Friday, November 14, 2014

Curious Quake Swarm in NW Nevada [UPDATED 11/14/14]

Nobody at all is reporting on this, although it's no secret either. There is an oddly shallow and very active quake swarm occurring in NW Nevada, about 65 KM ESE of Lakeview, Oregon (as USGS reports it) and it has been going on now for over a week and a half.

The area the quakes are occurring in does not seem to have any significant human population, and appears to be mostly mountainous desert, overlain by igneous rocks of what I'm guessing are older than pliestocene. There isn't a lot of info on the area, much less any geological information I'm able to find.

In any case it appears to be a long series of very shallow quakes ranging in size from <1.0 to greater than 3.5. The area does appear to be on a spreading rift, and probably has a past history of volcanism, but there are no records to confirm this.

As these quakes have ranged in depth from <2km to near surface, I'd say we are looking at a purely teconic event, and nothing related to volcanism. Again, there are no news articles or blogs I'm able to find. Below is a screenshot.


Google Earth Screenshot of location of quake swarm using USGS overlay.

I'm purely writing about this out of curiosity, and want to keep speculation to a bare minimum. I wonder if any USGS people would like to comment on what they suspect this is? It's happened before!

*****UPDATE 8/21/2014*****
Looks like the media and geologists are finally taking notice of this quake swarm. So far, indications are that it is purely tectonic, but they don't know yet. The area has a history of tectonic activity, however this swarm appears to be unprecedented for the region. Here are the few reports I could find on this:

http://www.oregonlive.com/pacific-northwest-news/index.ssf/2014/08/seismologists_are_tracking_swa.html
http://www.rgj.com/story/news/2014/08/19/earthquake-swarm-northwest-nevada-see-map/14301965/

*****UPDATE 8/29/2014*****

The quake swarm in NW Nevada continues, adding a magnitude 3.8, 3.2, and numerous smaller quakes. All are occurring at depths less than 2km, and some (probably not manually reviewed, and auto-detected quakes) are occurring near or at the surface according to the data feed (which is probably not accurate). So far there is no analysis from USGS aside from what has been briefly mentioned in articles. This 'swarm' is interesting at least to me. There are volcanic basalt cliffs in the area, and it does appear to be part of a rift zone. There is little to no human population in the area, and I am wondering if anyone has visited it to gain some visual observations, or install more instrumentation. At this time, it's being reported that this is purely tectonic, and there are no reports of anything to suggest otherwise, however volcanic activity or dike intrusion can't be ruled out given the composition of the surrounding rocks. Something odd is going on up there.

*****UPDATE 11/6/2014*****
Surprisingly, this swarm is still active. A 4.7 magnitude quake, and a 4.6 are so far the largest quakes of the resurgent swarm. There is no explanation from USGS other than 'this is probably tectonic'. I tend to agree, as the quakes are extremely shallow, in some cases appearing to be so shallow it reads as '0.0 km depth'. However, the 4.7M quake was at a depth of around 5km, which can indicate some sort of volcanic origin. It's still way to early to tell what's going on, and without comprehensive analysis by USGS or a geologist, I still have no new info to really put forth, other than the swarm has been active now for months, which is certainly unusual. I can find no analysis, GPS charts, or otherwise to give any more details, but I will follow up when any info comes out (I am keeping my eye on this). Stay tuned!

*****UPDATE 11/14/2014*****

The quake swarm continues, with USGS releasing a statement saying they are finally going to be out in the area installing new equipment, which should give us a much better picture about whether this even is simply tectonic 'exfoliation' events, rifting, or perhaps even volcanic (which is highly unlikely, but not impossible). The duration of the swarm is still quite interesting, as it has now been occurring for several months now.

Thursday, November 13, 2014

Mauna Loa Priming For Eruption [UPDATED 11/13/2014]

Mauna Loa Priming For Eruption
Hawaii’s largest volcano, Mauna Loa, is priming for eruption according to the Hawaiian Volcano Observatory (HVO). A statement from HVO says the following:

“MAUNA LOA VOLCANO (VNUM #332020)
19°28'30" N 155°36'29" W, Summit Elevation 13681 ft (4170 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Seismicity continued to be slightly elevated; deformation patterns may suggest renewed inflation.

