Wednesday, July 26, 2017

Katla Volcano Has Strong Quakes {UPDATED}

Katla volcano under the Myrdalsjökull glacier just had a magnitude 4.4 quake with many smaller tremors. This is the strongest quake at Katla in the latest unrest which has seen swarms occurring weekly. Katla is thought to be primed for an eruption at any time. Webcam views of Katla are not clear at this time due to fog, so it's impossible to see what is going on. Since this quake sequence just now occurred, it will take some time for Iceland Meteorological Office to give any statement.


Screenshot from Iceland Meteorological Office showing large quake swarm at Katla.


I will update this post as the sequence continues.

*****UPDATE 7/28/2017 *****

After a 3.0 magnitude quake at Katla, harmonic tremor (read: fluid movement and/or magma) is on the rise. You can track the tremor here: http://hraun.vedur.is/ja/Katla/ 
Tremor is continuing to rise and so far is not showing signs of stopping. This could very well lead to an eruption within hours (or days). Now is a good time to keep your eye on Katla, you can watch the webcam feed of it here (note, you may need to use an older browser such as Internet Explorer to view the cam feed as newer browsers have ceased to support Flash): http://www.livefromiceland.is/webcams/katla/ 



Large Earthquake Swarm In Iceland's Reykjanes Peninsula {UPDATED}

A large and somewhat powerful earthquake swarm is currently underway in Iceland's Reykjanes Peninsula in the area of the Krysuvik volcanic center. According to blogger Jon Frimann and the Icelandic Meteorological Office, this swarm is partly tectonic and magmatic in nature. At the time of this writing there have been 9 earthquakes above magnitude 3.0, with one 4.0 tremor so far in the sequence, and dozens of lower magnitude quakes.

Screenshot from en.vedur.is detailing current quake swarm at Rykjanes Peninsula.


Krysuvik volcano last erupted in 1340 CE, according to the Smithsonian Global Volcanism Program. It is unknown whether or not this could lead to an eruption. Reykjanes volcano however last erupted in 1926 CE, but this was a submarine eruption, not on the main island.

If this does end up as an eruptive event, it could put thousands of Icelanders at risk as the area is close to the towns of Volgar, and Grindavik. Previous eruptions of Krysuvik and Reykjanes have been fissure and flood basalt driven, which would mean that large lava flows and gas release would be the biggest hazards. It is still too early in the sequence to tell if this will end up being just a rumble, or develop into an eruption.


Google Earth screenshot showing satellite view and location of volcanic centers. The swarm is occurring between Reykjanes and Krisuvik volcanic centers. 


At current, the Icelandic Meteorological Office has not raised the alert level for the region, which might suggest that they are not anticipating this to develop into an eruption. This could change at any time based on how long this swarm continues for. Since the Krysuvik volcano has not erupted for around 700 years, it is more probable that this swarm is related to the Reykjanes system.

If anything further develops I will update this post.

*****UPDATE 7/27/2017*****


The vigorous quake swarm continues:
                                                  

Second picture is showing increased harmonic tremor which could indicate magma movement. 





Wednesday, June 21, 2017

Katla and Bardarbunga Rumble In Iceland

Katla volcano, and its neighbor Bardarbunga are putting on quite a seismic show in Iceland as of late. Weekly to monthly quakes above magnitude 3.0 have been occurring at both volcanoes, raising anxiety about if or when both of the giant volcanoes will blow. The 2010 eruption of Eyjafjallajökull still fresh in the memories of Europe, when it paralyzed national airports and cost billions to various economies.

Katla volcano is stealing the show today, with large earthquake sequences pulsing now almost daily (which is rather unusual behavior in recent times). It is probable that this is related to magma movement under the crust, and the depths of these quakes are getting shallower. Katla has long been thought 'overdue' for an eruption, although no volcano is ever truly 'overdue' as they do not have scheduled eruptions.


Screen capture from en.vedur.is - Iceland Met Office showing Katla earthquake activity

Katla is thought to be connected in some way to its neighbor Eyjafjallajökull via a magma sill, but the two magma chambers are considered separate. Historically (according to evidence) Katla typically erupts soon after Eyja. This has not occurred yet, although it is suspected a minor subglacial event took place in the year after Eyja's eruption, which was indicated by harmonic tremor and glacier outburst flooding. If there was an eruption, it did not breach the icecap.

