The ice-covered Grímsvötn volcano on Iceland produced an unusually large and powerful eruption in 2011, sending ash 20 kilometres into the atmosphere, causing the cancellation of about 900 passenger flights. In comparison, the much smaller 2010 eruption of Eyjafjallajökull led to the cancellation of about 100,000 flights.
Understandably, any mention of another explosive eruption from an Icelandic volcano will raise concerns in the air travel industry, which is currently reeling from the COVID-19 pandemic.
But there are clear signs that the Grímsvötn volcano is getting ready to erupt again. As a result, the authorities have recently raised the threat level for this volcano.
Grímsvötn is a peculiar volcano, as it lies almost wholly beneath ice, and the only permanently visible part is an old ridge on its south side which forms the edge of a large crater (a caldera). And it is along the base of this ridge, under the ice, that most recent eruptions have occurred.
Another peculiarity is that the heat output from the volcano is extraordinarily high (2000-4000 MW), and this melts the overlying ice and produces a hidden subglacial lake of meltwater. This is up to 100 metres (328 feet) deep and has ice up to about 260 metres (850 feet) thick floating on it. Fresh ice is continually flowing into the caldera, where it melts, and so the water level just keeps rising and rising.
This meltwater can escape suddenly, and after travelling southwards beneath the ice for about 45 kilometres it emerges at the ice margin as a flood, which in the past has washed away roads and bridges. Fortunately, the passage of meltwater beneath the ice to its outlet can be tracked, and so roads are closed in good time to avoid travellers getting caught in the flood and killed.
Yet another important peculiarity of Grímsvötn is that it can have a hair-trigger response to pressure. This happens when the meltwater lake drains – removal of the water from across the top of the volcano rapidly reduces the pressure.
This can trigger an eruption – it’s like lifting the lid off a pressure cooker. This has happened many times at Grímsvötn.
Grímsvötn is Iceland’s most frequently erupting volcano, and over the past 800 years some 65 eruptions are known with some certainty. The time gaps between eruptions are variable – and, for example, prior to the larger 2011 eruption there were smaller eruptions in 2004, 1998 and 1983 with gaps of between four and 15 years.
Crucially, and with the next eruption in mind, Grímsvötn appears to have a pattern of infrequent larger eruptions that occur every 150-200 years (for example 2011, 1873, 1619), with smaller and more frequent eruptions occurring roughly once a decade in between.
A high frequency of eruptions at a volcano allows scientists to detect patterns that lead to eruptions (precursors). And if these are repeated each time a volcano erupts then it becomes possible for scientists to be more confident that an eruption is likely to happen in the near future.
It is, however, seldom possible to be precise about the exact day.
Icelandic scientists have been carefully monitoring Grímsvötn since its 2011 eruption, and have seen various signals that suggest the volcano is getting ready to erupt.
For example, the volcano has been inflating as new magma moves into the plumbing system beneath it (think of burying a balloon in the sand and then inflating it). Increasing thermal activity has been melting more ice and there has also been a recent increase in earthquake activity.
So what happens next? Again, based on the pattern observed at past eruptions, an intense swarm of earthquakes lasting a few hours (one to ten hours) will signal that magma is moving towards the surface and that an eruption is imminent. In cases where the hidden subglacial lake drains and triggers the eruption, the earthquakes occur after the lake has drained and just before the eruption.
The smaller Grímsvötn eruptions expend a lot of energy when they interact with water and ice at the surface. That means the resulting ash gets wet and sticky and so falls from the sky relatively quickly.
Ash clouds therefore only travel a few tens of kilometres from the eruption site. This is a good scenario for Icelanders and also for air travel, as it prevents the formation of substantial ash clouds that could drift around and close off airspace.
But will it be a small eruption? If Grímsvötn’s past pattern of occasional large eruptions with more numerous smaller eruptions occurring in between continues into the future, then the next eruption should be a small one (given there was a large one in 2011). And the word “should” is important here – Iceland’s volcanoes are complex natural systems and patterns are not always followed faithfully.The Conversation
Courtesy of sciencealert.com
‘Throat of fire’ Tungurahua volcano signalling imminent, devastating COLLAPSE in Ecuador #Tungurahua #Volcano #magma #Ecuador
Scientists are warning that the Tungurahua volcano in Ecuador is showing early signs of impending catastrophic collapse, after satellite data showed substantial internal damage from ongoing magma activity.
Tungurahua, has been persistently active since 1999 so wear and tear was inevitable, especially given that the ‘Throat of fire,’ or ‘Black giant’ as the Quechua indigenous people named it, has already collapsed twice before thousands of years ago.
“Using satellite data we have observed very rapid deformation of Tungurahua’s west flank, which our research suggests is caused by imbalances between magma being supplied and magma being erupted,” says geophysical volcanologist James Hickey from the University of Exeter in the UK, whose worrying research was recently published.
