Category Archives: Europe

The Decade Volcanoes

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As I reblogged my last post, a revision of the Decade volcano list by the authors of VolcanoCafe, I thought before I bring you the new list I should really explain what the original one actually was!

As mentioned in one of my earliest articles, the list was complied in 1990 by the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) a nongovernmental society. The aim was to select the worlds most hazardous volcanoes and put measures in place to keep a closer eye on them and raise awareness across the globe on the threats they pose, for a decade (1991-2000 The UN’s International Decade of Natural Disaster Reduction). Based on varied criteria from historic eruptions to local populations, the following made the cut;

Figure 1. USGS map of the decade volcanoes.

15 Years on the list is still going all though monitoring in some areas may have slackened slightly. It has seen some success such as the diversion of a lava flow on Etna back in 1992 and has helped form a better understanding of phreatic eruptions on Taal. It has sadly also come at great loss on several occasions as well. Despite increased monitoring of Unzen in 1991 pyroclastic flows killed 43 including volcanologists Katia and Maurice Krafft and Harry Glicken.  And even closer to the project, in 1993 the Decade Volcano conference took place in Pasto, Columbia an expedition from the conference to the Galeras crater occurred on February 14th when the volcano suddenly erupted. 3 tourists and 6 volcanologists including Professor Geoff Brown, Head of Department of Earth Science at the Open University, all lost their lives.

Many volcanologist are sceptics and/or critics of the program, hence the call for a revamp. Personally I feel any thing which promotes volcanic awareness is great all though there are some which need much more than others. Volcanoes are ever evolving and unlike most geological features can change in minutes rather than millennia and therefore prehaps a decade is too long for reviews of such a program. I know which have made my list, it will be interesting to see what makes the cut for the guys at VolcanoCafe!

Figure 1. http://listas.20minutos.es/lista/volcanes-de-la-decada-decade-volcanoes-301649/

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Today in Geological History – May 8th 1902; Mount Pelee

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The 1902 eruption of Mount Pelée in Martinique is always been one which fascinates me. On one hand, it is a perfect example of a volcanoes power to decimate entire communities in an instant and on the other it shows humanities ignorance to heed warnings given by the Earth of impending doom. Modern day Martinique is a paradise island in the Lesser Antilles archipelago, popular with holiday makers but unspoiled by the usual tourist tack. Today Fort-de-France is the capital and home to just over 90,000 people. Back in 1902 this title was given to city of Saint-Pierre, further north than Fort-de-France, and sat at the foot of Mount Pelée.

Figure 1. Modern day Mt Pele

Although the entire island arc is of volcanic origins, owing to the North American plate subducting under the Caribbean plate, it has had very few volcanic events in recent history. On Martinique, Mount Pelée is the most striking volcanic feature towering 4583 ft on the north-west coast. Eruptive phases have been split in to three phases; initial, intermediate and modern which began about 5,000 years ago. Activity is now quite sporadic with about 30 confirmed eruptions so far in its present phase. Prior to 1902 Pelée had only seen minor phreatic eruptions 1792 and 1851 although locals were all to conscious of its fiery past. During the summer of 1900, activity seemed to begin around the Etang Sec crater. Fumarolic and seismicity was low was little attention was paid. In the January of 1902 fumarolic activity increased dramatically and by the February high levels of degassing killed hundreds of birds which many locals thought to be just down to disease. Snakes began fleeing the fumes and that spring saw a record number of lethal snake bites killing over 50 people, mainly children. In the April seismicity began to increase dramatically but still residents of Saint-Pierre still did not fear the mountain.

On April 23rd 1902 the actual eruption began. After a relatively minor explosion ash rained down on its southern and western flanks. A further blast on the 25th sent an ash column high in the sky above the island from the Etang Sec crater. The following day the blasts calmed down, although ash fall continued. At the time Martinique was going through as major political shift. White governed since France took control of the island in the 1600’s, there was now a black opposition leader looking to take power and a major election loomed on May 11th. The residents of Saint-Pierre had this heavily on their mind and further ignored warnings that Pelee was giving, no evacuations took place. On April 27th as ash fall lightened a team was sent up the mountain to investigate. They found Etang Sec filled with water which was boil and giving off a steady stream of steam. Two days later Riviere des Peres and Roxelane swelled as the crater over flowed, carrying debris down the flanks and causing chaos on their banks. But there was more to come…

