Category Archives: update

OUGS Talk; John Murray on Etna

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One of the perks of studying geoscience with the Open University is it has a very active Geological Society. Although I joined and went to the odd talk towards the start of my degree, as with many other things, life gets in the way. When I heard the speaker of April’s meeting though it was impossible to not jump at the chance to go….

Figure 1. Mount Etna with the city of Catania in the foreground

On my trip to Masaya back in February I had the privilege of working with John Murray, Visiting Research Fellow at the Open University. A geophysicist, he has worked predominantly on Mount Etna for over forty years. In that time monitoring techniques have moved on greatly, as has much else with the development of technology. This however does not mean proven techniques are not equally, and in some cases, more effective than the new. John specialises in leveling, dry tilt and more recently GPS monitoring of Etna which gives us high precision ground deformation data. For years John secured funding from NERC and many other sources to map the volcanoes deformation. In later years research has become self funded such is his drive to discover the inner workings of the Mediterranean giant.

Figure 2. A map showing the volcanoes of Italy. Etna is the only one laying of the island of Sicily.

Figure 3. John levelling on Masaya.

The other night John addressed the London branch of the Open University Geological Society (LOUGS), to tell them about his work and what he believes 45 years worth of data suggests.

Etna began to erupt roughly 300,000 years at the Val Calanna centre south-west of current activity. Subsequent activity moved on to theTrifoglietto 1 and the Trifoglietto 2 centres before its current position about 170,000 years ago which is sometimes refered to as Mongibello as depicted in figure 4.

Figure 4. Proposed migration Etna based on previous volcanic centers

The Valle Del Bovo is a prominent feature on Etna. The U-shaped depression many believe depict structural failures of the flank along the line of migration of volcanic centres. What John has suggested based on his high precision mapping is that it is not the magma source that is moving but the topography which is slipping seaward.

Also as ground deformation does not following Mogi models (a mathematical model which links changes within a magma chamber to topographical changes), it is being suggested that Etna does not have an appreciable magma chamber, rather taking its material straight from the mantle like a hot spot. This idea is chemically supported by the fact the main igneous rock produced by Etna is Hawaiite; which is compositionally similar to mantle rock.

John is yet to publish his findings in full so I won’t give away any more. It’s safe to say though it is sure to change our views of Etna’s dynamics. John’s passion in his quest to uncover Etna’s secrets is truly inspirational, especially to an aspiring volcanologist like myself. I can’t wait to work on her flanks with him next August.

Figure 5. Eruption February 23rd 2013.

Figure 1; http://en.wikipedia.org/wiki/Mount_Etna

Figure 2; http://www.understandingitaly.com/profile-content/volcanoes.html

Figure 3; Authors own.

Figure 4; http://astrolabio.amicidellaterra.it/node/329

Figure 5; http://mountetnamaddison.weebly.com/eruptions.html

Boxing Day Tsunami 2004 – 10 years on

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Very few natural disasters have effected the entire globe quiet like the events of Boxing day 2004. For me, it was one of the first that captured my full attention and left me wanting to understand how in a matter of minutes thousands of people can just be wiped of the face of the Earth.

The Setting.

The Indian Ocean lays on the western side of the Pacific Ring of fire where the Indio-Austrailian plate is subducting beneath the Eurasian plate along the Sunda trench. Tectonic activity such as earthquakes and volcanic eruption are everyday occurrence in the area. As plates move in relation to each other they can become ‘locked’, unable to move past each other. Over time stress can build up within the locked plate untill the stress can no longer be contained and snaps like a rubber band causing a massive release of energy in the form of an earthquake. This is known as a stick slip fault and is usually the cause of the most powerful earthquakes.

On December 26th 2004 this occurred in spectacular fashion along the Sunda trench. A magnitude 9.2 earthquake rocked the Indian Ocean at 7.58 am. Over an astounding 1600 km stretch of the trench, uplift was recorded to be on average 6 meters. This massive displacement of such a long length of sea bed thrust the ocean waters upwards as well causing tsunami waves which would travel round the world. Such a powerful earthquake is termed a megathrust and released the energy of over 1.1×1017 joules, which is the equivalent of 26 megatonnes of TNT or 1500 Hiroshima atomic bombs.

Despite its violent geology the area is a travelers paradise with millions flocking to the islands  year round. Its equatorial location means year round sun and therefore in especial popular as a Christmas destination. On Boxing day 2004 the beaches were filled you tourist from around the world blissfully unaware of the danger that loomed off the coast.

The Waves.

The first inclination that something was very wrong along the white sandy beaches was a process called draw back. As the earthquake thrusts water up directly above the epicenter water is pulled in from the local area to balance the displacement. From the local shorelines people could see the sea withdrawn quiet rapidly like low tide happening in very fast motion.