Tungurahua previously collapsed at the end of the Late Pleistocene, after which it then rebuilt itself for thousands of years, before collapsing again about 3,000 years ago.
Such collapses can trigger massive landslides and pyroclastic flows, which can travel for tens of kilometers. For example, the collapse 3,000 years ago is thought to have laid waste to an area of roughly 80km sq (11,000 football fields).
Meanwhile, an eruption in 1999 forced the evacuation of some 25,000 people, so the impact on human life in the area should the volcano collapse again would be truly staggering.
The team admits, however, that magma supply is just one of many risk factors which should be closely monitored to mitigate risk and protect life in the area.
“Magma supply is one of a number of factors that can cause or contribute to volcanic flank instability, so while there is a risk of possible flank collapse, the uncertainty of these natural systems also means it could remain stable,” Hickey says.
Courtesy of rt.com
Taal volcano update: Eruption alert as 116 earthquakes hit Philippines volcano overnight #earthquake TaalVolcano #philippines
The Philippines volcano is showing signs of volcanic activity (Image: GETTY/UNOCHA)
The volcano alert level for Taal is 3, meaning geologists are braced for an eruption in a matter of weeks. According to the Philippine Institute of Volcanology and Seismology (PHIVOLCS), Alert level 3 represents a high level of volcanic unrest.
The alert is marked by sustained seismic activity, plumes of smoke belching from Taal as well as toxic gas emissions and the movement of magma underground.
On Friday, PHIVOLCS warned of 116 tremors were detected around Taal volcano in the 24 hours since midnight GMT (8am local time).
The Taal Volcano Network recorded, in addition, two low-frequency earthquakes, which could be a sign of molten rock entering the volcano.
PHIVOLCS warned: “These earthquakes signify magmatic activity beneath the Taal edifice that could lead to eruptive activity at the Main Crater.”
The agency warned the residents of Luzon Island to stay clear of the volcano in a 4.3-mile-wide radius.
Access to the danger zone is restricted in parts of Agoncillo, Laurel and Batangas.
According to the UN Office for the Coordination of Humanitarian Affairs, about 486,000 people have been affected by the erupting volcano since January 12.
On Friday, the fiery mountain sitting in the middle of Taal Lake was coughing up plumes of dirty steam and smoke.
The volcanic plumes were seen reaching heights between 1,640ft and 2,296ft, drifting in a southwest direction.
At the same time, PHIVOLCS said emissions of toxic sulphur dioxide (SO2) have dropped below instrumental detection.
Although eruptive activity has ceased since two blasts tore through Taal on January 12 and January 13 respectively, the volcano is still at risk of erupting.
Since January 12, Philippine Seismic Network (PSN) has recorded a total of 763 volcanic earthquakes around Taal.
The seismic activity was marked by fissures splitting the ground open on the southern parts of Luzon Island.
At least 177 of the quakes peaked at magnitudes between 1.2 and magnitude 4.2.
Between January 29 and January 31, the PSN recorded seven quakes between magnitude 1.7 and magnitude 2.5.
PHIVOLCS warned on Friday of more earthquakes, steam-driven eruptions, ashfall and lethal gases venting from the volcano.
The agency said: “DOST-PHIVOLCS recommends that entry into the Taal Volcano Island as well as into areas over Taal Lake and communities west of the island within a 7km radius from the Main Crater must be strictly prohibited.
“Local government units are advised to assess areas outside the 7km radius for damages and road accessibilities and to strengthen preparedness, contingency and communication measures in case of renewed unrest.
“People are also advised to observe precautions due to ground displacement across fissures, frequent ashfall and minor earthquakes.”
Riverside communities are at risk of lahars – fast-moving streams of mud, debris and volcanic ash mixed with water, particularly after heavy rainfall.
PHIVOLCS said: “Civil aviation authorities must advise pilots to avoid flying close to the volcano as airborne ash and ballistic fragments from sudden explosions and wind-remobilized ash may pose hazards to aircrafts.
“DOST-PHIVOLCS is closely monitoring Taal Volcano’s activity and any new significant development will be immediately communicated to all stakeholders.”
Courtesy of express.co.uk
Yellow Alert issued due to unusual rapid inflation beneath Mt. Thorbjorn on Reykjanes peninsula, Iceland #YellowAlert #MountThorbjorn #reykjanes #iceland
The map shows recent earthquake activity in the area. Mt. Thorbjorn is situated just above the black triangle which indicates one of IMO’s seismographs.
Inflation has been detected in the last few days. An earthquake swarm has been ongoing during the same period. A state of uncertainty has been declared. The aviation color code has been raised to yellow for Reykjanes.
An inflation has been detected since January 21st and is centred just west of Mt. Thorbjorn on Reykjanes peninsula. The inflation is unusually rapid, around 3-4 mm per day and has accumulated to 2 cm to date. It has been detected both on continuous GPS stations and in InSAR images. The inflation is most likely a sign of magma accumulation at a depth of just a few km. If magma accumulation is causing the inflation, the accumulation is very small, with the first volume estimate is around 1 million cubic meters (0,001 km3). This is the conclusion of a meeting held with the Scientific council of the Civil Protection at the IMO this morning.