Bardarbunga is also rapidly inflating, and has regular quakes within its caldera, and along the old fissure from the Holhuraun lava field eruption. During Bardarbunga's last eruption, the caldera floor dropped many meters, indicating magma chamber drainage via the fissure to its NNE. Current activity has resulted in weekly quakes within the caldera with one or two quakes over 3.0 per pulse. The depths of the quakes and continued deformation indicate that Bardarbunga is far from done with its currently active cycle. 


Screen capture from en.vedur.is - Iceland Met Office showing Vatnajökull earthquake activity

For now nothing seems imminent, but it is especially prudent to keep up with Katla at this time.

Thursday, December 29, 2016

Quake Swarm Along Nevada California Border

A cluster of large earthquakes occurred 12/28/2016 along the CA-NV border with three main events followed by hundreds of smaller quakes. This occurred just north of the Aurora Crater volcanic field along a fault that trends from the Aurora Crater area to Lake Tahoe to the NW. The quake sequence, according to geologists, was tectonic in nature and not related to any volcanism. The last volcanic activity in the area occurred ~25,000 years BP (although the volcanic features are well-preserved due to the arid climate).

Three large quakes struck within hours of each other, at depths ranging from 12km to around 6km. Two quakes registered magnitude 5.7, and were reportedly felt as far away as San Jose to the WSW. The third registered at 5.5, with many aftershocks.


Location of quake swarm. Screenshot form Google using USGS overlay and my modified Smithsonian GVP database. 

According to the Smithsonian GVP, the Bodie-Aurora field is described as follows:

"Aurora-Bodie volcanic field in west-central Nevada near the California border NNE of Mono Lake contains well-preserved cinder cones and lava flows of late Pleistocene age. The most prominent feature, Aurora Crater, is a 25,000 years before present cinder cone surrounded by lava flows. Mud Spring volcano is another late Pleistocene vent with a well-preserved lava flow. Older volcanics of the field include Pliocene andesitic lava domes and Pliocene cones such as Beauty Peak and Mount Hicks."

It is highly unlikely that volcanism is in any way related to this swarm, but full analysis of the swarm is not yet completed by CalVO. Aftershocks are likely for some time, and there is of course always a slight risk that these events could be foreshocks to a stronger event. 

Thursday, December 22, 2016

Campi Flegrei Could Be Close To An Eruption

A new scientific paper published by Italian and French volcanologists is raising anxiety levels over the possibility of a new volcanic eruption from Italy's version of Yellowstone - Campi Flegrei. The Flegrean Fields have long been known for their simmering hotsprings and fumeroles, and it has been known for decades that the land was rapidly inflating. Ancient ruins that showed signs of previous submarine immersion are a-plenty in Naples, and the landscape betrays a violent past.

Geysers, solfataras (which coincidentally owe their name to the region), mudpots, fumeroles, and gaseous fissures plague the region, and new gas vents have recently opened up as the land expands. Now, as it turns out this could spell absolute disaster for Italy, which has already experienced an unfortunate amount of strong earthquakes. Campi Flegrei is near ready to rupture, according the the study.

Now, take this with a grain of salt here, this report does not mean the eruption will happen tomorrow, if at all. But if current trends continue, it does not look good.

There is of course a vigorous debate as to whether inflation in the region is caused by the injection of mew magma into the supervolcanic magma chamber, but competing theories suggest the deformation is hydrothermal in nature. Neither scenario is particularly great.

If the deformation and inflation of the volcanic system is *only* hydrothermal, this could easily end up being a catastrophic phreatic eruption. This could be just as powerful as any fresh magmatic eruption, though likely brief. However if this is the result of new magmatic injection, as the study (linked at top) suggests, then this is definitely very bad news.

The study indicates that there is a 'point of no return' in regards to gas concentration and temperature, where gases that decompress could be hot enough to overcome the tensile strength of the crustal ceiling of the magma chamber, which would result in rapid decompression - an eruption. The study bleakly suggests that this threshold is RAPIDLY approaching. And if this is true, and the current rate of inflation holds steady, then Campi Flegrei is likely to erupt. How strong, nobody is sure, and when, or how strong cannot be accurately predicted.