At the starting location the tsunami wave looks no more then a small bump on the surface of the ocean and travels at speeds of 500 – 1000 kilometers per hour. As is nears land and the sea floor rises up to the coastline as does the wave rearing up on its self; in this case in excess of 30 ft in places.

The Aftermath.

Over 275,000 people were killed in fourteen countries across two continents, with the last two direct fatalities being swept out to sea in South Africa, more than twelve hours after the earthquake. Scores more died in the coming weeks as decaying bodies and pollution made the spread of disease. Nearly 150,000 homes and buildings were destroyed by the waves.

Identifying bodies was near impossible new mortuaries had to be quickly constructed to handle the masses. In other cases some bodies took months to be washed up on shore and in others they were simply lost at sea.

Public response to the tragedy was unprecedented with over $14 billion US dollars raised by the public world wide, with about the same given by varying governments. It was by far not the worst or most fatal natural disaster in recent years but it touched the hearts of nations world wide at Christmas so every one flocked to help.

Different governments and agencies tended to stick to certain regions in the relief effort as seen above in a relief map produced by the Red Cross.

Road to recovery.

Now ten years on, the countries involved are well on the road to recovery but still scared by the events that Christmas. This years anniversary has seen coverage of the area rocket, with some stunning imagery showing how far certain areas have come since the devastation in 2004.

Will it happen again???

In short, yes. This was the not first major earthquake in this area now will it be the last. By January 1st 2005 there had already been 84 aftershocks ranging between magnitudes 5 to 7. On March 28th 2005 the biggest aftershock occurred just a few hundred kilometers from the original epicenter. Another tsunami was trigger but luckily waves of barely 10 ft were recorded in the local area, still 1346 people lost their lives.

With the tectonic location of the Indian Ocean and its islands, it is never a matter of ‘if’ but a matter of when such events will occur. What hinder this further is it is one of the most densely populated areas of the world but its equatorial weather and fertile volcanic grounds make it prime location for people to live regardless of risk.

Fogo

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As promised, this is a current catastrophe warrants its own post, especially as most of the world does not see it news worthy.

The islands of Cape Verde have become a popular destination for tourists off the coast of Africa. Their origins are volcanic;  as the African Plate moves across a hot spot. Although few of the volcanoes are believed to  extinct the island of Fogo which is thought to sit directly above mantle is rather active.

On November 23rd Pico de Fogo rumbled life again after laying in quiet almost 20 years. In an eruption true to typical hotspot volcanism, there were no huge blasts or billowing ash clouds sent rocketing in to the stratosphere, what there was was lava, volumes and volumes of basaltic lava. Moving at average speeds of just 10 m/ph basaltic lava is easily outrun and the villages like Portela and Bangueira were able to evacuate meaning little threat to human life. Does this therefore follow that there was no threat at all?

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A month on the flow still advances completely devouring the towns of Cha das Caldeiras and Portela. Homes, schoools, businesses completely gone with former residents left helpless on the sidelines. Buildings in Bangueira are also being destroyed and the lava is heading towards other villages.

View image on Twitter

Yet what makes this situation worse is the lack of world support or even knowledge of the unfolding situation in Fogo. Sorry but to me peoples homes being destroyed, livelihoods lost is a big deal. Sadly Kim Kardashian’s naked backside seems to have more media interest than the poor people of Cape Verde.

I have mentioned on several posts that world ignorance to geological events is unbelievable. But what actually makes such news relevant to world media or aid?

Fellow member of the Open University community has a similar view and wrote as such for Science2o. “Does Ebola on mainland Africa and a typhoon in the Philippines mean that there really is no time for an event such as this in our mainstream news agenda? Or do we care about volcanoes only if there’s a chance of them inconveniencing our air-travel plans?”

I wonder how quickly this may change if people understood Fogo’s past and the danger that lays beneath the lava…..

The eastern flank of Fogo is scared from a collapse caused by an eruption around 40,000 years ago. The mass of rock, debris and volcanic material crashed in to the ocean causing a mega tsunami that make 2011’s Sendai disaster look like ripples in a puddle. On the neighboring island of Santiago, evidence of the catastrophic wave can be found over 100 m above sea level. It would of swept far inland on the west coast of Africa and decimated the coasts of Portugal and Spain.

The flanks of Fogo today are still not considered the most stable although it is thought we should not see another collapse in quiet some time, pending on future eruption styles. But the idea that this small volcano, which is currently seen as insignificant to the media, could threaten people on a global scale says so much about peoples ignorance to the planet we live on.

