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Aurora Australis lighting up Tasmanian Skies….During recent years, the Aurora Australis has created an amazing light show over Tasmania, Australia.Auroras are caused when charged particles enters the earth’s atmosphere. The solar activity cycle has just passed its approximate peak, so the last couple years have been some of the best for Aurora viewing and photographing in the last decade.The Aurora Australis is centred on the Earth’s South Magnetic Pole, which is not a fixed point like the Geographic South Pole – and because of this Hobart is uniquely placed to see it (1)NBReferences1) http://www.abc.net.au/local/stories/2012/02/28/3441638.htmFurther Readinghttp://www.universetoday.com/97718/once-in-a-lifetime-image-emperor-penguins-under-the-aurora-australis/http://www.smh.com.au/technology/sci-tech/major-solar-flare-erupts-from-the-sun-20121024-2848h.htmlhttp://www.afr.com/p/national/hobart_makes_lonely_planet_top_cities_vL2qLG7Fuc0aaH3SKVAMyIPhotograph: The Aurora Australis covers the sky. Courtesy of Leonard Low (audience submitted photograph - http://www.abc.net.au/local/stories/2012/07/18/3548513.htm)

Aurora Australis lighting up Tasmanian Skies….

During recent years, the Aurora Australis has created an amazing light show over Tasmania, Australia.

Auroras are caused when charged particles enters the earth’s atmosphere. The solar activity cycle has just passed its approximate peak, so the last couple years have been some of the best for Aurora viewing and photographing in the last decade.

The Aurora Australis is centred on the Earth’s South Magnetic Pole, which is not a fixed point like the Geographic South Pole – and because of this Hobart is uniquely placed to see it (1)


NB


References
1) http://www.abc.net.au/local/stories/2012/02/28/3441638.htm

Further Reading
http://www.universetoday.com/97718/once-in-a-lifetime-image-emperor-penguins-under-the-aurora-australis/
http://www.smh.com.au/technology/sci-tech/major-solar-flare-erupts-from-the-sun-20121024-2848h.html
http://www.afr.com/p/national/hobart_makes_lonely_planet_top_cities_vL2qLG7Fuc0aaH3SKVAMyI
Photograph: The Aurora Australis covers the sky. Courtesy of Leonard Low (audience submitted photograph - http://www.abc.net.au/local/stories/2012/07/18/3548513.htm)

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Life without the sun
One of the most fascinating biological environments on Earth is found on the floor of the ocean. Kilometers below the surface, no light reaches these areas, so for life to exist, it must have a different energy source. This entire ecosystem is living off the energy of the Earth.
Rocks deep inside the earth contain elements in reduced form; they haven’t reacted with oxygen because there is no free oxygen inside the Earth. At places like mid-ocean ridges, the Earth itself brings these elements up to the surface and exposes them to the ocean. Life in these settings can take up some of these elements, like iron, react it with oxygen in the water, and use that energy to sustain itself. The scientist’s term for this life would be chemosynthetic – using chemistry to gain energy (contrast that term with photosynthetic, as plants are).

This entire seafloor is covered with white crabs (10 cm scalebar). There’s no reason for any of the organisms here to waste energy by coloring themselves; there’s no sunlight so nothing can be seen anyway. This is an area rich with a type of life very different from anything we’re familiar with in our lives up at the surface, almost 2500 meters above.
-JBB
"Dense mass of anomuran crab Kiwa around deep-sea hydrothermal vent" by A. D. Rogers et al. - A. D. Rogers et al. in PLoS Biology. Licensed under Creative Commons Attribution 2.5 via Wikimedia Commons -http://commons.wikimedia.org/wiki/File:Dense_mass_of_anomuran_crab_Kiwa_around_deep-sea_hydrothermal_vent.jpg#mediaviewer/File:Dense_mass_of_anomuran_crab_Kiwa_around_deep-sea_hydrothermal_vent.jpg

Life without the sun

One of the most fascinating biological environments on Earth is found on the floor of the ocean. Kilometers below the surface, no light reaches these areas, so for life to exist, it must have a different energy source. This entire ecosystem is living off the energy of the Earth.