May 2nd the explosions started again. The first at 11.30 pm created a huge eruption column of dense black smoke and blasts continued ever 5-6 hours through the night. As the ash column drifted over Saint-Pierre finally some residents began to flee. Thick ash covered buildings and roads hindering their escape. By May 5th things appeared to have calmed; then on part of the crater wall collapsed sending boiling water and lahars hurtling down the volcano. Several workers were killed and people fled to Saint-Pierre which was the opposite side to the lahars destruction.  The debris and water surging into the sea at the volcanoes base. At 1pm the sea retreated and a tsunami swept inland.  By 4am on Wednesday May 7th activity stepped up again on the volcano ash billowed and volcanic lightning could be seen around the summit . Though out the day people tried to leave Saint-Pierre but even more were trying to find refuge in the city from the area near the volcanoes flanks. People where frightened didn’t know what to do. News had spread that neighbouring island of St Vincent had also experienced an eruption and Saint-Pierre authorities tried to reassure people who this would relieve pressure in Pelée so the eruption would not get any worse.

As the day went on again things appeared to calm by on the morning of May 8th things took a drastic turn for the worst. Little after 7.50 am, telegraph transmitions from Saint-Pierre went dead. Witnesses which were on ships off shore said the side of the volcano completely gave way near the summit in one colossal blast. A dense black mushroom shape eruption column darkened the sky within seconds. At the same time a pyroclastic surge shot out perpendicular to the column and speed down the flanks towards Saint-Pierre at an estimated 670 km per hour. The surge glowed with its intense heat, ash and clastic material burning in excess of 1000 degrees Celsius, nothing in its path was safe. It’s description gave birth to a new term for such eruption, nuee ardente, french for glowing cloud.

Figure 3. Possibly the most iconic image of the aftermath of April 23rd. Figure 4. The prison cell which saved Louis-Auguste    

An area just over 21 square kilometers was completely scorched or set alight including the city. At the time Saint-Pierre’s population was about 28,000, on May 8th it was likely that the figure was higher as people from nearer the volcano had sought refuge there. There where only two confirmed survivors. Louis-Auguste Cyparis who had been thrown in the towns jail the night before for involvement in a street brawl managed to be protected in his dark damp confines, although he did suffer quite extensive burns.  The second, Leon Compere-Leandre lived on the outskirts on the city, every on else in his house hold perished but he managed to flee, despite horrific burns, 6 km to neighbouring Fonds-Saint-Denis.

By midday, with no contact from Saint-Pierre, the acting governor based in Fort-de-France, sent the warship Suchet to investigate. It was hours before it could make land fall and people could enter the once grand city for the heat. When they did they found little remaining but the dead and devastation.

Aid was quickly sent to help with the recovery operation. The United States alone offered $200,000 and sent Naval staff to help. Canada, Germany, France Italy and Japan too offered assistance. But Mount Pelee was not finished.

On May 20th a second eruption just as intense as that of May 8th sent another pyroclastic flow though Saint-Pierre killing 2000 rescue workers and mariners who were bringing supplies to the area. Activity continued at background levels throughout the summer and on August 30th another pyroclastic flow swept through the area killing at least 800.

The events of 1902 opened up many people’s eyes to the power and annihilation caused by eruption, many even believe it was the birth of the science of volcanology. It gave raise to terms such as nuee ardente and Pelean eruption and lead to further investigation in to eruption styles. When Mount Pelee came to life again in 1929 warnings were quickly heeded and evacuations took place. The most deadly eruption of the 21st century at least left a legacy which saves lives today.

Figure 1; http://www.interestingfacts.org/fact/mount-pelee-facts

Figure 2; http://indonesiandisaster.blogspot.co.uk/

Figure 3; http://www.geology.sdsu.edu/how_volcanoes_work/Pelee.html

Figure 4 ; http://www.emergency.co.nz/archive/pelee.html

Nepal Earthquake

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I sat in a bar last Thursday night discussing the rarity of large-scale natural disasters with several of my non-geologically minded friends. They were shocked to hear just how common certain hazards actually were. I explained that media coverage is scarce depending on fatalities or area of the occurrence, but we have actually been lucky not to have seen any particularly deadly events in a while. Sadly I spoke to soon…

Figure 1. Remains of the Bhaktapur temple, once a UNESCO world heritage site

At 11.56 am local time (06.11 UTC) Saturday, Nepal was rocked by its strongest earthquake in decades. The Mg 7.8 quake was intensified by its shallow depth, just 11 km below the surface, meaning waves had less time to dissipate and disperse leaving the region to feel its full force. This morning officials have raised the estimated death toll again to just under 4000 but it could be weeks before we have real figures. The rescue operation has been hindered by hundreds of aftershocks many over a Mg 5 and even several over a Mg 6 making them devastating events in their own right.

