May 22, 1960 – Chile – An earthquake measuring 9.5 on the Richter scale struck Santiago and Concepcion, triggering tidal waves and volcanic eruptions. Some 5 000 people were killed and 2 million homeless.

March 28, 1964 – Alaska – An earthquake and ensuing tsunami claimed 125 lives and caused about $ 311 million in damage. The quake, measuring 9.2 was felt over a large area of Alaska and parts of western Yukon Territory and British Columbia, Canada.

March 9, 1957 – Alaska – An earthquake of 9.1 hit the islands Andreanof. On Umnak Island, Mount Vsevidof erupted after being dormant for 200 years, generating a tsunami 15 meters high that continued to Hawaii.

December 26, 2004 - Indonesia – An earthquake measuring 9.0 struck the coast of Aceh province on the northern Indonesian island of Sumatra and triggered a tsunami that killed thousands in Sri Lanka, Thailand, Indonesia and India .

November 4, 1952 – Russia – An earthquake of magnitude 9.0 generated a tsunami that struck the Hawaiian islands. There were no fatalities.

January 31, 1906 – Ecuador – A 8.8 earthquake recorded off the coast of Ecuador and Colombia, generating a strong tsunami that killed up to a thousand people. He felt along the Pacific coast of Central America to San Francisco and as far as western Japan.

February 4, 1965 – Alaska – 8.7 magnitude earthquake degrees, the quake generated a tsunami reported to be about 10.7 meters high on Shemya Island.

August 15, 1950 – Tibet / India – 2000 houses, temples and mosques were destroyed in an earthquake of 8.6 Richter. Hardest hit was the Brahmaputra Basin in northeast India. At least 1,500 people died.

February 3, 1923 – Russia – Kamchatka was struck by an earthquake of magnitude 8.5.

February 1, 1938 – Indonesia – An earthquake with magnitude 8.5 in the Banda Sea generated several tsunami caused extensive damage in Banda and Kai, volcanic islands in eastern Indonesia.

January 12, 2009 – Haiti – at 16:53:09 local time with epicenter at 15 km from Port au Prince, Haiti’s capital. According to the U.S. Geological Survey, the quake would have had a magnitude of 7.0 degrees and would have been generated at a depth of 10 kilometers.

Related posts:

1. Earthquakes explained
2. Tsunami explained
3. Toba, supervolcano in Indonesia

Tsunami is a catastrophic ocean wave, mostly caused by a submarine earthquake less than 50 kilometers under the seafloor with a magnitude greater than 6.5 on Richter scale. Near the source of submarine earthquakes, the seafloor is “permanently” uplifted and down-dropped, pushing the water up and down. The potential energy from pushing water is transformed to kinetic  energy seen as the tsunami wave.

Even if a wave is 15 meters high (not likely in tsunamis) it makes a little difference in a hundred meters deep water but, as it comes into shallow water, the wave rises much higher and strikes the shore with very devastating force. In deep water wavelengths are enormous (100km to 200km) and wave heights are pretty small, less than 1 meter but as the waves approach the continental coasts, shallow water reduces the speed of the waves shortening the wavelengths and amplifying wave amplitudes up to 30 meters in just 10 to 15 minutes what is very fast transition. Tsunamis can be also caused by landslides or volcanic eruptions.

Most of tsunamis don’t result in giant destructive waves but some, such as the 2004 Indian Ocean event, are very devastating, both for structures and inhabitants. Offshore earthquake near Indonesian Island of Sumatra caused deadly tsunami that killed more than 230,000 people in 14 different countries, mostly in Indonesia, Sri Lanka, India and Thailand. Earthquake that caused tsunamis was the third largest earthquakes recorded in human history, with magnitude of between 9.1 and 9.3 on Richter scale.

Most of the earthquakes causing dangerous waves and tsunamis are happening on the edges of tectonic plates in areas like Alaska, California, South America and Indonesia.

Related posts:

1. Earthquakes explained
2. 10 strongest earthquakes in modern history
3. Energy from tidal power

Eruptions of  volcano provided the opportunity to many scientists to see how ash from volcano can effect iron levels in the water and how is growth of the vital organism phytoplankton affected.