Accurate measurements of crustal deformation on Reykjanes peninsula span approx. three decades. During this period no comparable signal has been measured. This is unusual for this period. An earthquake swarm has been ongoing, since January 21st, alongside the deformation signal just east of the inflation centre (northeast of Grindavík). The largest earthquakes occurred on January 22nd and were of M3,7 and 3,6. They were felt widely on the Reykjanes peninsula and all the way to Borgarnes region. The earthquake swarm is currently in decline. Swarms like this are common and not unusual by itself in the area. The fact that an inflation is occurring alongside the earthquake swarm is a cause for concern and closer monitoring.
The inflation is centred within an active volcanic zone
The inflation is occurring on plate boundaries and within the volcanic system of Svartsengi which is either considered a separate system or part of the Reykjanes volcanic system. The last known eruption was during Reykjanes fires, which occurred between 1210-1240 AD. Within that period a several eruptions occurred within that system, thereof there were three eruptions in Svartsengi system. The eruptions were effusive (non-explosive) fissure eruptions erupting on 1-10 km long fissures. No explosive eruptions are known from this system. The largest eruption in the swarm, from 13th century, formed Arnarseturshraun lava (estimated 0,3 km3 and 20 km2). Historically, the duration of these eruptions spans from a few days up to several weeks. Seismic activity is very common in this area and is linked to the plate boundaries, geothermal activity and possible magma intrusions. The largest earthquakes measured in this area are about M5.5.
Courtesy of en.vedur.is
A loud explosion was heard by residents at 10:08 PM, with cracks appearing across roads, & homes at 10:20 PM across Pancho Trace.
11:30 PM Update: Though there has been no confirmed eruption at the Piparo Mud Volcano, there are cracks on the roadway, one home has been damaged due to property cracks, a landslip, and a high sulphur smell according to MP Barry Padarath. He also added, there are no ongoing evacuations but residents are on standby.
Courtesy of Trinidad and Tobago Weather Center
Sernageomin has raised the alert level to Orange for the first time since 2015 due to escalating seismic tremor and a more turbulent lava lake (present in some form since late 2014). Although fairly unlikely, it is possible that a repeat of the March 2015 paroxysmal event could soon occur if there is a similar trend in activity. An exclusion zone of 2km is in force.
Courtesy of volcanodiscovery.com
Earthquakes under Manua Loa during the past week (image: HVO / USGS)
The alert level for the volcano has been raised to yellow two days ago. This doesn’t mean that an eruption is expected to occur in a near future, but acknowledges that the volcano is currently preparing itself for its next eruption, which will come, sooner or later, but currently without possibility to indicate a specific time frame.
The Hawaiian Volcano Observatory (HVO) reported that “for the past several months, earthquake and ground deformation rates at Mauna Loa Volcano have exceeded long term background levels. An eruption is not imminent and current rates are not cause for alarm. However, they do indicate changes in the shallow magma storage system at Mauna Loa.”
Courtesy of volcanodiscovery.com
A volcano in the far eastern end of Russia that was thought to be extinct may now have awakened — and its eruption could be as severe as the one that destroyed the ancient Roman settlement of Pompeii, according to scientists.
In the fall of 2017, seismic activity was discovered underneath the Bolshaya Udina volcano, which was thought to be inactive for decades.
Since scientists began monitoring the area in 1961, only a single weak activity has been detected, according to the Russian Academy of Sciences (RAS).
After the initial activity was discovered, a detailed investigation was launched, which included four temporary seismic stations being placed near the volcano.
Over a two-month period from May to July 2018, 559 localized events were detected in the area of the volcanoes, according to a study that reported the investigation’s findings.
The continued activity led the study to conclude that the volcano may have to be reclassified as “active” given the possible presence of “magma intrusions with a high content of melts and fluids.”
In addition to those events, a 4.3-magnitude earthquake occurred under Udina in February — the strongest to be recorded in that area, according to RAS.
Long-dormant volcanoes pose great risks, according to Ivan Koulakov, the lead scientist investigating the volcano.
“When a volcano is silent for a long time, its first explosion can be catastrophic … Recall Pompeii,” Koulakov told RAS, referencing the ancient Roman settlement Pompeii that was totally destroyed by the eruption of Mount Vesuvius, which was dormant for thousands of years before.
Koulakov also explained that the eruption can have far-flung effects.
“A large amount of ash is thrown into the air, it is carried far away, and not only the surrounding settlements but also large territories all over the planet can suffer,” he said.
This ash can affect air travel and climate, according to CNN.
He pegged the chances of an eruption at 50 per cent.
“At any moment, an eruption can occur,” Koulakov told CNN.
Courtesy of globalnews.ca