AVO Upgrades Cleveland Alert To Orange

Alaska's notorious Cleveland Volcano has been upgraded from yellow alert status to orange amid recent explosions from the summit crater. The volcano has been in a state of unrest for several years and has had periods of summit crater dome growth, followed by explosions that destroy the dome, only to restart the process. Typically (during this particular unrest period), Cleveland will have a brief explosion that 'unplugs' the summit, ejecting hot ash and blocky lava, and then change to a period of very slow effusion that builds a plug or dome within the crater. After the dome reaches nearly the rim of the crater, this is when the explosions have been occurring usually.

Alaska Volcano Observatory (AVO) does not have monitoring equipment on Cleveland due to its remote location within the Aleutian Islands chain of volcanoes. They rely on satellite data for the majority of their reports, mainly from MODIS or German satellites. Some seismic signals are strong enough to be detected by other 'nearby' monitoring stations, but it is quite probable that Cleveland volcano is a bit more active than we give it credit for, having had probable explosions that have gone undocumented, or unnoticed.

Currently in Alaska, there are only two volcanoes showing activity of any kind. Veniaminof volcano has gone up and down from Yellow to orange and back to yellow several times in the past year or so, with periodic lava effusion from the summit cone.

In a typical year, at least one or two volcanoes is usually in a state of unrest or eruption, and Cleveland volcano is one of the most frequently active in the chain.

Cleveland volcano does not pose any threat to human populations, but does lay under many air travel routes, so an Orange designation means that air traffic may need to divert to other routes in order to avoid being unexpectedly caught in an ash column, as happened with the 1989 eruption of Redoubt volcano (which also had an eruption in 2009). An airline full of passengers was temporarily disabled as it flew through a column of ash some 45,000 meters in height, causing its engines to choke on volcanic ash that turned to glass within the turbine. Fortunately the plane was able to restart its engines before it would have crashed, and landed safely.

Little Known Palena Volcanic Group In Chile Has Eruption

It appears that on Dec 22, a volcanic group in Chile may have had eruption, possibly for the first time in the historical record. The Palena Volcanic Group, which is described by the Smithsonian GVP as "The Palena volcano group consists of five cinder cones oriented along a NNE trend NE of Melimoyu volcano. The youthful volcanoes, which are named after the middle cone, are Holocene in age (Moreno 1985, pers. comm.)" has not had any confirmed historical eruptions. If this is true, it would mark the first observed activity in this chain of cinder cones.

I went to check out the location via Google Earth, and was only able to visually identify 3 obvious cinder cones, to the SW and NE of where the GVP marker was (Image below) so it is not clear exactly where this eruptive center (if an eruption is occurring) is located. The cones I was looking at look to be monogenetic in nature, heavily vegetated, but pretty fresh looking morphologically.

                                     

Screenshot of location for Palena Volcanic Group with 3 cones identified by marker pins, from Google Earth. 

If this report is true, this would mark the 2nd volcano in recent history with no known eruptions to pop off in less than a decade, after the spectacular and unexpected rhyolitic eruption of Chaiten. However, analysis from volcanodiscovery.com seems to indicate that this may not in fact be the case, as SERNAGEOMIN has failed to identify any seismic signals, or verify any eruption has actually taken place. As stated by volcanodiscovery.com regarding the image (below), while this looks like an ash/eruption plume, it could also have been a wildfire that was mistaken for an eruption. Only time will tell.

Image from Volcanodiscovery.com showing purported eruption in Palena volcanic group (photo: A Gillmore / Twitter)

Judging from the photographic evidence so far, and having lived through a multitude of wildfires here in San Diego, CA, this looks a lot more like a wildfire than it does a volcanic eruption, and indeed, a wildfire on a volcano can and has stirred up older ash from eruptions when it becomes swept up in the fierce fire-driven winds. So what we're looking at could possibly be a combination of wildfire ash, and older volcanic ash. I'll reserve judgment however until the science is in.

If this turns out to be a real eruption and not simply a coincidental wildfire on a volcano, this would be scientifically significant, especially regarding lower Andean eruptions. Recent large quakes along Chile's subduction zone ranging from 7.0-8.8 may have altered magmatic systems for some long dormant volcanoes, which is entirely possible, and could help to explain why some volcanoes in Chile remain dormant for so long, and seemingly randomly wake up.

Indonesia's Mount Sinabung Forces Evacuations

Indonesia's long-dormant Mount Sinabung began erupting earlier this year after initially breaking its silence during a period in 2010, and has now increased its level of activity so drastically that over 19,000 people have had to be evacuated. Mount Sinabung lies around 20 miles NNW of the famous Toba super-volcano. The irregularly shaped stratovolcano has had minor fumerolic activity prior to 2010, so it was known that it would probably erupt in the future, however there had never been any confirmed historical reports of eruptive activity before then.

Mount Sinabung had a massive eruption yesterday, sending a plume of gas and ash up to 3km skyward, prompting Indonesian officials to issue air alerts, and subsequently evacuate nearby populations to evacuation centers.