Phytoplankton is very important to the large eco-systems because it takes carbon dioxide from the atmosphere (like living plants) into the deep sea when it dies. In certain areas growth of phytoplankton is usually limited by low concentrations of iron in the water and it usually blooms in the spring and dies back in the summer.

Scientists are testing theory that the volcanic eruption increased iron in the water and thus will prolong the spring blooms of phytoplankton into summer.

Leading professor Eric Achterberg says:

“We are extremely lucky that the volcano has given us a fantastic natural experiment. Normally iron is so low here that after a massive spring bloom, it doesn’t grow well in the summer. But after the volcano there’s been a lot more iron falling in to the ocean, so we have a fantastic opportunity to check whether iron makes the bloom last longer. We are seeing enhanced iron levels compared with other years and we think that’s because of the volcano. We need to do a lot more analysis back at the lab before we can confirm the volcano has caused extra phytoplankton growth.”

Despite this research opportunity offered by Icelandic volcano, scientists had to abandon initial aim of their expedition to test normal iron levels in the non affected sea region.

The oceans take up 40% of all carbon dioxide from the atmosphere so this is pretty significant for all life on Earth.

Related posts:

1. Tambora – biggest eruption recorded
2. Volcanoes and global warming
3. Argentinian lake maybe holds secret of life on Earth

Kent Wells from BP told media after oil stopped spewing that he felt very good not to see any oil going into the Gulf of Mexico while he tried to maintain his emotions. It is understandable that key BP men are quite reserved after all those false starts, tries and promises in hope that oil drama is finally over.

President Barack Obama also told media in a brief press conference: “For almost 90 days of this environmental disaster, all of us have taken hope from the image of clean water instead of oil spewing into the Gulf. The new cap is good news.”

The biggest problem for scientists and workers in attempt to stop oil leak was a fact that other leaks could be produced under the sea floor due to high pressure gauges if containment cap is placed over oil well. Submarines are also scouring the sea floor with sonar detectors and so far they didn’t detect any sign of floor breaches.

The US government and BP are now discussing issue to decide whether to keep the oil well shut off or to reopen some of the tubes to reduce the pressure. Drilling has now been suspended to allow work on the necessary containment cap and following days will show results of today’s and yesterday’s efforts.

Related posts:

1. Deepwater Horizon oil spill
2. Scientis propose big experiment to study Gulf oil spill
3. Exxon explores algae biofuels as alternative energy

Frustrated with limited data on the BP oil gusher, a group of independent scientists has proposed a large experiment that would give a clearer understanding of where the oil and gas are going and where they’ll do the most damage.

The scientists say their mission must be undertaken immediately, before BP kills the runaway well. They propose using what’s probably the world’s worst oil accident to learn how crude oil and natural gas move through water when they’re released at high volumes from the deep sea.

Since the Deepwater Horizon drilling rig exploded and sank into the Gulf of Mexico in late April, more than 200 million gallons of oil have gushed from the blown well.

The scientists also want to see how the oil breaks down into toxic and safer components in different ocean conditions, information that would help predict which ocean species are most at risk. The experiment also could provide data that would help in dealing with any future spills.

“Without this understanding, we’re no better off when the next one occurs,” said Ira Leifer, a researcher at the Marine Science Institute of the University of California at Santa Barbara who’s leading the team that’s proposed the experiment.

The plan calls for about two weeks of experiments with two research vessels and robotic vehicles at a cost of $8.4 million. The scientist would use monitoring equipment and sampling to conduct experiments at various levels in the water column.

Leifer said BP should pay for it, or the federal government should pay and send BP the bill.

The choice is really up to BP, he said.

“You can either let science happen and everyone wins, or you’re going to find yourself torpedoing that. It’s going to look bad in the history books when people look at it, and maybe in court,” Leifer said.

Scientists from universities, oceanic institutions and the National Oceanic and Atmospheric Administration have been tracking the layers of partly dissolved oil. NOAA has six research vessels in the Gulf working on assessing the damage from the spill.

Leifer said that while those researchers were looking for where the oil was, a larger experiment was necessary to test hypotheses and learn how to make better estimates.

It’s not clear whether any federal agency agrees.

The Department of Energy hasn’t been approached about the project, spokeswoman Stephanie Mueller said. Leifer has prepared an 88-page technical report, and he said he could get the experiment under way quickly. It’s not clear, however, whether any funding proposal could clear the necessary scientific review in time.

