Archive for the ‘Volcanos’ Category

Nostradamus had nothing to say about 2016, but a VEI 5+ volcano eruption is very probable

December 31, 2015

Apart from for 1999, which is specifically mentioned in one of Nostradamus’ quatrains, there is nothing he had to say which can be specifically attributed to 2016. Moreover, not only did the King of Terror he foresaw for the seventh month of 1999 not appear, but there was no event at that time which came anywhere near to his prediction.

So the coming of WW III or of the next anti-Christ or a new invasion of Europe from the Asian steppes in 2016, as many of the Nostradamus brigade are now predicting, are not actually with any foundation. And even if they were, Nostradamus interpretations have a remarkably poor record in forecasts (but a very good record for hindcasts).

Quatrain X-72:

The year 1999, seventh month,

From the sky will come a great King of Terror:

To bring back to life the great King of the Mongols,

Before and after Mars to reign by good luck.

Depending upon calendar, the seventh month refers to July or September. During that period NATO was conducting a local air-war in Serbia and the Russians were battling rebels in Chechnya. But there was little else to match a King of Terror or a new King of the Mongols.

But I do see a high probability of a natural catastrophe during 2016.

The last 25 years have been a remarkably quiet time for major volcanic eruptions. But 2016 may well see a major VEI 5+ volcano eruption, which is now very long overdue. The Puyehue-Cordón Caulle eruption of 2012 is sometimes stated to be of strength VEI 5, but it seems more likely it was no more than a VEI 4. The last VEI 5+ eruptions were in 1991 (Mt. Pinatubo and Mt. Hudson) and that is 25 years ago. Through the 20th century, VEI 5+ eruptions occurred on an average every 7 years (max gap 23 years) and every 11 years during the 19th century. So for 2016, there is a high probability of a major volcanic eruption. Of course, the Ring of Fire is where this is most likely to occur. But my hunch is that the next major eruption could be in the Northern hemisphere. In which case the Mediterranean or Iceland come into the picture.

Ring of Fire image from http://volcanoespaster.weebly.com/

Ring of Fire image from volcanoespaster.weebly.com

I note in passing that the earth’s magnetic field continues to weaken and the poles continue to drift. It is not inconceivable that another rapid magnetic reversal event such as the Laschamp event is currently underway. Reversal of the geomagnetic field occur regularly, but slowly, over geologic time periods. The Laschamp event however occurred very rapidly with the magnetic North Pole drifting to the Antarctic and back again over some 500 years.

Phys.org: 41,000 years ago, a complete and rapid reversal of the geomagnetic field occured. ……. What is remarkable is the speed of the reversal: “The field geometry of reversed polarity, with field lines pointing into the opposite direction when compared to today’s configuration, lasted for only about 440 years, and it was associated with a field strength that was only one quarter of today’s field,” explains Norbert Nowaczyk. “The actual polarity changes lasted only 250 years. In terms of geological time scales, that is very fast.” During this period, the field was even weaker, with only 5% of today’s field strength. As a consequence, the Earth nearly completely lost its protection shield against hard cosmic rays, leading to a significantly increased radiation exposure.

Two other events of note occurred simultaneously – though that may just be coincidence. Forty thousand years ago is close to the time when the Neanderthals disappeared as a separate species and continued only as those absorbed within modern humans. It was also the time when the supervolcano (VEI 7+) erupted 39400 years ago in the area of today’s Phlegraean Fields (Campi Flegrei) near Naples. It was the largest volcanic eruption on the Northern hemisphere in the past 100 000 years.

The polarity reversal was a global event. © Dr. habil. Norbert R. Nowaczyk / GFZ

The magnetic poles are already a long way away from the geographic poles. The South magnetic pole in particular is already outside the polar circle.

NOAA: The most recent survey determined that the Pole is moving approximately north-northwest at 55 km per year.

Currently, in 2015 the location of the north magnetic pole is 86.27°N and 159.18°W and the south magnetic pole is 64.26°S and 136.59°E.

Pole reversal is not a catastrophic event in itself. Even with a weak magnetic field, the atmosphere provides good protection against radiation and the effects would probably not be catastrophic. But the indirect effects of changing flow patterns in the earth’s core (which might be the cause of geomagnetic reversal), on tectonics, volcanic activity and climate may be much more profound. My gut tells me that that the releases of energy which accompany major earthquakes and volcanic eruptions can only be explained by the flow patterns in the earth’s core which power the movement of the tectonic plates – and also control the earth’s magnetic field.

