Friday, 4 December 2009
tsunami images
a couple of images here
the first an image that illustrates what happened during the 2004 tsunami
the second illustrates the difference between a regular wind induced waves and a tsunami in terms of water movements
national geographic tsunami facts
Tsunamis
Click here to find out more!
Tsunami: Killer Waves
The most infamous tsunami of modern times hit Indian Ocean shorelines on the day after Christmas 2004. That tsunami is believed to have packed the energy of 23,000 Hiroshima-type atomic bombs. Some 150,000 people were killed in a single day.
Photograph by Deshakalyan Chowdhury
The most infamous tsunami of modern times hit Indian Ocean shorelines on the day after Christmas 2004. That tsunami is believed to have packed the energy of 23,000 Hiroshima-type atomic bombs. Some 150,000 people were killed in a single day.
A tsunami is a series of ocean waves that sends surges of water, sometimes reaching heights of over 100 feet (30.5 meters), onto land. These walls of water can cause widespread destruction when they crash ashore.
These awe-inspiring waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly it displaces the water above it and launches the rolling waves that will become a tsunami.
Most tsunamis, about 80 percent, happen within the Pacific Ocean’s “Ring of Fire,” a geologically active area where tectonic shifts make volcanoes and earthquakes common.
Tsunamis may also be caused by underwater landslides or volcanic eruptions. They may even be launched, as they frequently were in Earth’s ancient past, by the impact of a large meteorite plunging into an ocean.
Tsunamis race across the sea at up to 500 miles (805 kilometers) an hour—about as fast as a jet airplane. At that pace they can cross the entire expanse of the Pacific Ocean in less than a day. And their long wavelengths mean they lose very little energy along the way.
In deep ocean, tsunami waves may appear only a foot or so high. But as they approach shoreline and enter shallower water they slow down and begin to grow in energy and height. The tops of the waves move faster than their bottoms do, which causes them to rise precipitously.
A tsunami’s trough, the low point beneath the wave’s crest, often reaches shore first. When it does, it produces a vacuum effect that sucks coastal water seaward and exposes harbor and sea floors. This retreating of sea water is an important warning sign of a tsunami, because the wave’s crest and its enormous volume of water typically hit shore five minutes or so later. Recognizing this phenomenon can save lives.
A tsunami is usually composed of a series of waves, called a wave train, so its destructive force may be compounded as successive waves reach shore. People experiencing a tsunami should remember that the danger may not have passed with the first wave and should await official word that it is safe to return to vulnerable locations.
Some tsunamis do not appear on shore as massive breaking waves but instead resemble a quickly surging tide that inundates coastal areas.
The best defense against any tsunami is early warning that allows people to seek higher ground. The Pacific Tsunami Warning System, a coalition of 26 nations headquartered in Hawaii, maintains a web of seismic equipment and water level gauges to identify tsunamis at sea. Similar systems are proposed to protect coastal areas worldwide.
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Click here to find out more!
Tsunami: Killer Waves
The most infamous tsunami of modern times hit Indian Ocean shorelines on the day after Christmas 2004. That tsunami is believed to have packed the energy of 23,000 Hiroshima-type atomic bombs. Some 150,000 people were killed in a single day.
Photograph by Deshakalyan Chowdhury
The most infamous tsunami of modern times hit Indian Ocean shorelines on the day after Christmas 2004. That tsunami is believed to have packed the energy of 23,000 Hiroshima-type atomic bombs. Some 150,000 people were killed in a single day.
A tsunami is a series of ocean waves that sends surges of water, sometimes reaching heights of over 100 feet (30.5 meters), onto land. These walls of water can cause widespread destruction when they crash ashore.
These awe-inspiring waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly it displaces the water above it and launches the rolling waves that will become a tsunami.
Most tsunamis, about 80 percent, happen within the Pacific Ocean’s “Ring of Fire,” a geologically active area where tectonic shifts make volcanoes and earthquakes common.
Tsunamis may also be caused by underwater landslides or volcanic eruptions. They may even be launched, as they frequently were in Earth’s ancient past, by the impact of a large meteorite plunging into an ocean.
