Many of the largest explosive eruptions in Iceland involve a viscous, high-silica magma called rhyolite, and are driven by volcanic gases (mostly water and carbon dioxide). It is these gases that give a volcanic eruption its fizz. At depth these gases are dissolved within the magma, but as the magma rises towards the surface during an eruption, the gases expand dramatically, causing the magma to froth and accelerate upwards as a foam. The viscous rhyolite foam breaks down into tiny ash fragments which form the ash clouds.
Previously scientists had thought that Icelandic magma was less fizzy than those from Pacific Ocean volcanoes and expected much less explosive eruptions by comparison. However, this new research suggests some Icelandic volcanoes could produce eruptions just as explosive as those in the Pacific Rim. "I was amazed by what I found. I measured up to five per cent of water in the inclusions, more than double what was expected for Iceland, and similar in fact to the values for explosive eruptions in the Pacific 'Ring of Fire'. We knew the Torfajökull volcanic eruption was huge – almost 100 times bigger than recent eruptions in Iceland - but now we also know it was surprisingly gas-rich."
The finding helps explain why thin blankets of fine ash from older powerful Icelandic eruptions are found in peat bogs and lake beds across the UK and Europe. By accurately measuring the original gas content of Icelandic explosive eruptions for the first time, the research shows how Icelandic volcanoes have the power to generate the fine ash capable of being transported long distances and cause disruption to the UK and Europe.
"We know that large explosive eruptions have occurred at infamous volcanoes such as Hekla and Katla, but it is important also to appreciate that large explosive eruptions are also produced by less well-known Icelandic volcanoes such as Torfajökull and Öraefajökull."
"The discovery is rather worrying, as it shows that Icelandic volcanoes have the potential to be even more explosive than anticipated. Added to this is the view of several eminent scientists that Iceland is entering a period of increased volcanic activity. Iceland's position close to mainland Europe and the north Atlantic flight corridors means air travel could be affected again."
why the kamikaze pilots wore helmets.**
Al McGuire
LARGEST QUAKES -
Live Seismograms - Worldwide (update every 30 minutes)
This morning -
5.0 SOUTHERN SUMATRA, INDONESIA
5.7 HINDU KUSH REGION, AFGHANISTAN
5.0 NEAR EAST COAST OF HONSHU, JAPAN
5.3 LUZON, PHILIPPINES
A few aftershocks continue in Iceland - largest so far today 3.4.
No quakes so far today in Canary Islands (a 3.8 in Spain)
Cluster of moderate quakes in DODECANESE ISLANDS -TURKEY BORDER REGION continues - several 2.2's so far today.
Yesterday -
4/3/13 -
5.3 PAPUA, INDONESIA
5.0 OFF EAST COAST OF HONSHU, JAPAN
5.4 MYANMAR
5.2 CENTRAL MID-ATLANTIC RIDGE
Lots of moderate aftershocks in Iceland - largest 4.2
Cluster continues in Canary Islands - largest 4.4
Cluster of moderate quakes in DODECANESE ISLANDS -TURKEY BORDER REGION continued - largest 2.9 (a pair of 4.2's in Crete, Greece)
VOLCANOES -
Volcano Webcams
Volcano erupts in North Sulawesi, Indonesia - Mount Lokon in Indonesia's central North Sulawesi province erupted Wednesday, spewing ash to the sky and volcanic materials around the slope.
Etna (Sicily, Italy) - The 9th paroxysm from the New SE crater in 2013 occurred Wednesday afternoon. It has reached its peak phase with lava fountains, and lava flows from the fissure vent of the New SE cone descending into Valle del Bove. It seems that the fountains are much smaller ("only" 2-300 m) compared to those of the last eruption on 16 March, but the peak phase lasted longer this time.
Sandstone xenoliths from 16 Mar eruption: Closer inspection of the "white lava" reported in Tuesday's news revealed that these were so-called xenoliths, i.e. no lava at all, but pieces of sedimentary rock from strata underlying the volcano brought up by the rising magma.