If last year the probability of a VEI 5+ eruption was said to be 95% over the next 5 years, then the chances of a major eruption in 2016 are now quite high.

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Mt. Sinabung lava dome now at 3.3 million cubic metres and still growing

June 15, 2015

Mt. Sinabung started erupting on 27th August 2010 after being dormant for 400 years. It has caused evacuations a number of times and has then quietened down only to start again a few weeks later. Lava flows have reached some 5 km from the summit on a number of occasions. 16 people were killed in early 2014. Mt. Sinabung gives the impression of building up for what could be the next VEI5+ volcanic eruption. One visual indicator is the size of the lava dome building up though it cannot be predicted as to how large a lava dome can get before it collapses. Multiple small collapses are much preferable to a single large collapse. But this lava dome has now grown to about 3.3 million cubic metres.

The shape and size of lava domes varies greatly, but they are typically steep-sided and thick. The thickness can range anywhere from a few meters to nearly one kilometer in height. The diameter or length of these domes can range from a few meters to many kilometers. The form that the dome takes is a function of many factors including strength and viscosity of the lava, as well as the slope of the land they are erupted onto.

On June 6th the lava dome at Mt. Sinabung was assessed to have reached 3.1 million cubic metres having grown around 100,000 cubic metres from the day before. Further assessment since then has been masked by cloud and smoke from the simmering and ongoing eruption. Yesterday “Sinabung spewed hot clouds reaching 3,500 meters to the south and 2,500 meters to the southeast.”

Wrath of Sinabung:: Burning lava streams from the peak of Mount Sinabung in Karo, North Sumatra, Thursday night. The volcano has been spewing lava 100 times a day since the alert was raised to the highest level on June 2, monitors say. (Antara/Zabur Karuru)

Burning lava streams from the peak of Mount Sinabung in Karo, North Sumatra, Thursday night. The volcano has been spewing lava 100 times a day since the alert was raised to the highest level on June 2nd. (Antara/Zabur Karuru) – Jakarta Post

Jakarta Post:

“In today’s eruption, Sinabung’s hot clouds simultaneously moved to the south and southeast. The hot cloud releases to the south reached 3,500 meters, or farther than the ones in the southeast, which reached 2,500 meters. This is because the lava dome is in the southern side of Mt. Sinabung,” Deri told The Jakarta Post on Sunday.

He said Mt. Sinabung still had a huge potential to erupt as the volume of its lava dome was still quite large.

“From the latest data, the volume of Mt. Sinabung’s lava dome has reached 3.3 million cubic meters. Eruptions previously occurred have not yet fully abolished its lava dome; thus, there is still a potential for massive eruptions,” said Deri.

Pyroclastic flows are caused by collapse of parts of the lava dome. On 14th June around ten flows were observed descending to the south-east and through the east-North-east channel.

Probability of a VEI 5+ volcanic eruption within 5 years is over 95%

April 16, 2015

It has been 24 years since the last VEI 5+ (Mount Pinatubo, 1991, VEI 6) occurred and the probability that a VEI 5+ volcanic eruption will occur within the next 5 years is now over 95%. There are around 10 – 14 VEI 5+ eruptions every hundred years and for the the last 300 years the time between eruptions has been as short as 1 year and as long as 23 years. The current gap could be the longest recorded in three centuries. There are, on average, 2 eruptions of intensity 6 every hundred years and so the probability that an eruption of VEI 6 could occur within 5 years is about 50% (current gap 24 years, average gap 50 years). That a supervolcanic eruption of VEI 7 or greater could occur within the next 5 years is less than 1%.

The next VEI 5+ volcanic eruption is overdue During the 19th century VEI eruptions of 5 or greater occurred every 11 years on average with the Krakatoa eruption being the greatest at VEI 6 in 1883. Through the 20th century, an eruption of intensity 5 or greater came at intervals varying from 1 year upto 23 years with an average interval of just under 7 years. The Novarupta (1912) and Mount Pinatubo (1991) eruptions were the two classified at VEI6. 