Monitoring data through the month of September 2014:

Seismicity: Seismicity at Mauna Loa remains elevated in several parts of the volcano. In late September, a swarm occurred to the west of Moku`āweoweo Crater. The swarm had a maximum magnitude of 2.4 and several events that were large enough to be located. In total, there were up to 150 separate earthquakes that were part of this swarm, most too small to be recorded on enough stations to be accurately located, however we infer that their location is similar to the formal locations of the larger events. The same area had a swarm in September and October of 2013. Several long period earthquakes were present at depths from 50 km to the shallow edifice, with most LP earthquakes between 9 and 15 km depth. Earthquake rates on the Upper Southwest Rift Zone (Sulfur Cone) remain elevated, though similar to the past couple of months. Seismicity rates in the Moku`āweoweo Crater increased over previous months with approximately 50 very small events in the past month at shallow (<5 km) depths. All earthquakes in the past month have been small relative to earthquake sequences observed before eruptions in 1975 and 1984.

Deformation: On Mauna Loa, GPS data continue to show a broad pattern of displacements suggesting inflation. Preliminary modeling shows the data to be consistent with inflation of one or more magma reservoirs, with the majority of the volume accumulating in a dike-like body beneath the caldera and upper rift zones. Reinflation may have started very slowly in April or May of this year. Displacement rates have been variable, with higher rates in July and August and slowing again in September.”

While this does not mean Mauna Loa is at risk for imminent eruption, it does mean that it is more likely than before. Historically, Mauna Loa is Hawaii’s most active volcano, although it has not had an eruption since its last event in 1984. It had erupted about 33 times since its first documented eruption in 1843. Its eruption in 1984 produced some fast moving lava flows which did cause property damage, and it is likely future eruptions will be similar in style.

At this time, it would be a good idea for islanders to begin seriously preparing for a future eruption. There is no way to tell where an eruption might begin on Mauna Loa, all surrounding areas are at risk. It is interesting that Kilauea still shows no signs of stopping its eruption, as the constant outflow of lava tends to prevent rapid inflation at Mauna Loa, so this could mean Hawaii’s mantle  plume may be getting a bit more active, but that’s just speculation. If it were true, we might expect to see more activity from Loih’i, and possibly Hualai or Mauna Kea (although activity at Mauna Kea is highly unlikely).

*****UPDATE 11/13/2014*****

Mauna Loa continues to inflate. GPS readings show a broad pattern of displacement, and fumerole temperatures are rising at the summit. It is likely the volcano will erupt within the next year or so. The new report from HVO is below:

"MAUNA LOA VOLCANO (VNUM #332020) 

19°28'30" N 155°36'29" W, Summit Elevation 13681 ft (4170 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Seismicity continued to be slightly elevated; deformation patterns may suggest renewed inflation.

Monitoring data through the month of October 2014:

Seismicity: Earthquake rates on the Upper Southwest Rift Zone (Sulfur Cone) remain elevated, though similar to the past couple of months. Seismicity rates in the Mokuʻāweoweo Caldera remains elevated with approximately 40 very small events in the past month at shallow (<5 km) depths. All earthquakes in the past month have been small relative to earthquake sequences observed before eruptions in 1975 and 1984.

Deformation: GPS data continue to show a broad pattern of displacements suggesting inflation. Preliminary modeling shows the data to be consistent with inflation of one or more magma reservoirs, with the majority of the volume accumulating in a dike-like body beneath the caldera and upper rift zones. Reinflation may have started very slowly in April or May of this year. Displacement rates have been variable, with higher rates in July and August, slowing in September and possibly slightly picking up again near the end of October.

Gas: No significant changes in SO2, CO2 were recorded by the Mokuʻāweoweo gas monitor; however, a minor deviation in fumarole temperature was recorded over the past two months. The correlation between fumarole temperature increase, elevated seismic tremor levels, and tilt values reported in September was coincidental. This month, we've continued to record a fairly sharp anomalous 2-3 degree C temperature increase.

Background: Re-inflation of Mauna Loa's shallow magma storage reservoirs started immediately following the most recent eruption in 1984, then turned to deflation for almost a decade. In mid-2002, inflation started again, just after a brief swarm of deep long-period (LP) earthquakes. A more intense swarm of several thousand deep Long Period (LP) earthquakes occurred in late 2004, immediately preceding a dramatic increase in inflation rate. Inflation slowed again in 2006, ceased altogether in late 2009, and resumed slowly in late 2010.

