Stopping Lava

There's no denying it - it is a hard job to stop lava from flowing where it wants to flow.  Many have tried, but few have succeeded.  The Americans are having to consider this again as an eruption of Kīlauea (one of the most active volcanoes in the world) is starting to threaten properties and roads on the Big Island of Hawaii.  There are a range of strategies that could be used; none of them are cheap and none are guaranteed to be effective.  Have a look at the range of options that could be employed- which do you think would be best to use?

Earthquakes from Space

A new European satellite has given us a new way to monitor the impact of earthquakes.  Sentinel measure the small changes in the position of parts of the Earth's crust by comparing 'before' and 'after' images of an area that has experienced an earthquake.  Analysis of these results can show where stresses in the crust are being concentrated which may allow for predictions to be made about the location of subsequent tremors. 

In the search to find a method of effectively predicting seismic events, any new tool that can contribute has to be welcomed.

Badaboom Volcano

Over the last few weeks you may have noticed that one of Iceland's many volcanoes has been getting more active, generating hundreds of volcanoes in a day.  Bárðarbunga is one of the volcanoes underneath the huge ice sheet of  Vatnajökull and though it is a mafic eruption it does have the potential to create similar aviation problems that Eyjafjallajökull caused in 2010 because of its similar sub-glacial setting.  So far there has been a little ash and a fissure eruption as a dyke reached the surface.  The aviation warnings  have fluctuated from yellow to orange and then back again.  Perhaps the bigger hazard is from a jökulhlaup that can be triggered by the melting of the glacial ice from the volcano's heat.  It will be worth keeping an eye on what's happening with this.  

For the latest updates, check out the website of the Icelandic Meteorological Office.

Did you feel it?

We had an earthquake today!  A magnitude 4.1 tremor with its epicentre in the Bristol Channel, just north of Ilfracombe was recorded by the British Geological Survey at 1.21pm.

No reports of damage yet, not even knick-knacks falling! Have a look at a 'VI' on the Mercalli Intensity scale.

That sinking feeling

We seem to be experiencing a spate of sinkholes suddenly appearing in places around the UK.  They are the result of caves collapsing as the rock that support their roofs is undermined by erosion.  They have appeared several times on the news and there has been an explanation of their formation by a geologist from the BGS.  The rise in groundwater levels caused by the recent heavy rains combined with geological vulnerability of certain rocks (chalk and gypsum are particularly vulnerable) make these hazards sudden and unpredictable.  Security camera footage from the National Corvette Museum in the US shows a hole forming.

The Vale of Glamorgan does suffer from sinkholes as well because our bedrock geology here is mostly limestone.  How solid is the ground under your feet?

Seismic Puzzle

The earthquake hazard map of the USA has a major seismic puzzle.  It's not the high hazard in California (CA) caused by the San Andreas Fault or in Washington (WA) and Alaska (AK) easily explained by the occurrence of subduction zones around the Pacific Ring of Fire.  There is another high hazard zone along the Mississippi River further east.

Harri P in Year 12 drew my attention to this odd occurrence of earthquakes thousands of kilometres from a plate boundary.  There have been some major seismic events in this region, in particular the magnitude 7 New Madrid earthquakes of 1811-12.  The cause of these 'quakes was a puzzle until a few years ago when a team of geologists from the University of Quebec discovered a slab of crust that is descending into the mantle, disrupting the flow of the mantle and the crust in this area.  It is similar in some ways to a subduction zone but without the fold mountains, trench and volcanoes.  It does pose a continuing danger of creating major earthquakes.

It is a very strange phenomenon and goes to show just how much we still have to discover about how the crust and the mantle work.

Eruption!

Mt Kelud on the Indonesian island of Java has erupted.  It has produced a lot of ash, but so far hasn't erupted explosively.   Indonesia is the 'Volcano Nation' It is the latest in a long line of Indonesian volcanoes to erupt as the Indo-Australian Plate gets subducted underneath the Eurasian Plate.  You can see pictures of the eruption and its effects here.

Eruption!

Mt Sinabung has erupted.  It is a volcano on the Indonesian island of Sumatra that has been showing signs of activity for a while.  It is unfortunate that an evacuation in September finished on Friday with the result that the death toll as I write this is 14 people.  It does show the dangerous unpredictability of volcanoes.  You can see photos of the eruption here.

Lucky or unlucky?

This farmer lost his barn but the boulders that fell in a landslide missed his house.  The family living there were also unharmed.  Have a look at all the photographs of the scene and you can see how lucky the family were.  This is a normal slope-forming process however when people get in the way of these geomorphological changes, problems can occur.

Work experience opportunity

An opportunity for a week's work experience is being offered to Year 12 geology students who are intending to study geology at university level.  The placement will be during the week allocated for work experience in July.

If you are interested in this opportunity you should write a letter of application, addressed to Ms Bethan Gallimore setting out your previous experience in geology, your interests and future plans in the subject.  You should also consider the work that SRK do.

Application letters must be emailed to Mr Walsh by 3.15 on Friday 31st January.  The final decision about the placement will be made by the staff at SRK. 

If you have any questions, please speak to Mr Walsh.