  • 1902 Santa Maria
  • 1907 Kudach
  • 1912 Novarupta
  • 1913 Colima
  • 1918 Katla
  • 1932 Cerro Azul
  • 1933 Kharimkotan
  • 1956 Bezymianny
  • 1963 Mount Agung
  • 1980 Mount St. Helens
  • 1982 El Chichón
  • 1991 Mount Pinatubo
  • 1991 Mount Hudson
vei eruption balls image geology.com

vei eruption balls image geology.com

So far in this century the 2010 Eyjafjallajökull eruption in Iceland “only” reached a VEI intensity of 4. The Puyehue-Cordón Caulle eruption in 2011 was judged – by some – to be of intensity 5 was really just a VEI 4. The 2012 Mt. Etna eruption was rated a 3+.

Classification of eruptions esf.org

Classification of eruptions esf.org

The impact of the next eruption has to be assessed in a short and a long-term perspective. Immediate loss of life and property is primarily a function of population in the area of the eruption and the time available for evacuation. Populations are higher now than ever in the past but warnings come earlier and possibilities for evacuation are better than ever before.  The population directly at risk from volcanoes in the year 2000 has been estimated at 500 million or more, The long-term impacts could be much more profound and independent of the location of the eruption. We are already into an ocean- current led global cooling cycle. We could well have another year or two without a summer after the next VEI 5+ eruption. The key will be the extent of the dust cloud, the altitude it reaches and for how long it persists. It will not be a Toba like cataclysm which affected the evolution of humans, but it may well be the impulse which drives the earth into an Ice Age. It could even be the start of a 1000 years of transition back into a Glacial Age since the current Interglacial has been around for some 15,000 years.

Extreme Geohazards: Reducing the Disaster Risk and Increasing Resilience VEI values have been determined for more than 5,000 eruptions in the Holocene…. None of these reached the maximum VEI of 8. Several of the most devastating eruptions during the last 2,000 years had VEI values lower than 6. For example, the VEI 5 eruption of Vesuvius in 79 AD destroyed Pompeii and Herculaneum. Since 1500, more than 20 eruptions of VEI 5 or more occurred, with only the Tambora eruption in 1815 reaching VEI 7. It is worth noting that the extremely disruptive eruption of Eyjafjallajökull only reached an estimated VEI of between 3 and 4. …… The size and magnitude of …. the eruption, is only loosely related to the resulting damage. For example, mudflows triggered by the VEI 3 eruption of Nevado del Ruiz (Colombia) in 1985 caused one of the worst volcanic disaster in the 20th century. …… of the nine greatest volcanic disasters in terms of casualties since 1500, only three (Tambora, Krakatau and Laki) qualify as ‘very large’ eruptions with a VEI of greater than 5. ….. during the past 36 Ma, 42 VEI 8 eruptions have been identified. The authors indicate that these eruptions are not evenly distributed in time but seem to cluster in two pulses over the past 36 Ma. Periods with as many as 22 events/Ma and down to 1.4 event/Ma have been identified. More recent examples are the eruptions of Taupo (around 24,000 BC), Toba (around 74,000 BC), and Yellowstone (around 640,000 BC), for which the impacts have been studied in detail. More recent large eruptions with a VEI of 5, 6 or 7 include Thera (≈1630 BC), Vesuvius (79 AD), Laki (1783), Tambora (1815), Krakatau (1883), Novarupta (1912) and Pinatubo (1991). Each of these eruptions (except Novarupta, due to the remoteness of the area) generated immediate loss of life and structures at local distances (through the generation of pyroclastic flows, ash and gas emissions, tsunamis) as well as long-term losses at regional and global distances. These eruptions impacted the climate for long periods by injecting ash in the stratosphere at high altitudes (Tambora’s ash column height reached 43 km) and triggering temperature changes which heavily impacted the harvest and led to famine and epidemics in several areas of the planet: the year 1816, following Tambora’s eruption, is recalled as ‘the year without summer’, and generated abnormal temperatures in China, Europe and North America. 

The hypotheses about man made global warming are neither predictable or measurable and are just fancies. But volcanic eruptions are neither fanciful nor amenable to prediction. They will occur and we have no means of preventing them. Within 5 years it is close to a certainty (> 95%) that a VEI 5+ volcanic eruption will occur. With global mobilisation loss of life can be minimised but the effects of the eruption on climate will just have to be endured.