Leifer said he hoped that BP would see it as in its own interest to fund the study.

BP didn’t respond to queries.

Rep. Edward Markey, D-Mass., wrote to BP on June 10 asking for funding for a simpler, earlier version of Leifer’s plan. Markey said through a spokesman that it “could help answer some of the fundamental questions about this catastrophe and help us prepare should there be a next one. It is worth serious consideration by BP.”

Leifer’s team is made up of 15 experts on oil and gas in the ocean. He and some of the others also worked on the federal government’s Flow Rate Technical Group, which was formed to get a better estimate of the size of the disaster. Leifer said the group did the best it could with limited data provided by BP. The latest official estimate is that 35,000 to 60,000 barrels a day are flowing from the runaway well.

Leifer’s proposed experiment could help improve the estimate, but because the flow amount can change over time, it would still be impossible to come up with an accurate amount, he said.

“We’re trying to figure out not just how much is coming out, but where it’s going,” Leifer said. “The question is where is it going, why is it going there and what is it killing?”

The information also will help scientists predict what will happen when conditions change; for example, when the loop current shifts and temperatures rise.

McClatchy Newspapers reported July 2 that many experts say the overall scientific evaluation of the spill is surprisingly uncoordinated, as federal officials and BP have failed to mount a speedy, focused inquiry to understand its impact.

Leifer has dubbed the new proposal “Deep Spill 2.” The first Project Deep Spill was an experiment off Norway in 2000 in which mixtures of crude oil, diesel oil and natural gas were released half a mile below the surface of the ocean to simulate a blowout. The study was a joint project by the U.S. Minerals Management Service and 23 oil companies.

Leifer was part of a Department of Energy-funded experiment last summer on a natural oil seep near the Deepwater Horizon site. The earlier experiment looked at the effects of methane seeping into the atmosphere.

“We want to repeat the effort much more thoroughly, because the stakes are much higher with the oil spill,” he said. “It would be inexcusable not to learn from this.”

Related posts:

1. Deepwater Horizon oil spill
2. Volcanic eruption boosts ocean life
3. BP stopped oil leak

“The concentration of detergents and other chemicals used to clean up sites contaminated by oil spills can cause environmental nightmares of their own,” says Terry Hazen, a  microbial ecologist in Berkeley Lab’s Earth Sciences Division who has studied such notorious oil-spill sites as the Exxon Valdez spill into Alaska’s Prince William Sound.

“It is important to remember that oil is a biological product and can be degraded by microbes, both on and beneath the surface of the water,” Hazen says. “Some of the detergents that are typically used to clean-up spill sites are more toxic than the oil itself, in which case it would be better to leave the site alone and allow microbes to do what they do best.”

The Deepwater Horizon oil rig leased by energy giant BP that exploded on April 20, is now estimated to be disgorging some 210,000 gallons of oil a day into the Gulf of Mexico. To contain the spreading oil slick and keep it from polluting the fragile ecosystems of the Gulf coast and the Mississippi delta, clean-up crews have deployed an array of chemical dispersants, oil skimmers and booms. They have also attempted to burn off some of the surface oil. Such aggressive clean-up efforts are fraught with unintended consequences, Hazen warns. He cites as prime examples the Amoco Cadiz and the Exxon Valdez disasters.

In 1978, an oil tanker, the Amoco Cadiz, split in two about three miles off the coast of Normandy, releasing about 227,000 tons heavy crude oil that ultimately stained nearly 200 miles of coastline. The spill-site was so large that only the areas of greatest economic impact were treated with detergents. Large areas in the more remote parts of the coast went untreated.

“The untreated coastal areas were fully recovered within five years of the Amoco Cadiz spill,” says Hazen. “As for the treated areas, ecological studies show that 30 years later, those areas still have not recovered.”

In March of 1989, the oil supertanker Exxon Valdez spilled 11 million gallons of crude oil into the Prince William Sound and impacted some 1,300 miles of coastline. It remains the largest oil spill in U.S. history. A combination of detergents and bioremediation were used in the clean-up. The detergents were nutrient rich, being high in phosphorous and nitrogen compounds. In addition, as part of the bioremediation effort, fertilizers were also used to promote microbial growth. After the first year, the treated areas were dramatically cleaner, Hazen says, but after the second year no improvements were observed. Long-term prospects for the treated area are grim.