Rocks deep inside the earth contain elements in reduced form; they haven’t reacted with oxygen because there is no free oxygen inside the Earth. At places like mid-ocean ridges, the Earth itself brings these elements up to the surface and exposes them to the ocean. Life in these settings can take up some of these elements, like iron, react it with oxygen in the water, and use that energy to sustain itself. The scientist’s term for this life would be chemosynthetic – using chemistry to gain energy (contrast that term with photosynthetic, as plants are).

This entire seafloor is covered with white crabs (10 cm scalebar). There’s no reason for any of the organisms here to waste energy by coloring themselves; there’s no sunlight so nothing can be seen anyway. This is an area rich with a type of life very different from anything we’re familiar with in our lives up at the surface, almost 2500 meters above.

-JBB

"Dense mass of anomuran crab Kiwa around deep-sea hydrothermal vent" by A. D. Rogers et al. - A. D. Rogers et al. in PLoS Biology. Licensed under Creative Commons Attribution 2.5 via Wikimedia Commons -http://commons.wikimedia.org/wiki/File:Dense_mass_of_anomuran_crab_Kiwa_around_deep-sea_hydrothermal_vent.jpg#mediaviewer/File:Dense_mass_of_anomuran_crab_Kiwa_around_deep-sea_hydrothermal_vent.jpg

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The Soufrière Hills volcanoThis is the beautiful Soufrière Hills Volcano, located on the Island of Montserrat. Beautiful, but deadly. The Soufrière Hills volcano is a very active, very complex stratovolcano. It began erupting in 1995 after a long period of slumber, and since waking it’s erupted continuously. The volcano is andesitic, and periods of dome growth and interjected with sudden explosive dome collapse, and dome collapse episodes result in pyroclastic flows, explosive eruptions and ash venting.Some geological history of the volcano is known, including an eruption around 2000BCE which formed the crater known as English’s crater, and an eruption in 1630 which ejected between 25 and 65 million cubic metres of lava.The eruptions have meant that half of the island of Montserrat are uninhabitable, and  the capital city on the Island- Plymouth- has been destroyed. This has meant around two-thirds of the islands population have relocated off of the island. Most of the settlements abandoned were done so due to pyroclastic flow. The volcano is one of the most closely studied in the world, and detailed study has led to geoscientists concluding that there are two interconnected magma chambers at play, the deeper 12km below the surface, and the shallower, 6km below. For more information head to the links below.-LLhttp://www.mvo.ms/http://www.bgs.ac.uk/discoveringGeology/hazards/volcanoes/montserrat/home.htmlhttp://www.volcanodiscovery.com/montserrat.htmlImage; Patrick Smith

The Soufrière Hills volcano

This is the beautiful Soufrière Hills Volcano, located on the Island of Montserrat. Beautiful, but deadly. The Soufrière Hills volcano is a very active, very complex stratovolcano. It began erupting in 1995 after a long period of slumber, and since waking it’s erupted continuously. 

The volcano is andesitic, and periods of dome growth and interjected with sudden explosive dome collapse, and dome collapse episodes result in pyroclastic flows, explosive eruptions and ash venting.

Some geological history of the volcano is known, including an eruption around 2000BCE which formed the crater known as English’s crater, and an eruption in 1630 which ejected between 25 and 65 million cubic metres of lava.


The eruptions have meant that half of the island of Montserrat are uninhabitable, and  the capital city on the Island- Plymouth- has been destroyed. This has meant around two-thirds of the islands population have relocated off of the island. Most of the settlements abandoned were done so due to pyroclastic flow. 

The volcano is one of the most closely studied in the world, and detailed study has led to geoscientists concluding that there are two interconnected magma chambers at play, the deeper 12km below the surface, and the shallower, 6km below. 

For more information head to the links below.

