusual waves in the open sea. It is NOT a tidal wave. Tidal waves are caused
by the forces of the moon, sun, and planets upon the tides, as well as the wind
as it moves over the water.
Posted on Thursday, 8. December 2005, 11:28:18
It
could happen again, and sooner than expected. Two tectonic plates, the Australian
and the Eurasian plate (or more precisely the Burma subplate), meet just off
Sumatra's south-west coast. It was in this boundary zone that the earthquake
occurred that triggered the boxing day tsunami now nearly a year ago. That earthquake
was, as I am sure you will remember, near the Aceh province, the most northerly
part of Sumatra. Prof Sieh, speaking at the American Geophysical Union Fall
Meeting (5–9 December 2005, San Francisco, California, USA), says the
concern of scientists is now focused on events further south still, to a region
known as the Mentawai islands patch.
BBC News of 7 December 2005 at:
http://news.bbc.co.uk/1/hi/sci/tech/4505818.stm
Abstract
Posted on Thursday, 13 October 2005, 10:50:02
Analysis of sound waves produced in the Indian Ocean by the Boxing Day Tsunami,
2004, have shown that monitoring stations set up to detect atomic explosions
could help predict the path of a tsunami. Such stations were set up to implement
the A-bomb test ban treaty, but they could be involved in the new Indian Ocean
tsunami warning system, if the commission of the treaty organisation (CTBTO)
gives its permission. The results were reported in the journal Geophysical
Research Letters. See BBC News at:
http://news.bbc.co.uk/1/hi/sci/tech/4330286.stm
Tsunami is a Japanese word for a sea wave of local or distant
origin that results from large-scale seafloor displacements associated with
large earthquakes, major submarine slides, or exploding volcanic islands. It
is NOT a tidal wave. Tidal waves are caused by the forces of the moon, sun,
and planets upon the tides, as well as the wind as it moves over the water.
Here you will find some good tsunami links for more information about tsunamis: http://www.realinsurance.com.au/Article-Library/Ultimate-List-of-Tsunami-Resources.aspx. 2004 produced 7 tsunamis, so they are not really seldom. The historically most
renowned is probably the Krakatau Tsunami (Indonesia) in 1883. The largest wave
reached heights of 40 meters above sea level and killed over 34,000 people.
That tsunami was caused by a volcanic eruption (the Krakatau Volcano collapsed).
Ole
Posted on Tuesday, 15. November 2005, 11:06:40
Earthquake and Tsunami - Japan
A strong earthquake (magnitude around 7) shook northern Japan early Tuesday
15 November, triggering a small tsunami that struck coastal towns about 200
miles from the epicentre.
This event is in the Pacific plate in the bending zone before subduction, a normal-faulting event related to flexure of the lithosphere rather than the more dangerous thrust faulting typical of subduction zones. (See my log of Monday, 7. November 2005)
foxnews.com:
http://www.foxnews.com/story/0,2933,175556,00.html
geology.about.com:
http://geology.about.com/b/a/219149.htm
USGS
Earthquake Hazards Program: http://earthquake.usgs.gov/eqinthenews/2005/usfkbr/
Ole
Posted on Monday, 14. November 2005, 20:29:44
Krakatau tsunami
One of the greatest natural disasters in modern history was the eruption of the Krakatau (or Kakatoa) volcano in 1883. The following tsunami killed 36,000 people. If a similar explosion of the same power happened today, the tsunami might kill about one million people.
Anak Krakatau, Krakatau's child, was born about 70 years ago and now grows six meters a year. If its growth rate doesn't decrease, the world will face another great tragedy, says Indonesian volcanologist Supriyatman Sutavijaya from the Indonesian University of Volcanology and Geology. If the processes in the magma chamber maintains the current speed, another explosion will happen in 140 years.
Pravda at http://english.pravda.ru/science/19/94/377/16448_Krakatau.html
SFGate.com: http://www.sfgate.com/cgi-bin/article.cgi?f=/news/archive/2005/01/24/financial1017EST0041.DTL
Ole
Posted on Friday, 7. October 2005, 10:00:09
Tsunami warning systems
Yesterday brought some good news.
Indonesia will position two sensor buoys off the coast of Sumatra island this month and launch a mobile phone text service as part of a tsunami early warning system to be completed in 2008 according to
Yahoo News of Thursday 6 October at http://uk.news.yahoo.com/06102005/323/tsunami-warning-system-taking-shape-indonesia.html
On Thursday 6 October India approved a $28 Million plan to set up an early warning system for ocean disasters like tsunamis according to
Planet Ark at: http://www.planetark.com/dailynewsstory.cfm/newsid/32872/story.htm
Ole
Posted on Thursday, 29. September 2005, 11:21:05
Tsunamis
The Boxing Day tsunami 2004 was the largest tsunami in history, hitting the coastlines of all countries around the Indian Ocean.
A similar tsunami could hit New Zealand’s biggest city Auckland according to an article in The New Zealand Herald of 27 September 2005.
Tsunamis cannot be prevented, but there are means to save lives and reduce material damage.
First of all an early warning system like the one that exists for the Pacific Ocean is of paramount importance, so that people can get to higher grounds and/or away from the coastline/beach in time.
It is however also possible to reduce the possibilities of material damage.
The countries around the Indian Ocean will have to work together on possible solutions.
ASEAN (Association of Southern Asian Nations) has just held its First Joint Disaster Drill After Indian Ocean Tsunami.
On a more local scale ISDR (Institute for Sustainable Development and Research - India) held a National Workshop on Tsunami Rehabilitation, 23-25 September 2005.
Pictures on http://isdronline.com/tsunamiprogramme/firstworkshop.asp show how a compound wall around a house can protect the house against tsunami waves.
Ole
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