Bárðarbunga, Iceland: A small fissure eruption has started north of Dynjujökull

August 29, 2014

A flight over the glacier has discovered a row of 10-15 m deep cauldrons south of the Bárðarbunga caldera. They form a long line. The cauldrons have been formed as a result of melting, possibly sub-glacial eruption, uncertain when. There are three circular crevasse formations, about 5 km in total length. The ice thickness in the area is 400-600 m. No signs of flooding have been detected.

Now a small fissure eruption further north has been detected.

The Aviation Colour Code remains at the ‘orange’ level for Bárðarbunga.

Iceland Met Office reports:

A fissure eruption has started north of Dynjujökull.

29th August 2014 02:45 – An eruption north of Dyngjujökull

An eruption started in Holuhraun north of Dyngjujökull at around 00:02. Seismic tremor was observed on all seismic stations and the web camera installed in the area by Mila has showed some nice pictures of the eruption.  It is a small fissure eruption and at 02:40 AM the activity appears to have decreased.

28th August 2014 18:14 – from geoscientist on duty

Since midnight over 1100 earthquakes have been detected by the automatic system. The dyke does not appear to have migrated further north since noon. The main activity is in the dyke and at similar depth as before (8-12km). One earthquake of M5 occurred at 08:13 AM by the northern rim of the Bardarbunga caldera. Two minutes earlier (08:11) another event of M3.9 occurred at a similar location. A few earthquakes were detected near Askja, the biggest one of M2.7.

28th August 2014 12:35 – from of the Scientific Advisory Board

Scientists from the Icelandic Meteorological Office and the Institute of Earth Sciences, together with representatives of the Civil Protection in Iceland, met today to discuss the on-going unrest at the Bárðarbunga volcano.

Conclusions of the Scientific Advisory Board:

  • This morning, there was a flight over the Bárðarbunga area and the surface of the glacier was surveyed. No changes to the ice crevasses southeast of Bárðarbunga, that were seen yesterdayevening, were observed. These crevasses were likely formed due to melting at the ice bottom.
  • The depressions have been located southeast of the Bárðarbunga caldera, in all likelihood within the water divide of the river Jökulsá á Fjöllum. There are three circular crevasse formations, about 5 km in total length. The ice thickness in the area is 400-600 m.
  • The water level in Grímsvötn Lake has been surveyed and has likely risen by about 5-10 m in the last days, which corresponds to an addition of 10-30 million m³ of water in the lake. A slight increase in conductivity in Köldukvísl River was measured this morning, but the cause is yet unknown. No change has been measured in the Hágöngulón lagoon, Jökulsá River and Skjálfandi River. It is assumed, that the water from the cauldron has flowed into the Grímsvötn Lake or the river Jökulsá á Fjöllum.
  • The seismic activity is similar to that of the last days. Around midnight, three earthquakes of magnitude around 4 were recorded and one of magnitude 5 at 08:13 this morning, all located within the Bárðarbunga caldera.
  • Shortly before 08:00 this morning, there was a slight increase in seismic activity in the Askja volcano. Changes in the stress field due to expansion caused by the dyke have an effect on the Askja area.
  • Since yesterday, the length of the dyke under Dyngjujökull has increased by 1-1.5 km to the north, which is considerably less than in the last days. The dyke has now reached the fissure system of the Askja volcano and GPS measurements indicate that the area there is greatly affected.
  • The conclusions from the meeting of the Scientific Advisory Board of the Icelandic Civil Protection will continue to be published at around noon, after the meeting, if necessary.
Iceland earthquake swarm 20140829

Iceland earthquake swarm 20140829

Iceland warns of potential eruption of Bárðarbunga volcano

August 19, 2014

We are due to visit Iceland next month but that may now depend on how this develops.

The Iceland Met Office has upgraded its warning about a potential eruption of Bárðarbunga volcano and said  there were “strong indications of ongoing magma movement”.

The intense seismic activity that started on 16 of August at Bárðarbunga persists. Very strong indications of ongoing magma movement, in connection with dyke intrusion, is corroborated by GPS measurements. There are currently two swarms: one to the E of Bárðarbunga caldera and one at the edge of Dyngjujökull just E of Kistufell. At 2.37 am on the 18th a strong earthquake (M4) was located in the Kistufell swarm.

This is the strongest earthquake measured in the region since 1996. As evidence of magma movement shallower than 10 km implies increased potential of a volcanic eruption, the Bárðarbunga aviation color code has been changed to orange. Presently there are no signs of eruption, but it cannot be excluded that the current activity will result in an explosive subglacial eruption, leading to an outburst flood (jökulhlaup) and ash emission. 