In this case, they are pieces of barely compacted beach sandstone, similar to the xenoliths ejected during the flank eruptions in 2011 and 2012, which are believed to have trapped a different (so-called eccentric) shallow magma chamber beneath the volcano. To find such xenoliths as produces of eruptions from the SUMMIT craters is HIGHLY UNUSUAL and could (*speculation*) indicate that the latest, violent, eruptive episode has actually involved a different magma reservoir as well. Fresh snow has now covered much of the bombs from the recent eruption. (photos)
TROPICAL STORMS -
No current tropical storms.
SEVERE RAIN STORMS, FLOODING, LANDSLIDES -
Argentina - Flash flooding has affected at least 350,000 people. The government in Argentina has declared three days of national mourning after flash floods killed 54 people.
ONE OF THE HEAVIEST STORMS EVER RECORDED moved through the province hitting both the capital, Buenos Aires, and the city of La Plata. At least 48 people were killed in La Plata and six others in Buenos Aires. The provincial governor said La Plata had "never seen anything like it".
More bodies were being found as flood waters receded. Around 40cm (16in) of rain fell on La Plata in a short period late on Tuesday night and the early hours of Wednesday. Buenos Aires had earlier been hit by more than 15cm of rainfall. Thousands of people have been moved from their homes.
Residents have described spending nights on rooftops to escape the deluge while the coastguard used boats to help people who were stranded. Dozens of people looted a supermarket in La Plata, while others blocked roads demanding greater assistance from the authorities.
Many of those who died in La Plata were drowned or electrocuted after taking shelter in their cars in the suburb of Tolosa. "We are giving priority to rescuing people who have been stuck in trees or on the roofs of their homes." The city's oil refinery was flooded and then had to close due to a fire. YPF, the company which runs the facility, said "an extraordinary accumulation of rainwater and power outages in the entire refinery complex" caused the fire.
In Buenos Aires, one of those who died was a worker for the city's underground system who was electrocuted while trying to pump water from a flooded station. About 350,000 people have been affected by the torrents of rain. Thousands of cars were carried away by floods and hundreds of families had to be evacuated from their homes.
The city authorities said it was THE HEAVIEST APRIL RAINFALL IN A CENTURY. More rain was expected to fall before the weather cleared on Thursday. Photos
EXTREME HEAT & DROUGHT / WILDFIRES / CLIMATE CHANGE -
USDA planning ahead due to drought conditions in U.S. - The drought conditions could continue through spring and summer. “We still have an issue with drought. Over 50% of the lower 48 states is currently in the middle of extreme drought."
Sierra snow half normal after dry early 2013 - Consecutive dry winters in the Sierra are setting the stage for another summer drought across much of western and northern Nevada. Following significant snowfall in January, it turned into SOME OF THE DRIEST WEATHER ON RECORD during the last two months.
Chinese experts expect drought to last until May - The severe drought in parts of northwestern and southwestern China is likely to continue into May because of the hot, dry weather, authorities said. Higher temperatures and low rainfall are forecast for those regions this month and next.
Australia - Warning: land of more drought and flooding rains on the horizon. This sunburnt country will become a land of worse droughts and more frequent flooding rains as climate change continues, according to a new report from the Climate Commission.
"The southeast of Australia, including many of our largest centres, stands out as being at increased risk from many extreme weather events - heatwaves, bushfires, heavy rainfall and sea-level rise."
Drought fears drive Monsanto profit - Monsanto reported a stronger than expected 22 per cent jump in quarterly earnings as US farmers' fear of a repeat of last year's drought and continued strength from its Latin America business bolstered demand for its genetically modified seeds.
HEALTH THREATS -
Two more H7N9 cases cited; virus may be adapting to mammals - Chinese authorities reported two more human illnesses caused by the H7N9 avian influenza strain Wednesday, one of them fatal, as experts said genetic evidence suggests that the virus may be starting to adapt to mammals.
RECALLS & ALERTS