-LL


http://www.mvo.ms/

http://www.bgs.ac.uk/discoveringGeology/hazards/volcanoes/montserrat/home.html

http://www.volcanodiscovery.com/montserrat.html


Image; Patrick Smith

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Peatlands: aquatic regulatorsThis is a peat marsh or peatland found in Belarus. Peat marshes are locations dominated by soil layers known as, well, peat, a mixture of organic material in various states of decomposition, produced by centuries of plants growing and dying in the same location.Plants growing and dying on top of each other, like in this bog, will pile up thick layers of organic material mixed with large amounts of water. That soil will then serve as an anchor for additional plants to grow, stabilizing the water lines and the ecosystem over time. Those layers can then serve as homes for all sorts of additional plant and animal life, dependent on the stabilized peat layers.Peatlands are hugely important for mankind. They contain large amounts of stored organic carbon in them, so if they are damaged or destroyed, that carbon will rapidly release to the ecosystem and the atmosphere. Protecting peatlands therefore is a key step in fighting climate change.Peatlands in many areas are in fact under siege as they sit at areas where fresh water, like that found in a river, becomes stagnant. Draining peatlands can give water supplies useful for farming, electricity generation, and shipping, and can create land that people can build on. Every time this happens, the end result is going to be additional CO2 pumped into the atmosphere.These systems also serve as natural barriers against the weather. Peat bog soils can be up to 90% water, making them dense and capable of absorbing the force of storm surges and waves. Thick layers of peatlands can serve as natural protectors for cities upstream from hurricanes and typhoons, but only if they’re left in place. If the city upstream diverts the water that sustains them, the city may enjoy the water supply, but it also can put itself at greater risk from the oceans.-JBBImage credit: EGU Open Accesshttp://imaggeo.egu.eu/view/614/Read more:http://www.doeni.gov.uk/niea/biodiversity/habitats-2/peatlands.htmhttp://www.wetlands.org/Whatarewetlands/Peatlands/tabid/2737/Default.aspxhttp://www.peatsociety.org/peatlands-and-peat/what-peat

Peatlands: aquatic regulators

This is a peat marsh or peatland found in Belarus. Peat marshes are locations dominated by soil layers known as, well, peat, a mixture of organic material in various states of decomposition, produced by centuries of plants growing and dying in the same location.

Plants growing and dying on top of each other, like in this bog, will pile up thick layers of organic material mixed with large amounts of water. That soil will then serve as an anchor for additional plants to grow, stabilizing the water lines and the ecosystem over time. Those layers can then serve as homes for all sorts of additional plant and animal life, dependent on the stabilized peat layers.

Peatlands are hugely important for mankind. They contain large amounts of stored organic carbon in them, so if they are damaged or destroyed, that carbon will rapidly release to the ecosystem and the atmosphere. Protecting peatlands therefore is a key step in fighting climate change.

Peatlands in many areas are in fact under siege as they sit at areas where fresh water, like that found in a river, becomes stagnant. Draining peatlands can give water supplies useful for farming, electricity generation, and shipping, and can create land that people can build on. Every time this happens, the end result is going to be additional CO2 pumped into the atmosphere.

These systems also serve as natural barriers against the weather. Peat bog soils can be up to 90% water, making them dense and capable of absorbing the force of storm surges and waves. Thick layers of peatlands can serve as natural protectors for cities upstream from hurricanes and typhoons, but only if they’re left in place. If the city upstream diverts the water that sustains them, the city may enjoy the water supply, but it also can put itself at greater risk from the oceans.

-JBB

Image credit: EGU Open Access
http://imaggeo.egu.eu/view/614/

Read more:
http://www.doeni.gov.uk/niea/biodiversity/habitats-2/peatlands.htm
http://www.wetlands.org/Whatarewetlands/Peatlands/tabid/2737/Default.aspx
http://www.peatsociety.org/peatlands-and-peat/what-peat