 

Rothery, D. http://www.science20.com/the_conversation/cape_verde_volcano_the_biggest_natural_disaster_you_arent_reading_about-150923

Finally back, and the Earth has not been as quiet as this blog!

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Work, uni, a 7 year old, Christmas and life in general has made posting near in possible the past month or so. The volcanoes around the world have been just as busy as I, so here’s a quick summery;

Barðarbunga

Yes this blogs most talked about lava field is still growing. A press release from the Icelandic MetOffice states the lava flow now covers in excess of 80 cubic kilometres.

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Seismicity continues throughout the length of the dyke and within the Bardarbunga caldera albeit at a reduced rate then earlier in the eruption. Subsidence in the caldera has reached 56 meters in depth, and roughly 1.7 cubic kilometre. Gas emissions continue with elevated pollution warnings still in place through much of Iceland.

On the 29th December the fissure eruption will have been consistent for 4 months, although activity is not as great as in the earlier stages, the eruption shows no indication that the end is in sight.

Kilauea

The June 27th lava flow is still on the move at roughly 300 yards a day. The flow front currently sits less than half a mile away from Pahoa Marketplace where many of the businesses have had to close due to the on coming threat.

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Sections of the flow have been made available, first for students and journalists, and now public to see the lava up close. Eruptions also continue at Kilauea’s summit and East Rift Zone.

Pico Do Fogo

Follow recent events on the Cape Verde island of Fogo has really triggered an anger inside of me in recent weeks and this eruption will have its own post soon after this one is published. However for a brief over view, Pico do Fogo begain eruption back on November 23rd. Since lava flows have devoured local villages forcing over 1500 to flee their homes. Gas and ash emissions have nearly ceased and lava output is now low, although remaining buildings in the village of Bangaeira are still being engulfed by the flow.

Nevado del Ruiz

This Colombian volcano caused one of the greatest natural disasters of the 1980’s. Seismicity has picked up since December 3rd inducing an increased aviation code to yellow. Ash emissions have been sporadic, with a white plume drifting almost 20 km south on December 15th.

Mayon

During 9-16 December white plumes were occasionally observed rising from Mayon’s crater and drifted WNW and WSW, sometimes downslope. Three volcanic earthquakes were recorded on 9 December and one was recorded on 11 December. Alert Level remained at 3 causing PHIVOLCS to remind residents of the 6-km-radius Permanent Danger Zone (PDZ) around the volcano and the 7-km Extended Danger Zone (EDZ) on the SE flank due to recent rockfalls and threat of eruption.

Suwanosejima 

The Tokyo VAAC reported that on 14 December an explosion at Suwanosejima produced a plume that rose to an altitude of 1.8 km (6,000 ft) and drifted SE.

Sinabung

Eruptions at Sinabung have continued and pyroclastic flows and emissions seem to have increased in intensity mid December. Ash plumes have risen in excess of 20,000 ft up to December 16th.

Shishaldin

Poor weather conditions have meant little visual conformation of the Aleutian Island volcano, however due to increased seismicity it is believed that low level lava flows continue from previous weeks. The aviation code remains at orange.

This is just a small sample of the list of volcanic activity in recent weeks, for further updates visit the Smithsonian Global Volcanism Program;

http://www.volcano.si.edu/reports_weekly.cfm

The Science Behind the Unexpected Blast at Mount Ontake

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Saturdays eruption was completly unexpected which is what made it so fatal. So far 47 bodies have been accounted for and at least 16 hikers are still missing. Autopsies on those brought down from the summit have concluded most died from crushed skulls or ribs from the super heated rocks that were catapulted by the blast, other suffered internal burns from inhaling the ash. This has been coined as Japans worst volcanic disaster in living memory but why so in a country so prepared for such disasters.

1. This is the last photo  Izumi Noguchi ever took. His camera was found near his body, his wife released the last pictures he took in his memory.

1. This is the last photo Izumi Noguchi ever took. His camera was found near his body, his wife released the last pictures he took in his memory.

Mount Ontake is one of 47 Japanese volcanoes under constant monitoring. Seismicity, ground deformation and gas emissions are just some of the ways volcanologists can see if magma is migrating towards the surface so why was the 27th such a surprise? The answer is actually quiet simple; it was not a magmatic eruption.

Last weeks eruption was not caused by magma breaking through to the surface as most peoples ideas of volcanoes would expect. Instead it is what is know as a phreatic eruption/explosion. When water, whether it be on the surface or ground water, meets the super heated rock of a geothermal system it instantly turns to steam. It operates on a similar principle as geysers such as those in Iceland or the famed Old Faithful in the Yellowstone system.  Steam does not react well to be confined in the high pressure environments underground and will find any way out it can including smashing rock to smithereens.