The effects where far-reaching with all neighbouring countries feeling the tremor. India has so far reported 67 deaths and China and Bangladesh 20 and 8 respectively. 19 people lost their lives on Mount Everest as the quake induced avalanches across the snowy region. It is the mountains highest fatality since explorers began ascending its flanks in 1953, scores of hikers are still believed to be stranded.

Figure 2. South Base camp was struck by an avalanche soon after the earthquake killing 12

Why has this earthquake been so devastating?
The answer is a combination of two factors;

Firstly the region is extremely tectonically active. The processes that caused this earthquake are the same that have given rise to the highest mountain range on the planet, the Himalayas. The Indian plate is moving north-northwest towards the Eurasia plate at a rate of 40-50 mm per year. The thick continental crust of the Indian plate instead of simply subducting under the Eurasian plate in to the mantle, like oceanic crust would, actually lifts the opposing plate creating the Himalayan mountain range. Large scale earthquake are relatively common along the subducting surface of the Indian plate as it sticks to the overriding plate, there have been 4 in the last century including Saturdays event. The largest was a Mg 8.0 back in 1934 roughly 240 km southwest of the recent quake; over 17,000 lost their lives. The last was back in 1988 claimed nearly 1500.

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Figure 3.

Secondly despite all this knowledge the country and many of its neighbours are grossly unprepared for such events. Nepal is one of Asia’s poorest countries, many of its residents live in extremely poorly constructed buildings and in many cases shacks. Building codes and regulations in place in richer at risk regions, say San Francisco, are simple non-existent in the Himalayan region. The epicenter was just 77 km north-west of the countries densely populated capital Kathmandu, were it’s believed at least 800 have lost their lives. Surrounding villages have seen complete devastation with no building and very few people surviving.

Figure 4. Huge displacement due to the quake.

Only last month at the UN World Conference on Disaster Risk Reduction identified the potential threat in the region but no further measures were put in place. Hopefully when the rebuilding process begins steps will be taken to limit the threat of future earthquakes.

Figure 1; http://www.theguardian.com/world/live/2015/apr/26/nepal-earthquake-death-toll-exceeds-1500-rolling-report

Figure 2; http://unofficialnetworks.com/2014/04/12-confirmed-dead-everest-avalanche

Figure 3;

Figure 4; http://www.cidi.org/disaster-responses/nepal/#.VT5EMpMYGuQ

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

Current Volcanic Activity; New and Updates.

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Sinabung

Just moments after posting this originally images came through of a pyroclastic flow at Sinabung at 14.05 GMT.
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Fogo

Finally I have found a half decent update from the Global Volcanism Program albeit for about a week or two ago. By the 6th January the lava front had stalled in areas near S Ilheu de Losna where as was still advancing at a slow rate in the northern end of the town. Houses are still being overtake by the flow but decreasing temperatures of the lava means we could be nearing an end to the destruction. For the first few days of the month sulfur dioxide emissions were averaging at 1200 to 1300 tonnes a day.

Etna

Etna saw out 2014 with some pretty explosive activity on the 29th December. The new southeast crater had consistent but small emissions and incandescents. Explosions intensified on the 2nd and 3rd sending material 150 meters above the crater rim and an ash plume which traveled southwest.

Activity has been pretty on going since December 28th and shows little sign of slowing. On January 1st and 2nd, strombolian activity was seen at th Voragine crater, which has been inactive for over two years.

HungaTonga-HungaHa’apai

Based on pilot observations an ash plume rose to just over 10,000 ft on January 6th.  This is the first notable activity at the volcano since 2009. The main caldera is submarine.