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#Volcanofriday part 2Earlier today we covered the initiation of an eruption in Iceland. On the other side of the world, an eruption that is much more serious also is unfolding as I type this. This ash cloud is pouring out of the volcano known as Tavurvur on the island of New Britain, in the nation of Papua New Guinea.Tavurvur is part of a much larger volcanic complex known as the Rabaul Caldera that sits at the far northeastern tip of New Britain. This caldera is the remnants of several large volcanic explosions, the most recent of which took place 1400 years ago. A caldera is a giant hole in the ground; when a large magma chamber beneath the Earth’s surface empties during an eruption, it leaves empty space and the rocks above the magma chamber collapse downward, forming a huge crater in the ground.The Rabaul caldera is about 8 x 14 kilometers in size. On its southeastern slope, the rim of this caldera has been breached by the Pacific Ocean, flooding the caldera center and creating a natural harbor, protected from the open ocean by the eastern and northern walls of the caldera.This setup, a protected harbor, is a solid place for economic activity. By the early 1990’s, about 50,000 people lived on the coastline of this harbor, but the volcano had something to say about that.Calderas don’t die when they erupt. It can take thousands of years for their magma chambers to rebuild, but the magma supply doesn’t shut off after large eruptions. Typically, small volcanoes will begin growing on the edges of the caldera what is known as the resurgent phase of caldera activity. Tavurvur is one of these volcanoes. In 1994 it erupted simultaneously with another cone known as Vulcan on the volcano’s rim, decimating the area. Thankfully, the population was mostly evacuated the night before the eruption as earthquakes gave an early warning, leading to only 5 deaths, but today the population of the area today is a small fraction of what it was before these eruptions.Tavurvur rumbled to life again today, sending ash clouds high into the air and producing fountains of lava. There is video of the eruption up at our blog,http://the-earth-story.com/ This volcano is a direct hazard to many more people on the ground than the current eruption in remote Iceland, and has also caused aviation alerts and forced the redirection of some flights due to ash in the air.-JBBImage credit: Oliver Bluett/AFPhttp://www.washingtonpost.com/news/morning-mix/wp/2014/08/29/photos-in-papua-new-guinea-mount-tavurvur-explodes-in-spectacular-style/Read more:http://volcano.oregonstate.edu/oldroot/volcanoes/rabaul/rabaul.htmlhttp://www.volcanodiscovery.com/rabaul-tavurvur.htmlhttp://abcnews.go.com/International/papua-guineas-tavurvur-volcano-erupts/story?id=25171482http://www.theguardian.com/world/2014/aug/29/papua-new-guinea-volcano-erupts-diverting-some-international-flights?cmp=wp-pluginhttp://www.wired.com/2008/10/volcano-profile-rabaul/

#Volcanofriday part 2

Earlier today we covered the initiation of an eruption in Iceland. On the other side of the world, an eruption that is much more serious also is unfolding as I type this. This ash cloud is pouring out of the volcano known as Tavurvur on the island of New Britain, in the nation of Papua New Guinea.

Tavurvur is part of a much larger volcanic complex known as the Rabaul Caldera that sits at the far northeastern tip of New Britain. This caldera is the remnants of several large volcanic explosions, the most recent of which took place 1400 years ago. A caldera is a giant hole in the ground; when a large magma chamber beneath the Earth’s surface empties during an eruption, it leaves empty space and the rocks above the magma chamber collapse downward, forming a huge crater in the ground.

The Rabaul caldera is about 8 x 14 kilometers in size. On its southeastern slope, the rim of this caldera has been breached by the Pacific Ocean, flooding the caldera center and creating a natural harbor, protected from the open ocean by the eastern and northern walls of the caldera.

This setup, a protected harbor, is a solid place for economic activity. By the early 1990’s, about 50,000 people lived on the coastline of this harbor, but the volcano had something to say about that.

Calderas don’t die when they erupt. It can take thousands of years for their magma chambers to rebuild, but the magma supply doesn’t shut off after large eruptions. Typically, small volcanoes will begin growing on the edges of the caldera what is known as the resurgent phase of caldera activity. Tavurvur is one of these volcanoes. In 1994 it erupted simultaneously with another cone known as Vulcan on the volcano’s rim, decimating the area. Thankfully, the population was mostly evacuated the night before the eruption as earthquakes gave an early warning, leading to only 5 deaths, but today the population of the area today is a small fraction of what it was before these eruptions.

Tavurvur rumbled to life again today, sending ash clouds high into the air and producing fountains of lava. There is video of the eruption up at our blog,http://the-earth-story.com/ 

This volcano is a direct hazard to many more people on the ground than the current eruption in remote Iceland, and has also caused aviation alerts and forced the redirection of some flights due to ash in the air.