Rising gradually to more than 4 km above sea level, Mauna Loa is the largest active volcano on our planet. Its long submarine flanks descend to the sea floor an additional 5 km, and the sea floor in turn is depressed by Mauna Loa's great mass another 8 km. This makes the volcano's summit about 17 km (56,000 ft) above its base! The enormous volcano covers half of the Island of Hawai`i and by itself amounts to about 85 percent of all the other Hawaiian Islands combined.

Mauna Loa is the largest active volcano on Earth and is among Earth's most active volcanoes, having erupted 33 times since its first well-documented historical eruption in 1843. Its most recent eruption was in 1984. For more information on Mauna Loa, see the USGS Fact sheet available at http://pubs.usgs.gov/fs/2012/3104/fs2012-3104.pdf. 

CONTACT INFORMATION:
askHVO@usgs.gov"

Wednesday, November 12, 2014

Italian Geologists Convicted Of Manslaughter Acquitted

In a trial that shocked the scientific world, several Italian geologists were convicted by the Italian court of 'downplaying the potential for damage of an earthquake in the L'Aquila region' in 2009. This conviction was the first precedent set to actually convict scientists for failing to do something that nobody in the world can do - predict when, where, and how strong an earthquake will be. It all started in 2009 when the L'Aquila Italy quake, a magnitude 6.3 quake, damaged historical buildings, and modern infrastructure. The damage was widespread, and during a time of economic turmoil, this exacerbated public outrage and people demanded 'someone be held responsible'.

Many in the world and media considered their convictions as precedent for forcing scientists to 'predict earthquakes'. They have now been acquitted of manslaughter charges, and released from prison after five years.

The convictions of these scientists prompted a mass-exodus of geological professionals from Italy to other countries. The fact that this ever happened damaged Italy's scientific community, seemingly irreparably. It is unclear whether the scientists acquittal will reverse the damage to the trust the scientific community had with the Italian government.


Tuesday, November 11, 2014

Quake Swarm South Of Lassen Volcanic Center

A nice quake swarm is occurring just South of Lassen Volcanic Center in California, US. The largest quake so far in the series has been a 3.9, and at this time the swarm is ongoing. So far around 35 quakes have occurred in the area over magnitude 1. It is unclear at this time whether the quakes are tectonic or volcanic in nature, however the fact that most are quite shallow could indicate this is merely a tectonic or hydrothermal event. Time will tell.


Quake swarm south of Lassen. Screenshot from Google Earth with USGS realtime quake overlay.

In all probability, as with many California quake swarms, this is related to fluid/hydrothermal movement within the crust, and probably isn't any big deal. The quakes to the East of the swarm seem to be at depths of up to 8km deep, and the ones to the West get progressively shallower. While this could indicate magma dike intrusion, that would be surprising, as some quakes are occurring on the surface, and so far there are no reports of activity in this very popular mountain hiking spot. It is likely, as most swarms in CA, that this will not result in an eruption, but it is still too early to know. 

Lassen last erupted in 1914-1917, California's only stratovolcano eruption in the last century. The eruption started with a phreatic explosion, and ended up building, and subsequently destroying, a summit lava dome which flung large boulders many miles from the summit. The famous 'Hot Rock' monument is a large boulder from this eruption. 

Lassen will likely erupt again in the future, although the current events are unlikely to make this happen. As with most West Coast volcanoes, their eruptions are infrequent, but very powerful. Should an eruption at Lassen occur in modern times, it would be more damaging than its previous eruption as the land around it has been developed.

So far, the news is slow to report, and they have less info than I do on my blog.

*****UPDATE 11/12/2014*****

The quake swarm continues. So far no quakes bigger than the 3.9. Most have been fairly near the 'middle' of the swarm area today, around depths of 4km. There has been no really detailed statement from USGS so far, other than 'swarms in this area are common' and 'this does not appear to be related to volcanic activity'. As I do not know where I could possibly view tremor plots in this area like you can with Alaskan, or Icelandic volcanoes, I can't really offer any more analysis than anyone else outside the USGS. If anything further actually develops, I'll update this post, but my guess is this is just another little swarm in the area, and not a whole lot will happen.

Tuesday, November 4, 2014

Bardarbunga Volcano Largest Eruption In Iceland In Over 200 Years

Bárðarbunga volcano in Iceland is defying expectations and is producing so much lava, it is now the second largest eruption in Iceland's history, after the 1783 eruption of Laki, which erupted for over 8 months. The current fissure eruption, which many volcanologists and bloggers like myself believe to be a precursor the main event, has now produced nearly 100 square kilometers of lava, and the gas being emitted is definitely beginning to cause problems for Icelanders, much like the Laki eruption.