1. Basic diagram showing a phreatic eruption/explosion

2. Basic diagram showing a phreatic eruption/explosion

Warning signs for such an eruption are minimal. There was some increased seismicity at Mount Ontake in the week leading up to the 27th but not enough to be classed more than “normal background levels”. In some instances the run up to a phreatic eruption may see slight temperature rises in bodies of water near to the system such as crater lakes, but other than this there are no real indicators for when a phreatic eruption will take place which can make them one of the more fatal styles of eruption.

A week on chances of finding any more survivors is slim, but rescue workers are still scaling the flanks in the area of the eruption as thoroughly as they can before Typhoon Phanfone takes hold of the region.

Figure 1. http://www.dailymail.co.uk/news/article-2779616/The-thing-saw-Hiker-s-photograph-captures-Japanese-volcano-s-ash-cloud-sweeping-moments-claimed-life.html Accessed

Kilauea Update

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The June 27th lava flow is still advancing putting homes in lower Puna at risk. As of Saturday morning the front of the flow was 1.4 miles up slope from Apa’s road and has advance roughly 100 meters since. The lighter vegetation above the road ignited quickly as the lava advanced causing the first bush fire since the flow began in June. Smoke conditions have been moderate to heavy, with most of the smoke is being dispersed to Puna and Hilo. Work is being carried out on Railroad Avenue and Government Beach Road so they are able to accommodate traffic if the lava crossed highway 130.

1. Map of flow as of 20/09/14

The USGS HVO and the Hawai‘i County Civil Defense have been working closely to monitor the flow and advise local resident accordingly.An estimated 300,000 to 500,000 cubic meters (55,000–92,000 gallons per minute) of lava are being erupted each day how ever the flow rate has been fluctuating over the past week or so, slowing since Sunday.

Further information can be gathered at the Kilauea page of the HVO web site;

http://hvo.wr.usgs.gov/activity/kilaueastatus.php

1. http://www.bigislandvideonews.com/tag/june-27-lava-flow/

Bárðarbunga Update

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It has been a while since I have given an update on the Icelandic giant, but that far from means all has been quiet across the waters, more I have been tied up with other bits.

Holuhraun lava field at night.

Holuhraun lava field at night. 12/09/14

The eruption at  Holuhraun appears to be going strong, with now an estimated 200 million cubic tonnes or more of material being erupted since the start of the fissure on the 31st August. Seismicity is still going strong in the area with most around the fissure swarming at the northern end. There is still a lot of seismicity in and around the Bárðarbunga caldera including around earthquake over magnitude 5 yesterday morning, leading people to believe a major eruption from the main vent is still possible.

2. People are still coming from all over to see observe, often from unsafe distances.

2. People are still coming from all over to see observe, often from unsafe distances.

A volcanic haze has enveloped eastern Iceland, on the 9th a Norwegian radio station even reported that the smell of sulfur could be detected along their coast line roughly 1300 km away from the eruption site. The dangerous levels of SiO2 in the air has lead to warnings being issued and locals urged to stay in doors with windows shut. Saturday night RUV reported ” unprecedented pollution levels” with atmospheric sulfur dioxide reaching a spike at 4000 micrograms/m³ (1526 ppm) around 11.00pm.

Iceland’s Met Office are suggesting one of the following are most likely to occur;

    • Subsidence of the Bárðarbunga caldera stops and the eruption on Holuhraun declines gradually.

    • Large-scale subsidence of the caldera occurs, prolonging or strengthening the eruption on Holuhraun. In this situation, it is likely that the eruptive fissure would lengthen southwards under Dyngjujökull, resulting in a jökulhlaup and an ash-producing eruption. It is also possible that eruptive fissures could develop in another location under the glacier.

    • Large-scale subsidence of the caldera occurs, causing an eruption at the edge of the caldera. Such an eruption would melt large quantities of ice, leading to a major jökulhlaup, accompanied by ashfall.

The last of these is a major cause for concern. Jökulhlaups (translates as glacial run)  is a glacial outburst flood often caused by geothermal activity and are extremely dangerous and damaging to any thing in there path.

Elsewhere in Iceland volcanic activity is also caused a stir as Gunnuhver mud pool of the Reykjanes peninsula has been cornered off as activity stepped up well beyond normal levels with boiling hot clay being thrown meters in to the air.

Figure 1. http://www.telegraph.co.uk/news/picturegalleries/earth/11090113/Icelands-Bardarbunga-volcano-spews-molten-rock-over-the-Holuhraun-lava-field.html?frame=3035222 Accessed 15.09.14

Figure 2. http://imgur.com/gallery/4oqueAj Accessed 15.09.14