“What happened was that we took an oligotrophic (low nutrient) environment, and added lots of nutrients to it to speed up the degradation of the oil, which we probably did,” Hazen says. “However, we upset the ecological balance of the system, which could not handle the influx of nutrients. As a result, the severe environmental damage resulting from the spill is expected to persist for decades to come.”

While improvements to detergents have been made, including some degree of biodegradability, they remain nutrient rich and in some cases more toxic to the environment than crude oil.

source: news center

Related posts:

1. Scientis propose big experiment to study Gulf oil spill
2. BP stopped oil leak

Today humanity is warned that  increasing emission of carbon dioxide in the  atmosphere will destroy human life and our cities before the end of this century unless we change our ways and reduce the present levels of carbon  dioxide. Yet,  beneath  our  feet  are  forces  of  change  far more destructive for the earth’s environment and all of its occupants than anything that human activity has done or can ever do. Toba was one of the biggest of all within the last two million years with a Volcanic Explosivity Index (VEI) of 8. It is now the model by which geologists assess worst-case scenarios for the future.

There  are  only  about  half  a  dozen  locations  around  the  world  where geologists   have    identified   super volcanoes. One    location   is in New Zealand, one in Japan, and one in Russia. In the United States there is one in Yellowstone National Park where there was an eruption of strength 8 on the VEI, about 640,000 years ago. That strength represents a tenth of Toba’s and a hundred times the strength of Krakatau. Although it’s VEI would only be one-tenth that of Toba, it would be disastrous. Tambora, an Indonesian volcanic eruption of 1815, was ten times stronger than Krakatau and only a tenth as strong as  the  ancient  Yellowstone  one  yet  it  caused  widespread  destruction  of life  and  agriculture  all  over  the  world.

Now it is clear that the dust cloud from the explosion, one that reached high into the atmosphere because it happened near the equator, reduced the amount of sunshine that could reach the earth. Ad the eruption occurred near the North Pole the atmospheric dust would have stayed at a lower level within the atmosphere.

Geneticists believe that Toba had a particularly catastrophic effect on humans who, 74,000 years ago, were still at an early stage of development. The population on Earth may have been reduced to a few thousand people, pushing humanity to the edge of extinction. The  evidence  for  the  catastrophic  reduction  of numbers around the time of Toba comes from an analysis of mitochondrial  DNA  that  revealed  a  limited  genetic  diversity,  far  lower  than  the known age of humans would indicate. The total numbers of humans in the years following Toba seemed to be no more than ten thousand. Not until 50,000 years ago, 20,000 years after Toba, was there evidence of a rapid and widespread increase in the numbers of humans. In order to test the validity of their calculations regarding humans, geneticists examined the mitochondrial DNA of chimpanzees to find out if they too had been victims of the same environmental disaster. The results were conclusive. They had experienced a bottleneck similar to human DNA.

Related posts:

1. Tambora – biggest eruption recorded
2. Argentinian lake maybe holds secret of life on Earth
3. Volcanic eruption boosts ocean life

Iceland sits on a large volcanic hot spot in the Atlantic’s mid-oceanic ridge. Eruptions, common throughout Iceland’s history, are often triggered by seismic activity when Earth’s plates move and when magma from deep underground pushes its way to the surface. Iceland’s Laki volcano that erupted in 1783, freeing gases that turned into smog was mentioned in one article before and now point is on Eyjafjallajokull volcano.

The last time Eyjafjallajokull erupted was in 1821, pouring tonnes of ash containing toxic fluoride gas into the atmosphere. It lasted not 24 hours, but 2 years until 1823, causing the deaths of many cattle and sheep through fluor poisoning. Eyjafjallajokull has had four eruptions in the last thousand years: in 920, 1612, 1821-1823 and now in 2010. All of the previous eruptions were precursors to more massive activity from the neighboring Katla volcano but as yet geologists have not registered any seismic activity. Katla, located under the massive Myrdalsjokull icecap, threatens disastrous flooding and explosive blasts when it blows.