-JBB

Image credit: Oliver Bluett/AFP
http://www.washingtonpost.com/news/morning-mix/wp/2014/08/29/photos-in-papua-new-guinea-mount-tavurvur-explodes-in-spectacular-style/

Read more:
http://volcano.oregonstate.edu/oldroot/volcanoes/rabaul/rabaul.html
http://www.volcanodiscovery.com/rabaul-tavurvur.html
http://abcnews.go.com/International/papua-guineas-tavurvur-volcano-erupts/story?id=25171482
http://www.theguardian.com/world/2014/aug/29/papua-new-guinea-volcano-erupts-diverting-some-international-flights?cmp=wp-plugin
http://www.wired.com/2008/10/volcano-profile-rabaul/

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libutron:

Coyamito Agate Pseudomorph | ©Uwe Reier
Rancho Coyamito Norte, Mexico (2013).
Pseudomorphs in agate are quite rare but do occur in nodular agates from various locations, usually as a calcite or aragonite replacement. 

libutron:

Coyamito Agate Pseudomorph©Uwe Reier

Rancho Coyamito Norte, Mexico (2013).

Pseudomorphs in agate are quite rare but do occur in nodular agates from various locations, usually as a calcite or aragonite replacement. 

Video

This is amateur video taken earlier today of the beginnings of an eruption of the volcano Tavurvur on the island of New Britain in the nation of Papua New Guinea. 

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Earth’s deepest earthquakesNormally, Earthquakes are a shallow phenomenon, confined to Earth’s upper ~20 kilometers. There are only a couple places where earthquakes take place any deeper than that; subduction zones.Based on its physical properties, the outer portion of the Earth can be divided into two layers, the lithosphere and the asthenosphere. The lithosphere is the outermost layer of the planet, including the crust, and it is cold. So cold, in fact, that it is able to break and fracture.The asthenosphere, deeper in the planet, is warm. Warm enough, in fact, that the rocks are able to move and flow without breaking. Apply a force to a rock this hot and, over geologic time, it will flow like a glacier or like silly putty. For an earthquake to happen, the rocks have to be cold enough to break. If they can flow, they won’t fracture and there won’t be any earthquakes. The boundary between the lithosphere and the asthenosphere is the deepest depth that an earthquake can happen at, unless cold material is taken down deeper into the mantle.That’s exactly what happens at subduction zones, where old, cold, oceanic plates are taken down into the mantle. Those rocks have been at the surface for hundreds of millions of years and they take time to warm up. They stay cold up to hundreds of kilometers deep into the Earth, and during this portion of their voyage they continue producing earthquakes. Scientists using seismometers can locate these earthquakes and actually track that they get deeper farther from the subduction zone. This layer of deep earthquakes within sinking plates is known as the Wadati-Benioff zone, after two geophysicists, and is a solid demonstration of how subduction zones work. These earthquakes let us see where the plates are as they sink.-JBBImage credit: Marshak, Essentials of Geology, licensed to me for teaching purposes

Earth’s deepest earthquakes

Normally, Earthquakes are a shallow phenomenon, confined to Earth’s upper ~20 kilometers. There are only a couple places where earthquakes take place any deeper than that; subduction zones.

Based on its physical properties, the outer portion of the Earth can be divided into two layers, the lithosphere and the asthenosphere. The lithosphere is the outermost layer of the planet, including the crust, and it is cold. So cold, in fact, that it is able to break and fracture.

The asthenosphere, deeper in the planet, is warm. Warm enough, in fact, that the rocks are able to move and flow without breaking. Apply a force to a rock this hot and, over geologic time, it will flow like a glacier or like silly putty. 

For an earthquake to happen, the rocks have to be cold enough to break. If they can flow, they won’t fracture and there won’t be any earthquakes. The boundary between the lithosphere and the asthenosphere is the deepest depth that an earthquake can happen at, unless cold material is taken down deeper into the mantle.