SRK

No trigger required

Most volcanoes need some kind of external event to trigger an eruption.  Often an earthquake on a fault will create a weakness that allows the pressure to escape.  Supervolcanoes, whose eruptions can be cataclysmic, were always a bit of a puzzle when it came to working out what set them off.  However a team of Swiss geologists have discovered that they don't need a trigger.  Their size alone is enough to generate enough pressure in the magma to generate an eruption.  Though this may be a little worrying, supervolcanoes have long time gaps between eruptions - roughly 100,000 years.  Of course we don't know exactly when in that time period the big bang will happen....

Subsiding away

Just outside the village of Foolow (yes there really is a place called that) in Derbyshire one of the consequences of old mining activity has been revealed in the landscape.  A 50 metre wide sinkhole has opened up with the subsidence of some old fluorite mines.  The limestone of the south of Derbyshire was heaviliy mineralised with hydrothermal veins of lead and copper ores and with fluorite (including the famous and rare variety of Blue John).  The legacy of this mining can still clearly be seen in the landscape and it continues to throw up surprising events such as this.  It does show the importance of engineering modern mines to prevent such problems in the future.

There clearly wasn't much going on in Derbyshire over the Christmas holidays though as the Police had to warn people to stay away as crowds were gathering to watch a big hole in the ground.

Reminder from the "Ring of Fire"

Most of the world's volcanoes are found around the rim of the Pacific Ocean and every so often one of these volcanoes bursts into activity, just as a reminder about the tectonic instability that creates all this volcanic activity.  Chaparrastique, a volcano in El Salvador, has erupted for the first time since 1976.  It isn't a particularly big eruption with the production of hot ash causing the evacuation of surrounding settlements.  Overall it isn't a big event, but it does give us all a reminder about the ever-present potential for volcanic and seismic disaster around the "Pacific Ring of Fire".

It is worth checking out the news story for the video showing the eruption and its plate tectonic setting.

Half the UK

The investigation into shale gas continues with an intial assessment of the potential of Britain's geology for shale gas exploitation.  A report produced for the Department of Energy and Climate Change estimates that up to half of the UK could have suitable geology.  This isn't too much of a surprise, as shale is the most common sedimentary rock and hasn't featured as a strategiec resource for the country in the past.

The resource is there, the question remains whether the economics, energy security and environmental demands can all be made to balance.  What do you think?

How big???!!!???

Yellowstone is a big volcano - a really big volcano - so big a volcano we call it a supervolcano.  It turns out that Yellowstone is actually much bigger than we had previously thought - 2.5 times bigger according to Professor Bob Smith from the University of Utah.  This means that the magma chamber contains a staggering 200-600 cubic kilometres of molten rock.

Seismic surveys of the volcano have reavealed the true extent of the magma source, created by a sub-continental hot spot.  Don't worry too much though, supervolcanoes don't erupt very frequently and Yellowstone doesn't look like it will erupt imminently....probably.

You can check out the Yellowstone Volcano Observatory and assess the risk yourself.

Waiting for "The Big One"

Los Angeles will be struck by a devastating earthquake.... soon.  We don't know when but we do know that it will happen.  By recording the earthquakes along the San Andreas Fault for nealry the last 200 years it is very apparent that through the 20th century the fault hasn't moved much comapred to the frequent earthquakes along the fault during the 19th Century.  Contrary to what many people would think, geologists know that this is a "bad thing" because if the fault is locked, energy is being built up in the fault so that when it moves it will move a lot.

At the American Geophysical Union conference in San Fransisco, geoscientists from the US Geological Survey have been posing the question "is LA ready for a megaquake?"

Read through the article, do you think that they can cope with a shock on the scale predicted?

Cow dung bomb

There are some words in geology that graphically describe features we see in the rock, but few are quite as illustrative as cow dung bomb (sometimes known as a cow pat bomb).  It is a type of volcanic bomb - igneous rock ejected from a volcanic eruption but t does have an unusual form resembling .... well you can guess.  Most volcanic bombs cool in the air, creating a distinctive aerodynamic shape (see below).  Cow dung bombs are more liquid and actually land still largely molten, giving them their distinctive shape.

Where do you think we could find cow dung bombs?

An island is born

 

Every so often a volcano erupts out of the ocean to form a new island.  The most famous of these is an island called Surtsey, close to Heimaey off the south coast of Iceland.  Since it emerged in 1963 it has been intensively studied by geologists and biologists to investigate rates of erosion and colonisation of new landmasses.

 

This formation of a new island has happened again, this time off the coast of Japan.  Video of the eruption (taken from planes flying over the volcano) clearly show the volcanic processes that have built the volcano to such an extent it has grown above sea level.

Etna Erupts

Europe's most active volcano is at it again.  Eruptions over the weekend had lava fountains lighting up the night sky over Sicily.

Despite the frequency of volcanic activity, Etna poses little risk to surrounding setlements because of the mafic composition of its magma.  It does put on a good show though.

7.2

The Philippines suffered an earthquake with a magnitude of 7.2 today.  This slideshow of photographs shows the impact of an earthquake of this size.

You can get an update on the latest developments by checking out the earthquake report.