Soputan

Darwin VAAC reported that a ‘significant’ eruption began at 14.47 local time on January 6th.  A lava flow has travelled 2 km down the WSW flank although no warnings have been issued. An ash plume rose to roughly 27,000 ft how ever nothing can be detected on satellite imagery due to poor weather conditions. The alert remains at 3 on the four point scale.

Bárðarbunga

As of January 5th the lava flow now covers an area just over 83 square kilometers. although the overall intensity of both flow and seismicity is less then a few months ago, the fissure eruption shows no sign that it is coming to an end.

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Tangkubanparahu

On December 31st the alert d 2 and local residents were warned not to go within a 1.5 km radius of the crater. White plumes has been drifting from the Ratu crater since late November, but an increase in seismicity and ground deformation has led to the apparent rise in threat.

Sheveluch

KVERT reported a lot of strong activity at Sheveluch towards the end of December including incandescent avalanches and fumerolic activity. The aviation code was kept at orange as an ash plume travelled both 60 km westwards and over 370 km ENE. Satellite images indicate a thermal anomaly over a new lava dome on the northern flank.

Comparing Past and Present

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Over the last 12 months we have seen some amazing eruptions, felt the Earth shake on numerous occasions, and remembered some historic events. But was the active of 2014, both volcanically and seismically, more than any other year? I have read several spam articles recently, scare mongering that fracking has trebled earthquake numbers, God’s wrath has been shown by volcanic eruptions and even one drunken woman tried to tell me that Japans tectonic misfortune is due to the Pearl Harbor attack!

Lava field at Holuhraun, Iceland September 2nd 2014.

1. Lava field at Holuhraun, Iceland September 2nd 2014.

Now straight away I can assure you that karma or religious intervention has nothing to do with the science behind the mechanics of the planet beneath our feet. Fracking is up for debate and its effects on seismicity although even were proven the effects are still negligible. So has 2014 really been worse than previous?

Seismically

I found quiet a nice table to demonstrate this one courtesy of Wikipedia.

Number of Earthquakes Worldwide for 2004–2014

  Magnitude Ranging

Between

 2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014
8.0–9.9 2 1 2 4 0 1 1 1 2 2 1
7.0–7.9 14 10 9 14 12 16 21 19 15 17 11
6.0–6.9 141 140 142 178 168 144 151 204 129 125 144
5.0–5.9 1515 1693 1712 2074 1768 1896 1963 2271 1412 1402 1577
4.0–4.9 10888 13918 12838 12080 12292 6805 10164 13303 10990 9795 14941
Total 12560 15762 14703 14350 14240 8862 12300 15798 12548 11341 16674

2014 actually had the lowest number of strong, magnitude 7 and above earthquakes then in the past 5 years. On the flip side of this we had many more lower magnitude  4-5.9 giving us the highest total of quakes in the past 10 years by about 900 earthquakes. 2009 actually is the strangest year on this list with a good 4000 less earth quakes of any magnitude than any other year. 2007 also stands out with an exceptional number of stronger earthquakes. It could be theorized that the greater release of stress and strain with in the crust during 2007 gave us a quiet period the following years. All though this is a very short time scale it does show that yearly variation is great.

625 people were killed in earthquakes last year with most of these during August 3rd’s Ludian County earthquake in China. 6 lost their lives in the strongest quake of the year in Iquique, Chile which was mg 8.2. Nicaragua and Papua New Guinea also had one fatality each. This is actually quiet low value with over 1500 loosing their lives the previous year or as high as nearly 300,000 in 2004!

Uplift caused by Mg 8.2 Chile Earthquake.

2. Uplift caused by Mg 8.2 Chile Earthquake.

Volcanically

2014 was a pretty explosive year with Sinabung kicking us off with a bang January 3rd as it has done this year. In February the same volcano killed 11 as people began to cross the exclusion zones to take a closer look after the pyrotechnics the month previous.

Bárðarbunga stole the show over the summer. The sleeping giant started a ‘will it, won’t it’ game months before any real activity started in August. Many feared we would see an Eyjafjallajökull 2010 style explosion that would disrupt air traffic at the height of the summer period. Earthqaukes then began to indicate magma was on the move through a dyke heading north-west from the main vent. New fears struck as experts wondered would we see devastation similar to Laki 1783. August 29th saw the start of a large fissure breaking the surface, although it has not reached the status of Laki, the eruption is still continuing today

3. San Miguel

3. San Miguel

 

The next lot a fatalities happened when Mount Ontake surprised all with a phreatic blast on September 27th. 57 lost their lives as hikers and tourists where making their way to a shrine on the mountains flank.