Tsunamis race across the sea at up to 500 miles (805 kilometers) an hour—about as fast as a jet airplane. At that pace they can cross the entire expanse of the Pacific Ocean in less than a day. And their long wavelengths mean they lose very little energy along the way.
In deep ocean, tsunami waves may appear only a foot or so high. But as they approach shoreline and enter shallower water they slow down and begin to grow in energy and height. The tops of the waves move faster than their bottoms do, which causes them to rise precipitously.
A tsunami’s trough, the low point beneath the wave’s crest, often reaches shore first. When it does, it produces a vacuum effect that sucks coastal water seaward and exposes harbor and sea floors. This retreating of sea water is an important warning sign of a tsunami, because the wave’s crest and its enormous volume of water typically hit shore five minutes or so later. Recognizing this phenomenon can save lives.
A tsunami is usually composed of a series of waves, called a wave train, so its destructive force may be compounded as successive waves reach shore. People experiencing a tsunami should remember that the danger may not have passed with the first wave and should await official word that it is safe to return to vulnerable locations.
Some tsunamis do not appear on shore as massive breaking waves but instead resemble a quickly surging tide that inundates coastal areas.
The best defense against any tsunami is early warning that allows people to seek higher ground. The Pacific Tsunami Warning System, a coalition of 26 nations headquartered in Hawaii, maintains a web of seismic equipment and water level gauges to identify tsunamis at sea. Similar systems are proposed to protect coastal areas worldwide.
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tsunami timeline
this is a piece i have found on the net.
a timeline of tsunamis which indicates when and gives an idea of where tsunamis happen in the world.
a timeline of tsunamis which indicates when and gives an idea of where tsunamis happen in the world.
551 Beirut destroyed by earthquake and tsunami.
1607 Tidal wave swept along the Bristol Channel, killing 2000 people. (Possibly tsunami)
1700 The Cascadia Earthquake, one of the largest earthquakes on record, ruptures the Cascadia subduction zone offshore from Vancouver Island to northern California, creating a tsunami logged in Japan and oral traditions of the American First Nations.
1755 1755 Lisbon earthquake: In Portugal, Lisbon is destroyed by a massive earthquake and tsunami, killing 60,000 - 90,000 people.
1792 Old lava dome collapses in Kyushu, Japan when Mount Unzen volcano erupts - resulting avalanche and tsunami kills about 14300
1906 Typhoon with tsunami kills an estimated 10,000 persons in Hong Kong.
1929 1929 Grand Banks earthquake: Off the south coast of Newfoundland in the Atlantic Ocean, a Richter magnitude 7.2 submarine earthquake centered on Grand Banks, breaks 12 submarine transatlantic telegraph cables and triggers a tsunami that destroys many south coast communities in the Burin Peninsula area, killing 28. As of 1997, it is Canada's most lethal earthquake.
1946 14-meter high tsunami strikes Hilo, Hawaii - 173 dead, thousands injured.
1960 May 22
1971 A tsunami 85 m high rises over the Ryukyu Islands in Japan. It throws a 750-ton block of coral 2.5 km inland.
1971 A cyclone and tsunami in the Bay of Bengal, in Orissa State in India, kills 10,000.
1979 A tsunami in Nice, France kills 23 people.
1993 A magnitude 7.8 earthquake off Hokkaido, Japan launches a devastating tsunami, killing 202 on the small island of Okushiri, Hokkaido.
1998 A tsunami triggered by an undersea earthquake destroys 10 villages in Papua New Guinea, killing an estimated 1,500, leaving 2,000 more unaccounted for and thousands more homeless.
2004 One of the worst natural disasters in recorded history hits southeastern Asia when the strongest earthquake in 40 years hits the entire Indian Ocean region. The massive 9.3 magnitude earthquake, epicentered just off the west coast of the Indonesian island of Sumatra, generates enormous tsunami waves that crash into the coastal areas of a number of nations including Thailand, India, Sri Lanka, the Maldives, Malaysia, Myanmar, Bangladesh, Burma and Indonesia. The official death toll in the affected countries stands at 186,983 while more than 40,000 people are still missing.