From Volcano Discovery:

The volcano is hidden beneath the northwestern part of the Vatnajökull glacier, and contains a 700-m-deep caldera that is hidden beneath ice and has extensive flank fissures, from where eruptions have taken place: the Veidivötn fissure extends for over 100 km to the SW, almost reaching Torfajökull volcano, while the Trollagigar fissure extends 50 km to the NE touching Askja volcano.

 

vatnajokull glacier and its volcanoes image wired.com

vatnajokull glacier and its volcanos image wired.com

The summary issued on Monday says that though intense earthquake swarm continues at Barðarbunga further movement of magma towards the surface has not been detected.

Summary written 18th August at 20:45

Since the onset of the earthquake swarm at Bárðarbunga on Saturday morning 16th August 03:00am, around 2.600 earthquakes have been detected with the earthquake monitoring network of the Icelandic Meteorological Office (IMO), of these around 950 since midnight (17/18th August). Several of these events were larger than magnitude 3. The swarm initially started in the Bárðarbunga caldera and has been migrating in two clusters towards the north and the east of the volcano.

On Sunday 17th of August, these two clusters were active east and north of Bárðarbunga. The activity in both clusters was migrating northeastwards. While the strongest events were located in the northern cluster, the highest number of events was detected in the eastern cluster. The strongest event since the onset of the swarm was detected on Monday morning 02:37 in the northern cluster. Detailed analysis revealed that its magnitude was 4.5 and it was felt in Akureyri and Lón. By Monday evening, activity has significantly decreased in the northern cluster.

The eastern cluster remains active. Two stronger pulses of activity have occurred between 10:45 and 12:00 as well as 16:50 and 17:30 this morning. Within the first pulse around noon, the cluster was again migrating northeastwards, most events are now located between Bárðarbunga and Kverkfjöll. As reported earlier, GPS ground deformation data has evidenced that the earthquake swarm is caused by magma intrusion.

Throughout the whole sequence until now (18th August at 20:45) the majority of events has been at 5-10km depth. No signs of migration towards the surface or any other signs of imminent or ongoing volcanic activity have been detected so far. IMO is monitoring the area around the clock very closely and will update in case of any changes.

 

Sangeang Api erupts – and an intensity 5+ eruption is well overdue

May 31, 2014

Another volcanic eruption in Indonesia. The odds that the next volcanic eruption of intensity 5 or greater will occur in Indonesia must now be quite significant.

This time the eruption was at Sangeang Api.

VolcanoDiscoveryA major explosive eruption occurred at the remote volcano this morning at around 08:30 UTC. A subplinian eruption column quickly rose to an estimated 50-65,000 ft (15-20 km) altitude and drifted several hundred km to the east and southeast. 
Ash fall was reported in areas up to 30 km downwind from the volcano. 
Luckily, the island itself is largely uninhabited although visted by farmers who cultivate some land. Evacuations were ordered within 1.5 km radius from the volcano. 
Seismic activity preceding the eruption, including a nearby magnitude 4.5 earthquake at 03:05 UTC, was reported felt in the nearby city of Bima (Sumbawa Island) and even on Flores. 
Today’s explosion was the first at Sangeang Api volcano since its eruptions during 1997-99. Increased steaming and a number of earthquakes in recent years might have been precursors to today’s event.

sangeang-api-30may14 photo Bambang Bimawan

sangeang-api-30may14 photo Bambang Bimawan

It has now been 23 years since the eruption of a volcano with an eruption index of 5 or greater. Through the last century, intervals between VEI5+ eruptions were 7 years on average.

ktwopDuring the 19th century there were volcano eruptions having a Volcanic Explosivity Index (VEI) of 5 or greater on average every 11 years. During the 20th century the average was 7 years with the greatest interval between VEI5 eruptions being 23 years. The last VEI5 eruption was in 1991 and now – 22 years on – a VEI5 eruption is overdue.

Mt. Pinatubo and Mt. Hudson (both VEI6) erupted in 1991.