Fogo was the volcano to cause chaos in the final month of the year forcing thousands from their homes. Media coverage of this even has been so light on this event, I am unable to find precise news to if the eruption is ongoing. At December 23rd lava was still pouring from the Pico vent and destroying all in its path.

Obviously these are but a few of the hundreds of volcanoes rumbling through 2014. Others include; Colinma, Etna, Aire, Asonsan, Manam, Merapi, Popcatepetl, Shishaldin, Cleveland, Sabancaya, Zhupanovsky, Sheveluch, Santa Maria, Mayon, Dukono, Turrialba, Poas, Fuego, Ubinas, Tungurahua, Reventador, Pacaya, Karymsky, Kelut, Stromboli, San Miguel, Pavlof, Chirpoi and even all that does not cover them all!

But is this more than usual?

In terms of lava output, last year is definitely high up there as we saw several huge effusive eruptions(with Bárðarbunga probably producing more material than most others put together!). However in the grand scheme of things there were few other major events.

68 people lost their lives which is relatively high thinking that on average maybe one or two die yearly unless there are major volcanic events, but then when thinking like that 68 is actually extremely low.

If we were to pull out any year for increased volcanic activity, for me it would have to be the events of 1902. In a list compiled by Wikipedia* of the most deadly eruptions, although none of the top 5 occurred in 1902, 4 in the list of 40 that occurred did, meaning 10% of the most fatal eruptions occurred in the one year. Well over 40,000 were killed over these four eruptions.

4. Somber scene after Mount Pelee eruption May 8th 1902.

4. Somber scene after Mount Pelee eruption May 8th 1902.

Just over 30,000 of these deaths were caused by Mount Pelee, Martinque on May 8th. Just hours before, La Soufriere a few islands away on Saint Vincent killed 1680.

There will always be years there is more geologically activity than others. The Earth is like a living breathing organism; it is ever-changing and adapting, this is part of the reason predicting events can be tricky.  People always look to blame or find meaning behind tragedy, it’s a coping mechanism, but rarely leads to scientific truth.

Figure 1. http://mashable.com/2014/09/11/iceland-bardabunga-volcano-eruption-photos/

Table 1. http://en.wikipedia.org/wiki/Earthquakes_in_2014

Figure 2. http://www.sneakymag.com/life/the-sneakington-post-3/

Figure 3.  http://www.telegraph.co.uk/news/10541931/El-Salvador-begins-evacuations-due-to-volcano-eruption.html

* http://en.wikipedia.org/wiki/List_of_volcanic_eruptions_by_death_toll

Figure 4. http://www.explorevolcanoes.com/Martinique-caribbean-volcano.html

Today in Geological History; Messina Earthquake – 28th December

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On December 28th 1908 Italy saw one of its worst natural disasters killing over 80 – 120 thousand people. It is often referred to as Europe’s worst quake.

At 5.20 am earthquake estimated between 7.1 and 7.5 struck the Strait of Messina. It was felt as far north as Naples and throughout Sicily. If the quake lasting nearly minute was not destructive enough, seafloor displacement caused tsunami waves, averaging about 39 ft, crashing in to the local coastlines.

The towns of Messina and Reggio Di Calabria were completely decimated along with major damage in all coastal towns in Sicily and southern Calabria. Relief efforts where hindered by damage to roads and rail lines, slowing helps arrival to the affected areas. Being in the winters months also caused its own aggravations. As the main shock occurred in the early hours survivors fled in just their night clothes. As most buildings had been torn down people where forced to take to caves and grottoes to escape the blistering cold and rain. It is believed many simply froze to death.

It took the area several years to recover, with many relocating around Italy or immigrating to USA.

This was not first major incident in the area nor will it be the last. In 1693, 60,000 people were killed in southern Sicily by a similar earthquake, and in 1783 most of the Tyrrenian coast of Calabria was raised by a massive earthquake that killed 50,000. The saving grace is since 1908 engineering techniques have come on tenfold and the region does implement some building codes making sure they can withstand larger shocks.