Eyjafjallajokull, a glacier covering a volcano of 1,600 meters in height and with a crater of 3 to 4 km in diameter, started becoming unstable at the end of 2009, when a number of small earthquakes fueled by building pressure seven kilometers beneath the volcano gave rise to a peak in activity – 3,000 earthquakes were registered between March 3 and 5 this year. This in turn was followed by an eruption on March 20.

There were two further eruptions on April 13 and 14, under the glacier causing meltwater floods to force the evacuation of 800 people from the slopes. From Wednesday to Thursday a huge cloud of ash, which continues to billow from the volcano, spread eastwards, causing flights to be cancelled across Western and Northern Europe.

Apart from reducing visibility and affecting flight control mechanisms, volcanic ash can damage the engines of aircraft and according to international regulations, the risk is sufficiently high to merit a closing of air space. An aircraft engine takes in air, compresses it and turns it into thrust by expelling it at high speed. If the air is mixed with particles of ash, it can clog hydraulic and electronic systems.

The last time this volcano erupted in 1821-1823, sheep and cows on its slopes were killed by toxic fluoride gas which also affects horses and humans. Easily absorbed through the skin or eyes, a quantity as small as 28 mg per kilo of body mass is fatal. It is currently not possible to predict how long the ash cloud will remain over Europe’s skies, especially because if the volcano continues to spew forth tonnes of material every hour, the situation can only worsen if the wind continues to push the plume eastwards.

Related posts:

1. Volcanic eruption boosts ocean life
2. Tambora – biggest eruption recorded
3. Volcanoes and global warming

This cannot go on safely as current rates may even mirror those of the “big five” mass extinctions of the past half-billion years, including the meteorite strike that did for the dinosaurs. While the world carried on after those events, it was massively transformed. To avoid a repeat, some scientists suggest a safe long-term annual extinction rate of no more than 10 per million species per year. By that measure humanity has already entered deep into a danger zone, if the current extinction rate is sustained.

Conclusion is that we are driving species to extinction by ploughing up or paving over their habitats, by introducing alien species like rats and weeds, by poisoning them with pollution, by hunting them for food and increasingly, by changing the climate.

Related posts:

1. Sulphur dioxide cooling Earth
2. Nitrogen and Phosphorus cycles
3. What about acid oceans?

Charles F. Richter invented scale for measuring an earthquakes in 1934. The Richter magnitude is measured from the amplitude of the largest seismic wave recorded by the earthquake, regardless of the type of strongest wave.

The Richter scale is logarithmic scale (base 10). This means that each whole number you go to the Richter scale, the amplitude of the ground motion recorded by seismograph goes up ten times. Using this scale, the earthquake of magnitude 7 would be ten times the level of ground vibration under earthquake of magnitude 6 (and 32 times more energy is released). A magnitude 8 earthquake releases as much energy and detonation of 6 million tons of TNT. Pretty impressive, is’n it? Fortunately, most of the earthquakes that occur each year are magnitude 2.5 or less, not enough for that most people to feel it.

The Richter magnitude scale is designed to describe small magnitudes earthquakes and they are expressed in negative numbers. This scale also has no upper limit, so it can describe earthquakes of unimaginable and (so far) unexperienced intensity, such as magnitude 10, 11 and above.

Another scale used to measure the strength of earthquakes is Mercalli scale. It was invited in 1902. by Guiseppe Mercalli and main difference between those two scales is that Mercalli scale uses observations of people who experienced the earthquake. This scale is not yet considered as scientific as the Richter, though.

The Mercalli scale isn’t considered as scientific as the Richter scale, though. Some witnesses of the earthquake might exaggerate just how bad things were during the earthquake and you may not find two witnesses who agree on what happened; everybody will say something different. The damage caused by the earthquake may not accurately show how strong it was because building design. distance from the epicenter and type of material the buildings rest on may significaly change level of destruction.

Magnitude of earthquake:

• less than 3.5 – generally not felt but recorded
• 3.5 to 5.4 – often felt but rarely causes damage
• less than 6.0 -  can cause slight damage
• 6.1 to 6.9  – can be destructive in area of 100km
• 7.0 to  7.9  – can cause serious damage over large areas
• 8 or greater can cause serious damage in areas several hundred km across

Picture below shows places on earth where some earthquakes occurred during the past.

Related posts:

1. 10 strongest earthquakes in modern history
2. Tsunami explained
3. Toba, supervolcano in Indonesia