For climate, the net effect of volcanic eruptions – especially those with large dust clouds and aerosol producing gas emissions – is usually of global cooling. We have seen a standstill (and a slight decline) in global temperatures even through this relatively long interval without a VEI5 eruption.  The effects of the 1991 eruptions probably subsided around 1994. The effects of a single eruption on global temperature probably last 2 to 3 years. But any significant, single eruption may well be able to trigger a particular, semi-stable, climate regime. And when the next VEI5+ eruption does occur we are likely to see a more intensive global cooling regime.

Mount Sinabung gets deadly as sightseers return

February 1, 2014

Mount Sinabung which has been erupting since September last year, has caused the first fatalities reported. It erupted again on Saturday ejecting rocks and ash and killing 14. The evacuation zone which extended upto 7km from the mountain has been relaxed to 5km, but the 14 people killed were all from the Suka Meriah village which is within 3km of the volcano. A group of sightseeing schoolchildren is reported to be among those killed. Another 3 people were severely injured when  apparently they had been visiting a family grave and their abandoned homes when the volcano spewed its ash.

On Friday the disaster management agency had allowed people living in villages more than 5km from the mountain to return home. Sixteen villages have been evacuated and residents are not supposed to visit for any reason.

The first eruption occurred at 10:30 a.m. and lasted for eight-and-a-half-minutes, spewing 2-kilometer ash and 4.5-km thick clouds to the south. The second eruption took place at 10:38 a.m. for just over four minutes, followed by another eruption at 11:27 a.m. for 84 seconds.

A villager run as Mount Sinabung erupt at Sigarang-Garang village in Karo district, Indonesia's North Sumatra province, February 1, 2014. REUTERS/Stringer

A villager run as Mount Sinabung erupt at Sigarang-Garang village in Karo district, Indonesia’s North Sumatra province, February 1, 2014.
CREDIT: REUTERS/STRINGER

Sources: Jakarta Post, BBC, Reuters

Related: 5 km radius around Mount Sinabung volcano evacuated as eruptions continue

The next VEI 5+ volcanic eruption is overdue

5 km radius around Mount Sinabung volcano evacuated as eruptions continue

January 13, 2014

Mount Sinabung keeps rumbling on – and more than just rumbling as eruptions with material ejected upto 5,000m and lava flows are observed. Around 25,000 people have been evacuated for 5km surrounding the volcano and the authorities are urging those within a 7km radius to leave.

JakartaGlobe:More than 25,000 people have fled their homes following a series of eruptions and lava flows from Mount Sinabung volcano, an official said Sunday. Mount Sinabung in North Sumatra sent hot rocks and ash up to 5,000 meters (16,000 feet) in the air “several times” on Saturday, National Disaster Mitigation Agency emergency response director Tri Budiarto told AFP.

“So far, 25,516 people have been evacuated. There’s nobody now within a five-kilometer [three-mile] radius of the crater. We are urging those living within seven kilometers southeast of the crater to move too,” he added. Hot lava, which has been spewing from the volcano for the past two weeks, has flowed into a river and filled up valleys with pyroclastic material, he said.

“There were small secondary explosions when lava flows came into contact with the water, but there are no casualties so far. We are urging people not to carry out any activity in the rivers,” he added.

Mount Sinabung is one of 129 active volcanoes in Indonesia that straddle major tectonic fault lines, known as the Pacific Ring of Fire. It had been quiet for around 400 years until it rumbled back to life in 2010, and again in September last year.

During the 19th century there were volcano eruptions having a Volcanic Explosivity Index (VEI) of 5 or greater on average every 11 years. During the 20th century the average was 7 years with the greatest interval between VEI5 eruptions being 23 years. The last VEI5 eruption was in 1991 and now – 22 years on – a VEI5 eruption is overdue.

Mount Sinabung started its rumblings back in September 2013 and it may be that the continuing small eruptions relieve sufficient pressure to prevent a VEI5+ eruption. But the odds that the next VEI5 eruption occurs in or around Indonesia is still quite high – and it could be that Sinabung is just bubbling up to be a major eruption. However the eruptions are being monitored so closely that any such imminent eruption will probably be detected early enough to get most people out of harms way.

Mount Sinabung Indonesia - Google Maps

Mount Sinabung Indonesia – Google Maps

Supervolcanos can erupt sponataneously without an external trigger

January 7, 2014

New research suggests that supervolcanos do not need an external trigger to erupt. Bouyancy effects and the magma volume could be sufficient for spontaneous eruption.