That’s exactly what happens at subduction zones, where old, cold, oceanic plates are taken down into the mantle. Those rocks have been at the surface for hundreds of millions of years and they take time to warm up. They stay cold up to hundreds of kilometers deep into the Earth, and during this portion of their voyage they continue producing earthquakes. Scientists using seismometers can locate these earthquakes and actually track that they get deeper farther from the subduction zone. This layer of deep earthquakes within sinking plates is known as the Wadati-Benioff zone, after two geophysicists, and is a solid demonstration of how subduction zones work. These earthquakes let us see where the plates are as they sink.

-JBB

Image credit: Marshak, Essentials of Geology, licensed to me for teaching purposes

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Lava waterfall
When a new eruption breaks through at Kilauea volcano, lava tends to pour out of rift zones and small cones, covering the entire surrounding area.
Kilauea is full of cracks and craters, including old pit craters created when the ground collapsed after a buried magma reservoir emptied. When a volcanic eruption breaks through near one of these pit craters, the lava is going to flow to the lowest place it can find. If there’s a pit crater in the way, the lava is going to pour into the pit crater.

This lava waterfall was formed in 1969 during the eruption at Mauna Ulu, the small cone on Kilauea’s East Rift Zone seen in the distance. The lava poured out over the landscape, burning away trees, and then reached the nearby Aloi crater, where it cascaded over the walls and down to the crater floor.
-JBB
Image credit: Don Swanson, USGShttps://www.flickr.com/photos/usgeologicalsurvey/14802198589/

Lava waterfall

When a new eruption breaks through at Kilauea volcano, lava tends to pour out of rift zones and small cones, covering the entire surrounding area.

Kilauea is full of cracks and craters, including old pit craters created when the ground collapsed after a buried magma reservoir emptied. When a volcanic eruption breaks through near one of these pit craters, the lava is going to flow to the lowest place it can find. If there’s a pit crater in the way, the lava is going to pour into the pit crater.

This lava waterfall was formed in 1969 during the eruption at Mauna Ulu, the small cone on Kilauea’s East Rift Zone seen in the distance. The lava poured out over the landscape, burning away trees, and then reached the nearby Aloi crater, where it cascaded over the walls and down to the crater floor.

-JBB

Image credit: Don Swanson, USGS
https://www.flickr.com/photos/usgeologicalsurvey/14802198589/

Photoset

#VolcanoFriday

On Friday morning (local time in both areas), a pair of volcanoes a world apart acted up. First, let’s note developments in Iceland.

For the past several weeks, scientists have been watching the Bardarbunga (Bárðarbunga) volcanic system rumble to life in Iceland. It has produced a series of earthquakes as well as likely at least one small eruption buried beneath the large Vatnajökull ice sheet. A dense seismic network in the area, built by scientists from Iceland and a team from Cambridge University, was able to readily detect the locations of these earthquakes, allowing us to see this pattern. Over the past week, earthquake locations beneath the volcano migrated northeast, from the Bardarbunga system towards a different volcano, Askja. 

The earthquakes formed a linear pattern when projected onto the surface, indicating the growth of a dike. Dikes are a typical structure created by magma rising up through the earth; when rocks are put under tension, they typically break and form long, linear planes just like faults. In this case, this crack was being formed by magma pushing the rocks apart as it rose up.

Friday morning, a small outpouring of lava began as this crack reached the surface. When a dike reaches the surface, it tends to produce a long chain of volcanic centers known as a fissure eruption; this eruption is a small fissure at present. The black and white image attached to this post is from one of several webcams in the area that caught the magma arriving at the surface.

The eruption is in a remote area of Iceland and as of now has produced very little ash. It didn’t erupt beneath the icecap this time, so there is little interaction between the lava and ice. However, with a new eruption, the Icelandic authorities have widened the zone of alert for overflying aircraft to encompass a large portion of the island’s interior.

I’ve posted video from an early overflight of the volcano this morning at our blog, http://the-earth-story.com/post/96085322821/video-from-a-plane-overflight-of-the-opening.

-JBB

Image credits: Icelandic Meteorological Office
http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2949
http://www.zerohedge.com/news/2014-08-28/fissure-eruption-begins-iceland-bardarbunga-magma-breaches-surface