Indonesia is home to one of the largest concentrations of active volcanoes in the world. In any given year, probably 5-15 volcanoes are active simultaneously in the elongated archipelago. Some of its volcanoes are truly the biggest killers of all time, with famous eruptions like the ~75,000 B.C. super eruption of Toba, thought to have contributed to a massive die off of the human population that left a mere 5,000 or so survivors, to Tambora, one of the largest historical eruptions ever recorded and responsible for the famed 'year without a summer', and the infamous eruption of Krakatoa (now Anak Krakatau, "Child of Krakatoa") which destroyed a large island and killed over 36,000 people by way of pyroclastic flows.

Only the more recent eruptions of Novarupta in Alaska, Rotorua in New Zealand, and Pinatubo in the Philippines have come close to the larger Indonesian eruptions.

Indonesia lies on the Pacific Ring of Fire and is home to very frequent earthquakes, eruptive activity, and other disasters. In 2008, a mega thrust earthquake killed over 200,000 people with its super-destructive tsunami and associated damages. It is more than likely one of the least 'stable' geologic places on the planet, aside from possibly Japan, which also recently experienced a deadly and disastrous mega-thrust quake that caused a devastating tsunami, and provoked a nuclear power plant meltdown at Fukushima-Daiichi.

El Hierro Volcano Alert Raised To Yellow

It seems as if PEVOLCA has decided to raise the alert level at El Hierro yet again to yellow after a spate of larger earthquakes measuring up to 5.1, and inflation totaling about 3-4 inches has occurred on the island volcano. earlier this week I had reported that Earthquake-report.com's El Hierro blog was noticing a sharp increase in deformation and seismicity.

This swift a rise in seismicity and deformation is attributed to new magma injection, but whether or not it will again find its way to the surface remains to be seen. It is however becoming more and more likely that this is the case if the trend continues. The inflation of the island at its current state is greater than when it had its offshore submarine eruption off the coast of the fishing village called La Restinga.

The eruption was closely watched by scientists, and geeks like me, who were 'hoping' for the eruption to transition from the submarine Serretyan phase to a more prominent island building phase called a Surtseyan eruption (after the volcano Surtsey in Iceland, which was one of the first islands to be observed in its moment of creation by modern volcanologists). The web camera set up by Earthquake-report.com, and some others were a source of spellbinding anticipation at least on my end.

The deformation so far bisects the island down the middle (as shown in the link), and it is anyone's guess where the island may choose to vent its payload. The area with the greatest uplift (as of today, 3CM in less than a week!) is the NE town of Sabinosa, which is built directly on the remnants of a cinder cone.
The island is dotted by many holocene to pliestocene cinder cones, as well as a collapse-related pseudo caldera, as well as its more recent and older submarine cones. Predicting where the island may erupt is next to impossible, but very hopefully it will erupt in an area that is not populated, or is remote enough for people to evacuate in time. The island does not have a heavy permanent population, but it is a popular tourist spot in the region.

Video showing rockfall on El Hierro.

Some hazards are occurring due to the unrest. Rockfalls are a very real problem for the various roads and homes that lie at the bottom of cliff faces, and some have already ruined or blocked some roads. So even though an eruption isn't occurring, and the quakes are small, it is still creating some problems.

As always, I will keep an eye on this volcano and post updates when they occur. This is one of my very favorite volcanoes to observe lately, so you'll probably see a few more of these posts.

El Salvador's Volcan Chaparrastique Erupts

A long-dormant but still historically active volcano has erupted in El Salvador. Volcan Chaparrastique (also known as San Miguel) had an explosive eruption Sunday marking the onset of activity at the volcano which has not erupted in the last 37 years. The eruption was short lived, and created a gas and ash plume that rose approximately 5km into the sky.

Authorities were quick to alert people not to enter the area, as more eruptions could occur at any time. 5000 people were ordered to evacuate near the volcano.

Reuters reports on the volcanic eruption in El Salvador

El Salvador and its associated volcanoes lie on the so-called "Pacific Ring of Fire", the border of the subducting tectonic plate that makes up the plate underneath the Pacific ocean. The Ring of Fire is home to the most active volcanoes on the planet, the majority of which, like San Miguel, are stratovolcanoes. Typically conical volcanoes capable of great explosive eruptions.

Volcanoes on the Ring of Fire are typically more explosive due to a higher content of water within the magma. This is thought to occur due to subduction from the oceanic plates underneath the parts of the plates that are being uplifted. Water is carried under the plates as if it were on a conveyor belt, and melted when it hits the mantle. This generates magma that is highly gaseous and pressurized, so that when it breaks the surface to become lava, you get these really explosive and ashy eruptions.

It is unclear at this time whether San Miguel will continue to erupt, or if this was just a minor random blast, but I'm sure we'll be keeping our eye on it for a while. Many volcanoes have short lived episodes, and some begin with an event like this and move on to other types of eruptions. It is not possible to know what the volcano will do next, but if there are any updates, I will post them here.