Wim J. Malfait, Rita Seifert, Sylvain Petitgirard, Jean-Philippe Perrillat, Mohamed Mezouar, Tsutomu Ota, Eizo Nakamura, Philippe Lerch, Carmen Sanchez-Valle. Supervolcano eruptions driven by melt buoyancy in large silicic magma chambersNature Geoscience, 2014; DOI:10.1038/ngeo2042

From the Press Release:

Scientists have reproduced the conditions inside the magma chamber of a supervolcano to understand what it takes to trigger its explosion. These rare events represent the biggest natural catastrophes on Earth except for the impact of giant meteorites. Using synchrotron X-rays, the scientists established that supervolcano eruptions may occur spontaneously, driven only by magma pressure without the need for an external trigger. The results are published in Nature Geosciences.

A well-known supervolcano eruption occurred 600,000 years ago in Wyoming in the United States, creating a huge crater called a caldera, in the centre of what today is Yellowstone National Park. When the volcano exploded, it ejected more than 1000 km3 of ash and lava into the atmosphere, 100 times more than Mt Pinatubo in the Philippines did in 1992. Big volcanic eruptions have a major impact on the global climate. The Mt Pinatubo eruption decreased the global temperature by 0.4 degrees C for a few months. The predictions for a super volcano are a fall in temperatures by 10 degrees C for 10 years.

Abstract: Super-eruptions that dwarf all historical volcanic episodes in erupted volume and environmental impact are abundant in the geological record. Such eruptions of silica-rich magmas form large calderas. The mechanisms that trigger these super-eruptions are elusive because the processes occurring in conventional volcanic systems cannot simply be scaled up to the much larger magma chambers beneath supervolcanoes. Over-pressurization of the magma reservoir, caused by magma recharge, is a common trigger for smaller eruptions, but is insufficient to generate eruptions from large supervolcano magma chambers. Magma buoyancy can potentially create sufficient overpressure, but the efficiency of this trigger mechanism has not been tested. Here we use synchrotron measurements of X-ray absorption to determine the density of silica-rich magmas at pressures and temperatures of up to 3.6 GPa and 1,950 K, respectively. We combine our results with existing measurements of silica-rich magma density at ambient pressures to show that magma buoyancy can generate an overpressure on the roof of a large supervolcano magma chamber that exceeds the critical overpressure of 10–40 MPa required to induce dyke propagation, even when the magma is undersaturated in volatiles. We conclude that magma buoyancy alone is a viable mechanism to trigger a super-eruption, although magma recharge and mush rejuvenation, volatile saturation or tectonic stress may have been important during specific eruptions.

Supervolcanos do not occur all that often – perhaps one every 50,000 to 100,000 years. When they do occur they devastate a large geographical area and affect the climate for a decade or so. How much destruction of organic life occurs depends on the geographical area affected and the life that is extant there.

New Zealand’s Taupo Volcano was the most recent and erupted about 26,500 years ago. With a VEI of 8, just over 1,000 kmof ash were ejected. Though modern man had reached Australia by then, the effects of this eruption do not seem to have significantly delayed the march of humans. The Toba eruption 74,000 years ago occurred when the total population of all human species (Modern Humans, Neanderthals, Denisovans …..) was between 1 and 10 million. This eruption is also classified as a VEI of 8 and 2,800 km³ of material was ejected. Life was virtually extinguished from India to South East Asia. The effects were devastating not only in the fall out-zone but also – it seems – in hampering the expansion of modern humans out of AfricarabiaThis eruption may thus have caused one of the critical bottlenecks which has determined the subsequent evolution and expansion of humans. 

Image

Toba Fallout (Smithsonian Institute)

While a supervolcano could erupt at any time, it is much more probable to occur than a major asteroid collision with the earth (one in 100,000 years as opposed to once in tens of millions of years). But the volume of magma involved suggests that some early detection (perhaps 5 -10 years) may be possible. For the pressure to build up sufficiently in such a volume a significant bulging of the earth’s crust is likely and should be detectable. But while science fiction can imagine a battery of nuclear warheads to divert an oncoming asteroid in its trajectory, it is difficult to conceive of any way to prevent a supervolcano from erupting. Geo-engineering on a  scale massive enough to relieve some of the pressure in the magma is just conceivable at the edge of fantasy but even that could not prevent the eruption.