Bárðarbunga volcano is a caldera and fissure system, which can be, and is, a potentially deadly combination.

Since my last blog post on the subject, not a whole lot has changed, except now some predictions such as caldera subsidence, jökullhlaups (glacier outburst floods), and massive amounts of SO2 being emitted are starting to come to fruition.

The main caldera of Bárðarbunga continues to subside at a steady rate of around 40-50cm a day, and it is showing at the caldera rim. A large 'cauldron' where the ice-covered caldera lies is clearly visible now during overflights. Other smaller 'cauldrons' are appearing near the rim as well, as heat from magma getting close to the surface warms the rock. The latest report on the caldera is saying around 2 cubic meters per second of ice is being melted (that's a lot), and they are expecting drainage at any time.

The biggest danger to people right now is twofold. The SO2 gas can and does cause lots of breathing issues, especially for people with asthma, and the elderly. People are advised to stay indoors if they encounter poor air quality, as SO2 can easily damage the alveoli in your lungs, causing permanent damage. The other threat is that of jökullhlaups, glacier flooding, which occurs when a large pocket of water is generated within a glacier, causing the temperature difference to eventually rupture out of the ice wall with near explosive force. This can happen at any time, and has caused massive damage to property and infrastructure from much smaller volcanoes.

The current situation at Bárðarbunga is getting more and more dangerous as the fissure eruption progresses. The worst case scneario right now is if the caldera continues to subside, with ice and rock eventually coming into contact with the magma conduit, which would result in not only flooding, but a very explosive eruption, much larger than that of Eyjafjallajökull, or Grimsvötn (Grimsnes). If I were to estimate the scale of the eruption, it would likely be around a VEI 3-5 event, depending on the internal mechanics.

However at this time, the eruption remains stable. Since the fissure has opened, it has consistently maintained its flow, and seismicity has decreased. This means that currently, as much magma is flowing into the dike intrusion as is being erupted as lava onto the Holhuraun lava field. If the fissure stops erupting and magma flow remains steady, it is anyone's guess as to what could occur. One possibility is that the eruption ceases altogether, which is unlikely. Another is that other fissures will open when the magma finds another route to the surface. Another is that the caldera of Bárðarbunga inflates, and an eruption occurs due to changes in caldera structure which will now have more fractures and avenues for the magma to reach the caldera.

Really, nobody knows for sure where this is going, but one thing is certain, this is a whopper of an eruption for Iceland, and is truly fascinating. FUTUREVOLC, a project which is using Iceland as a laboratory to study volcanic mechanisms is practically thrilled with the data they're able to be collecting, and Iceland itself does see an uptick in tourism. Many are braving the harsh conditions and risk of gas exposure to capture photo and video of the volcano (I'm fine right here watching the webcam), which can be risky. Earlier in the eruption, a billionaire from Europe defied orders by Iceland to stay away from the eruption site, to visit the volcano and take a 'selfie'. Believe me, this was an incredibly dangerous and stupid stunt, as any wind change could have killed the whole group.

There truly is not a whole lot else to report until something else changes with Bárðarbunga. But I did want to give a quick catch up and synopsis of what's going on there. 

Wednesday, October 29, 2014

Cerro Negro de Mayasquer Has Large Quake Swarm

On the Columbia-Argentina border, a volcano that has not had an eruption for over quite some time. There is a report of activity in 1936, however this is now assumed to have been from nearby Reventador volcano. The volcano itself does not appear to have been active during the Holocene, so it would be another in a line of eruptions of volcanoes with no historical eruptions.

Fumeroles, and hot springs are found on the volcano.

The Smithsonian GVP reports the following:

"Cerro Negro de Mayasquer | Colombia-Ecuador | 0.828°N, 77.964°W | Elevation 4445 m

On 20 October Servicio Geológico Colombiano (SGC) reported that a M 5.8 earthquake, the largest to date, occurred in the vicinity of the Cerro Negro de Mayasquer and Chiles volcanoes at a depth of less than 10 km. The event was felt to the N in Pasto (Colombia) and to the S in Quito (Ecuador). On 21 October SGC raised the Alert Level for the volcanic complex to Orange (level 3 of 4) noting that a seismic swarm characterized by 4,300 earthquakes was detected in an 18-hour period. Hypocenters were located 1-4 km SW of Chiles volcano at depths of 3-5 km and local magnitudes between M 0.2 and 4.5. Inhabitants felt 11 of the events. On 22 October a report noted that the total number of earthquakes recorded on 21 October reached 7,717, which was the largest number of earthquakes recorded on one day since the installation of a local seismic network in November 2013. Several swarms have occurred in the area since February 2013."