A super-eruption of Campi Flegrei would immediately put the city of Naples in dire peril, if not effect outright annihilation. The initial eruption would quite quickly generate a tsunami and ash cloud, with the tsunami wiping out vast areas of coastal Tunisia and Algeria. The ash fallout (depending on wind currents) would likely circumnavigate the globe in days to weeks, ushering in a global winter for many years. Keep in mind, the famed 'year without a summer' was generated by a *mere* VEI7 eruption of Tambora. A VEI 8 is at least a thousand times more powerful.

The last super eruption seen by mankind was the eruption of the Toba supervolcano in Indonesia, some 75,000 years ago (according to ice cores and sediment records). This reduced a robust population of early humans down to about 5,000 individuals according to genetic and geological/archaeological studies. Today's human population has a better shot at survival due to our level of technological development on many fronts, but the poorest areas of the globe would likely suffer devastating losses.


To put this into visual perspective....


Italy as thus increased the threat level of the volcano from "green" to "yellow" warranting urgent study. If in fact this giant is ready to blow, we'll likely need all the information we can get, and as soon as possible.

Wednesday, December 21, 2016

Alaska Volcano Bogoslof Pops

AVO has reported (so far) two POWERFUL eruptions from a remote Aleutian volcano, Bogoslof. Bogoslof Island has had many historical eruptions, but is quite remote. Today, pilot reports came in detailing a brief (about 30 minute) long eruption, which produced a high ash column of about 34,000 feet. A second eruption (which has just occurred) has produced another ash column of 35,000 feet. Not small eruptions for any stratovolcano.


Post from AVO showing Satellite imagery of the eruption of Bogoslof.

Bogoslof is the emergent summit (and remnants of multiple domes and peaks) of a large submarine volcano. It is a bit unique for an Aleutian volcano since it rests about 30 miles North of where you'd expect an Aleutian volcano to sit.


Google Earth image of Bogoslof pre-Dec 2016 eruption.

At this time it is unknown what effect the eruption has had on the islands morphology, as many different types of eruptions have occurred here, each leaving a distinct remnant which is typically swiftly eroded (as many oceanic volcanic islands are).

I will continue to update this post with further developments. 

Friday, November 18, 2016

Bardarbunga Returns

Bardarbunga Volcano has just now initiated a series of larger-than-normal background activity quakes which could indicate a new eruption is not far away. In Bardarbunga's caldera, SW from the Holuhraun eruption of 2014-2015, a quake swarm with the maximum magnitude of 4.0, followed by several smaller quakes, and than several 3.0-3.4 quakes hit within the last hour.

What this means is not certain, but it is a part of a pattern of magma movement, that much is clear. Iceland is undergoing a period of active rifting. This rifting enabled Bardarbunga's lava flow at Holuhuraun by making it easy for up-welling magma to find weaknesses in the crust to penetrate and form a dyke intrusion. This eventually gained enough pressure to burst through the crust and create a massive lava field.

The current activity can be seen below:


Current image from Iceland Met Office showing vigorous quake swarm at Bardarbunga Caldera.

The last time Bardarbunga erupted, it was an effusive, not explosive eruption. It was characterised by a fissure opening in the earth, with lava pouring out at a vigorous rate. This was the largest lava-field creating eruption since the devastating Laki fissure swarm in the 1700's. The eruption lasted for months, and created a vast lava field that reached to the boundaries of the Askja volcanic system, which may could also be getting pressurized by the rifting of Iceland. Seismicity in that area has been at a steady level for quite some time now, and it is anyone's guess when it can erupt. 

If, however, Bardarbunga chooses to erupt from it's caldera, this could pose a very large threat to air traffic, local farms and livestock, and create a fair amount of havoc. Eyjafjallajökull's eruption in 2010 was small compared to some of its neighbors like Hekla, Katla, and Baardarbunga. Even the eruption of Grimsvötn (Grimsnes) in 2011 would be much smaller compared to Bardarbunga. It has a much larger caldera, and has proven to have been able to produce very large, up to VEI 6 (Feb. 1477) eruptions.

The main threats from Bardarbunga are large scale plinian eruptions (from the caldera), coupled with lava interacting with ice (which produces pulverized ash, which is quite fine and carries very well on wind currents), and the sheer scale of the magma we're talking about. It's currently, not a small amount. Plainly, it probably won't be much fun for anyone within its reach. And definitely not for aircraft. 

At current I do not believe an eruption to be imminent, but as with all Icelandic volcanoes, sometimes they don't give much warning, so it is worth keeping an eye on tonight.