Undersea volcanic activity creating new island chain at Norway’s Loki’s Castle

August 3, 2013

South of Svalbard between Norway and Greenland there is vigorous and active field of hydrothermal vents on the sea floor along the Mid-Atlantic Ridge. The field lies in Norwegian waters and is located at  73°33′N 8°09′Ø, about 300 km west of Bear Island and about 600km east of Jan Mayen Island and at a depth of about 2,350m. It was discovered in 2008 by researchers from the University of Bergen and has been called Loki’s Castle (Lokes slott in Norwegian).

Loki's Castle on the Mid-Atlantic Ridge

Loki’s Castle on the Mid-Atlantic Ridge

In 2008, University of Bergen researchers found metal deposits and unique wildlife in the environment created by the hydrothermal vents.

University of Bergen News

This summer a team led by the director of UiB’s Centre for Geobiology, Professor Rolf Birger Pedersen, discovered five new hydrothermal vents in Loki’s Castle. The vents were discovered at depths ranging from 100 to 2,500 metres. In this area, which is the most geological active part of Norway, a new volcanic seabed is formed at a rate of two centimetres a year.

… Norway is a volcanic country on par with Iceland. The difference being that whereas Iceland’s volcanoes are onshore, Norway’s volcano landscape is in the deep sea. Norway’s volcanoes are lined up underwater in large active earthquake zones, and there are hydrothermal vents churning out hot water – at 320 degrees Celsius – which gives rise to unique ecosystems and metal deposits on the seabed. ….

…. For the past ten years, researchers and students from the centre have explored this volcanic underwater world. Through their summer expeditions to the area, they have discovered new Norwegian nature every year. In this period they have surveyed hundreds of undersea volcanoes and a number of hydrothermal vents. Loki’s Castle (Lokeslottet), Soria Moria and Trollveggen are the names given to the hydrothermal vents discovered by the UiB researchers in 2005 and 2008. ..

 They have found significant metal deposits that are formed around the hydrothermal vents in Loki’s Castle. The material value of these deposits remains unknown, but the mining industry is already showing a growing interest in exploiting these resources on the seabed. Deep-ocean mining could become a reality in the not too distant future. The distinctive wildlife in the deep seas, with the hydrothermal vents as oases of a unique genetic life, means that any industrial activity must be weighed against environmental concerns.

Based on their knowledge, the UiB researchers are thus proposing that deep-marine nature parks should be established as soon as possible. This is of particular importance for Norway, with vast deep-sea areas to manage. This management must be based on scientific knowledge.

Video of the undersea volcanoes.

The Local

“We have discovered five new vent fields in Norwegian national waters between Jan Mayen island and Loki’s Castle,” Rolf Pedersen, the professor leading the research, told The Local.  “The vent fields were discovered during a cruise with RV GO Sars in July this summer. ……. 

Pedersen made his name in 2008 when he discovered the underwater volcanic range Loki’s Castle. The new discovery comprises hundreds more volcanos, some just 20m below the surface. 
 
“We have found volcanoes at such a shallow level and they could break the surface at any time and form a new island group,” Pedersen told VG newspaper.  “We have long known that Iceland has both volcanic activity and hot springs, but we thought that we did not have anything like that in Norway. But we do, it was only under water.” 
 
The scientists have already discovered some 50 new species on the site, which Olsen said could lead to new drugs being developed. 
 
“There are biological species which haven’t been discovered before that live in extremely harsh environments. This brings the potential to discover new molecules that we haven’t been aware of which could be used in the development of drugs.” 
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In Norse mythology Loki was one of the jǫtnar, a mythological race, and a god.

Loki is the son of Fárbauti and Laufey, and the brother of Helblindi and Býleistr. By the jötunn Angrboða, Loki is the father of Hel, the wolf Fenrir, and the world serpent Jörmungandr. By his wife Sigyn, Loki is the father of Narfi and/or Nari. And by the stallion Svaðilfari, Loki is the mother—giving birth in the form of amare—to the eight-legged horse Sleipnir. In addition, Loki is referred to as the father of Váli in the Prose Edda.

Loki’s relation with the gods varies by source. Loki sometimes assists the gods and sometimes causes problems for them. Loki is a shape shifter and in separate incidents he appears in the form of a salmon, mare, seal, a fly, and possibly an elderly woman. Loki’s positive relations with the gods end with his role in engineering the death of the god Baldr. Loki is eventually bound by the gods with the entrails of one of his sons.


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