2004 tsunami simulations
looking into tsunamis led me to this video.
a computer generated simulation of the 2004 tsunami.
seeing it in this perspective makes it seem almost calming and gentle.
to me its like looking at a still pond that has had a stone dropped into it and the waves look like ripples.
a computer generated simulation of the 2004 tsunami.
seeing it in this perspective makes it seem almost calming and gentle.
to me its like looking at a still pond that has had a stone dropped into it and the waves look like ripples.
http://www.guardian.co.uk/news/blog/2009/nov/23/flooding-weather
A weather blog on the Guardian website which had a live update on the flooding situation
A weather blog on the Guardian website which had a live update on the flooding situation
Guardian news report 2
Bad weather prompts flood warnings and caravan park rescue
Eleven people rescued in North Yorkshire as Met Office forecasts snow in northern England over coming week
Floods have wreaked havoc across northern England in recent weeks. Photograph: Andrew Yates/AFP/Getty Images
Residents had to be rescued from a flooded caravan park in North Yorkshire overnight, as the Environment Agency issued 31 flood warnings across the UK.
Eleven people were rescued from caravans in North Yorkshire as heavy rain threatened towns and villages in the county, while the Met Office issued a weather warning for south-east England and east Anglia.
The Met Office said temperatures across Britain are expected to drop to as low as -6C over the next two days, and snow is predicted in northern England and Scotland over the coming week, potentially hindering recovery efforts in flood-devastated areas of Cumbria.
North Yorkshire fire and rescue service said they were summoned to Knaresborough, four miles north east of Harrogate, at 2am this morning.
"Eleven people in total were assisted from caravans by ourselves at a caravan park near the river Nidd in Knaresborough overnight," a spokeswoman said.
"We sent out 14 firefighters in three fire appliances [engines] and a boat."
She said the boat was used to transport the people to the safety of a "local clubhouse" in Knaresborough. The spokeswoman said fire crews would be returning to the river today to check water levels.
The environment agency has 31 flood warnings – its second most serious measure – in place across the UK, including 20 in North Yorkshire. A spokesman for the agency said it came "very close to issuing a severe flood warning overnight, but the threat dropped".
The Met Office issued a weather warning for south-east England and East England overnight as rain spread from North Yorkshire. Devon was also hit by heavy rainfall as water levels rose by as much as 4ft on Sunday.
Robin Downton, a forecaster at the Met Office, said the days ahead would see low temperatures before a wet weather front arrives from the Atlantic.
"We are expecting widespread frost on Monday night and in frost prone areas such as the west Midlands and north-east of England temperatures will drop as low as -5 or -6C," he said.
Some parts of Britain experienced the first snows of winter on Saturday. The Llanberis Pass in north Wales saw an inch and a half of snowfall as well as some higher ground in Scotland such as the Cairngorms.
Cockermouth in Cumbria, which was submerged just over a week ago by more than 12 inches of rainfall in 24 hours, was another area which could be hit by as much as 3-5cm of snow, MeteoGroup UK said.
The Prince of Wales visited the area over the weekend to boost morale as locals cleaned up the destruction caused by the floods. The prince thanked emergency services for their work in the recovery operation, and paid tribute to PC Bill Barker who died while turning traffic away from a bridge when it collapsed.
He also urged visitors not to cancel holidays in Cumbria, where businesses are struggling to recover after the damage.
Army engineers have begun building the foundations of a footbridge to reconnect the two halves of Workington where one bridge collapsed. Households in the Northside area of Workington face long detours to get to the town centre or local schools.
Six bridges in the county have collapsed since last week's heavy rainfall, and Downton said more rain was due this week and would "continue to be a nuisance to areas which have been hit by flooding". But Cumbria would be spared from the worst as the heavy fall moves eastwards, he added.
The flooding during the weekend caused two deaths. Paula Deacon, 57, died after slipping and falling off a bridge into the river Seaton at Hessenford, in east Cornwall, and police pulled the body of a man thought to be in his 30s from the river Taff in Cardiff.
Despite the bad weather, the Met Office predicted last week that Britain would have a mild winter because of the El Niño developing in the Pacific Ocean
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