Tuesday, December 31, 2013

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.

Monday, December 30, 2013

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.

Monday, December 23, 2013

El Hierro Seismicity Picks Up

Could the Canary Islands volcano El Hierro be gearing up for round two of its renewed activity? Recent reports from Earthquake-report.com are indicating that magma injection is occurring again at the island. Over the last couple of days over 58 earthquakes concentrated near the site of the offshore eruption have occurred, and uplift of nearly 2cm was detected. This indicates magma is travelling to a shallower level, and could be a precursor to eruption. This however IS speculation, as many magma injections do not lead to an immediate eruption (see Mt Fuji!).

El Hierro volcano was up until recently, a fairly quiet volcanic island, and had not had any eruptions since the late 1700's, but this all changed in 2011 when the island spawned a new submarine cone off its SE coast near the town of La Restinga. Indeed, it was this volcanic eruption that was my initial inspiration for creating this blog, as I was reading tons of information in very bad English. At the time it was my hope to be live-blogging the eruption with footage of a Surtseyan eruption (an eruption that begins as submarine, but ends up creating a new island above water). Alas, we were gifted with a prime example of a Serretyan eruption.

The small eruption of the submarine cone however does not appear to have been the last we will hear from this island in the near future. As new magma enters the system and inflates the island, it is likely that at least at some point a fracture or conduit will form that allows the magma to escape to the surface. Obviously it is everyone's hope that when or if this does occur, people will have all the warning they need to get out of mother nature's way.

The previous eruption lasted for several months, nearly a year, with on and off activity, and waves of speculation as to how the volcano might continue its eruption. In some cases it was theorized that several submarine eruptions had occurred, however this was never conclusively proved.

This is one of my personal favorites in terms of volcanoes, not just because it's partly responsible for this blog int he first place, but because of the fact it was one of the first volcanoes to be observed before, during, and after the eruption from nearly every media angle possible. Seismographs, tilt meters, webcams, bathymetric scans, ROV footage of the plume from underwater, the first live observation of a Serretyan eruption and associated 'lava balloons'... it was really something cool to see for us volcano nerds out there. 

Maybe 2014 will give this blogger another present! Stay tuned!

*****UPDATE*****

More recent news is available, please go to http://volcanoscience.blogspot.com/2013/12/el-hierro-volcano-alert-raised-to-yellow.html

Friday, December 13, 2013

Comment Policy Changed

While I'd like a lively discussion on the topic of volcanoes, I have been receiving a higher than normal amount of 'anonymous' comments that are either offensive, or spam. So anonymous comments are no longer enabled, you will need to have a Google+, or OpenID account to comment. While I am all for people expressing their opinions, I think its important to own what you say, and to keep it civil (and non-commercial). Thanks for understanding.

Wednesday, December 11, 2013

New 'Supervolcano' Discovered in Utah

The North American continent is home to several so-called 'supervolcanoes' (a term that is lamented by many geologists and volcanologists) such as Wyoming's Yellowstone Caldera, California's Long Valley Caldera, and New Mexico's Valles Caldera. Now, Utah joins the list of states that are host to some of the biggest eruptions in Earth's history.

After 30 years of intense research, collecting rock samples, creating gravimetric maps, and studying ash layers, geologists have zeroed in on the epicenter of what is thought to be one of the largest eruptions of all time in the US, bigger than even the largest eruptions of Yellowstone. But don't worry, scientists say that it is unlikely to ever erupt again, unlike Yellowstone, or Long Valley (the Valles Caldera also has the potential to reactivate, but is generally the quieter of the three). The magmatic system that produced these eruptions has long since become extinct.

The eruption was so large, that ash layers can be recorded as far away as Nebraska! Wildlife and plants from over 30 million years ago were preserved in these layers.

The epicenter is in an area known as Wah-wah Springs, in Western Utah, and extends to Eastern Nevada. This would make it one of the largest supervolcanoes on the planet (discovered so far at least), and one of the largest in North America.


Screenshot of Utah/Nevada Supervolcano eruption area and associated caldera from KSL.com web report.

Many mountain ranges and volcanic rocks in the area were associated with the White Rock Caldera, and it remains to be seen whether or not this volcano is related to it. Utah and Nevada lay on top of the Rio Grande Rift, an area of the United States that is spreading apart, rather than plates slamming together and subducting like the Pacific Plate and its associated Pacific Ring of Fire. Volcanoes along this rift do not erupt as often as their pacific neighbors, but when they do, the eruptions are typically larger and more devastating, and obviously foster the creation of some mantle plumes (although in the arena of science, this would need to be more thoroughly researched, as mantle plumes are still somewhat controversial, despite a lot of evidence).

This recent discovery adds to ever increasing data about the eruptive history of our planet, and will undoubtedly fill in some gaps and resolve some mysteries that have puzzled geologists for some time. Discoveries such as these are always some of the coolest geological news in my opinion!







Tuesday, December 3, 2013

Etna Steals The Show, Japan Gets New Island


There is not a lot of 'new' eruptive activity going on lately, however Sicily's Mt Etna continues to put on some breathtaking displays of lava fountain activity lately. While this is not unusual for Etna, being one of the most active volcanoes on Earth, the shows are quite spectacular.

                                     

And while Etna steals the show, Japan's volcano, Nishino-shima has had a surprise eruption off its coast that started as a submarine eruption, but birthed a new island into existence (much like we were HOPING would occur live on webcam at El Hierro! But alas...).

Other than these occurrences, it is a slow month/week/year for volcanoes. The currently erupting volcanoes are sadly, the usual suspects!