Since this report, around 12,000 people have been evacuated as the number and magnitude of quakes have sharply increased since October 24th. It is looking likely this volcano will erupt.

The South American West Coast has had several eruptions from long-dormant volcanoes recently. Chile's Chaiten volcano erupted after more than 8,000 years of dormancy in a large rhyolitic explosion. There has been seismic activity recorded at Machin volcano in Columbia, which has been dormant for 8,000 years. Other long-dormant or presumed extinct volcanoes have also erupted in Africa and the Red Sea, such as Nabro volcano in Eritrea (which was presumed to be a dead Pliestocene volcano), and Jebel Zubair/Jebel Al-Tair volcanoes.

This only means that no volcano should ever truly be deemed 'dead', especially if it is in line with, and surrounded by other active volcanoes.

Friday, September 12, 2014

Bárðarbunga Volcano Disrupting Other Volcanoes?

Tungnafellsjökull volcano rumbles, Askja volcano quakes, and Herðubreið shakes. What is going on in Iceland? Bárðarbunga's new activity and magma intrusion does indeed seem to be 'squeezing' neighboring volcanoes into a state of higher seismicity. To the West of the Bárðarbunga caldera lies a Pliestocene-Holocene volcano called Tungnafellsjökull, which contains a large caldera, and shield volcano. It has no record of activity during human occupation of Iceland, and it's uncertain whether it has erupted in the last 8,000 years.

Askja volcano, to the North, and neighboring Herðubreið volcano, a Tuya, are also experiencing heightened quake activity. Askja is responsible for one of Iceland's largest eruptions in historical time, which created a caldera (which is now filled by a lake), and fissure eruptions on its flanks. Herðubreið has not erupted in historical time, yet now there appears to be persistent seismic disturbances happening beneath its summit.

So what could be happening? Well, a few things really, but none of them appear to be precursors to imminent eruption... yet...

Tungnafellsjökull is characterized by the Smithsonian GVP:

"The Tungnafellsjökull central volcano, located immediately NW of the massive Vatnajökull icecap, contains two calderas. One is largely filled by the Tungnafellsjökull glacier, and the other ice-free caldera located to the SE contains Pleistocene rhyolitic lavas. The 1535-m-high Tungnafellsjökull volcano is largely of Pleistocene age, but postglacial flank fissures on the NE side have produced young basalts. The Hágöngur central volcano to the SW is part of the Tungnafellsjökull volcanic system."

Earthqauke activity at Tungnafellsjökull has picked up since the dike intrusions, eruptions, and unrest at Bárðarbunga, leading some to believe that it could be 'reactivated' as a result of the crustal pressures. Indeed, magma can remain hot and ready in a volcanic system for a long time, slowly cooling into what's known as 'crystal mush'. In this state, the magma is more viscous and thick, and not typically ready to erupt unless it gets new magma injection... but what happens when a magma chamber gets 'squeezed', as I suspect is happening. Does it build pressure, causing rock fracture, and possible unrest? I see this scenario as most likely... but so far there has not been any opinions generated by Iceland volcanologists (they tend to shy away from 'opinion' and rely on data).

When a large rush of magma from what is probably the main magma plume in Iceland starts moving mountains, you can bet there will be some activity in other parts. Whether or not this generates eruptions in other volcanoes around Bárðarbunga is anyone's guess right now. Typically volcanoes require fresh magma and immense pressure to erupt, but I've never seen an eruption quite like the one in Bárðarbunga, with such rapid ascent of magma dikes and sustained lava flow. Only Kilauea tends to erupt this way, and like Iceland, its volcanic system is attributed to a magma plume or hot spot. The difference is Iceland's hot spot sits on the mid oceanic spreading ridge between the North American and European plates, which spread apart, making eruptions in Iceland potentially more drastic.

In any case, the situation in Iceland is highly dynamic at this point. Good place to keep your eye on for now.