Greece's Santorini Volcano Inflating

Santorini, Greece's famed caldera volcano is inflating according to GPS instruments and volcanologists. The inflation has also been accompanied by increased seismicity, and volcanologists state that the magma chamber has grown by about 500 million cubic feet. Scientists are quick however to point out that this does not mean an eruption of Santorini is imminent, and even if there were to be an eruption, the conditions for a caldera-forming  eruption that wiped out the original Santorini island and the Minoan civilization are not present.

An eruption at Santorini however could be disastrous for the Greek country, which is struggling financially and is barely getting back to solvency.

Any eruption at Santorini would likely be further building of its central island cone, or submarine in nature, but could easily end up as a powerful explosive event which could devastate the harbors and anchorages within the caldera, and would definitely be disruptive. The last eruption of Santorini was in 1950, and produced a small lava dome and flow on the middle island of Nea Kameni. The previous eruption in 1866 produced explosive eruptions which did result in some injuries to scientists observing the eruption (rather closely and dangerously by today's standards).

There is no chance of an eruption on the scale of the famed Minoan eruption, due to the fact that it takes a supervolcanic or caldera forming eruption hundreds of thousands of years to really recharge and create the conditions for such an event.While an eruption at Santorini would be hugely disruptive to residents and tourists alike, the most likely scenario is that it will simply end up being scientifically fascinating, and benign. Time will tell however, and the world will continue to watch.

6.9 Magnitude Quake Strikes Off Japan Coast

A 6.9 magnitude earthquake struck off the coast of Honshu, Japan near the location of last year's deadly quake and tsunami. Six large aftershocks have occurred so far in at or near the epicenter ranging from 6.1 down to 4.6.  More quakes shook the Tokyo region later in the day. The quakes off the coast of Honshu generated a small 8-inch high tsunami. No damage was reported.

This series of quakes (while rather common in the region now) comes almost exactly one year (plus a few days) after the devastating magnitude 9.0 magnitude quake.The 9.0 mega-quake damaged the Fukushima nuclear plant resulting in a meltdown and widespread radiation which has devastated a large portion of Japan and has made the land uninhabitable. Further damage was visited on Japan by a 30-40ft high tsunami wave that destroyed large portions of Japans coastal cities.

The subducting plate is now in nearly continuous motion since that event, with large quakes being a fairly regular and almost daily occurrence. it is regular for magnitude 5.0 and up quakes to hit the region along the subducting plate.

Japanese scientists are also closely watching the restive Mt.Fuji for further signs of unrest following a series of quakes in the area, and recent (very unclear) reports of "a new crater" on the NE side of Fuji (however this was NEVER confirmed), as well as reports of new fumeroles.NONE of these reports are confirmed, and translation from Japanese to English via Google translate is worthless. Volcano-report.com has however picked up the story, and I also wrote a blog earlier last month about this report, gathering all the information that I could (which wasn't much).

In any case, expect Japan to continue to be a hotbed of earthquake and volcanic activity for quite some time.

Japan's Sakurajima Volcano Has Violent Explosion

The Sakurajima volcano in Japan had it's most violent explosion since 2009, Japanese media and other sources are reporting. Japan's most active volcano in recent years, it had completed the year 2011 with the highest number of explosions on record since people began counting. Activity at the volcano shows no signs of slowing down.

Sakurajima is a complex stratovolcano with many vents, only a couple of the vents have been active in historical time. the volcanic complex is constructed within the Aira caldera, a massive caldera that formed about 22,000 years ago. Sakurajima is a post caldera cone, and has seen much activity throughout human history.

The Smithsonian GVP's summary of Sakurajima is as follows:

"Sakura-jima, one of Japan's most active volcanoes, is a post-caldera cone of the Aira caldera at the northern half of Kagoshima Bay. Eruption of the voluminous Ito pyroclastic flow was associated with the formation of the 17 x 23-km-wide Aira caldera about 22,000 years ago. The construction of Sakura-jima began about 13,000 years ago and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kita-dake summit cone ended about 4,850 years ago, after which eruptions took place at Minami-dake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76."

Alaska's Cleveland Volcano Has An Explosion, Iliamna Rumbles Away

Alaska's volcanic activity is picking up. Mount Cleveland was reported by multiple news sources and AVO as having had an explosive event on Wednesday, although the cloud is reported to be far less in height than the 20,000 meters it would take to institute a no-fly zone. AVO stated "A small, short duration explosion was detected from Cleveland Volcano on distant seismic stations and infrasound arrays. The time of the explosion was approximately 4:05 UTC March 8 (7:05 PM March 7, AKST.) Weather cloud conditions prevented the detection of an eruption cloud in satellite images or visual observation of the summit. This explosion was similar to recent small events that occurred in December 2011 and produced small ash clouds that dissipated quickly and did not affect air traffic. At this time, no further activity has been detected."

And as Cleveland volcano slowly plods along with what seems to be akin to a slow motion, low explosive eruption, a volcano I have mentioned in a previous post, Iliamna, is showing more signs of dike intrusion. Heightened seismicity including very shallow quakes under the restive volcano, which has no recorded history of eruptions during human habitation in Alaska, is causing AVO to suspect what I have said in the past, that Iliamna is waking up, and is preparing to erupt. The last radiocarbon dates for any eruption at Illiamna are thought to be 140-300 years ago. A record number of seismic events (for Illiamna) is occurring, and AVO scientists are planning a fly by to check for any visual signs of a change in activity. They will be checking for steaming, fumeroles, melting ice, etc.

Today alone, Illiamna has had over 40 quakes, some of them not-so-small, with the largest being a 3.2 magnitude beneath the summit, at a depth of only 2.0km, closely followed by a 3.1 quake at a shallower depth of 1.2km. It is my humble opinion that Illiamna is indeed ready to erupt, and this will occur either this month, or this year. We will wait and see, but so far I have been right about this volcano, and as far as I know, I was the first to report on its unrest aside from AVO noticing the tremor waves (I could not find anything or any other news that was posted before this article). Maybe I'm on to something!

Current seismic tremor at Iliamna Volcano, from AVO website.

In any case, the amount of quakes today alone make me almost think an eruption is already occurring. If it isn't it certainly might very soon, and we have very little idea as to how this volcano will erupt, given that it has never been witnessed in eruption (the only info we have is forensic). The picture below shows the current (last 24 hours) swarm of quakes, while the quakes in Yellow have occurred within the week. 

Image from Google Earth with USGS real-time quake overlay.

Iliamna is a stratovolcano, common for the US's Pacific Ring Of Fire volcanoes, and is most likely capable, like most of its neighbors, of large explosive events. An eruption at Iliamna will most likely cause some disruption to air travel, as well as ashfall on nearby towns, however the immediate area surrounding the volcano is not populated by any permanent towns. This volcano will likely not be able to directly kill anyone, thankfully. Time will tell on this, but it is looking more and more like an eruption at Iliamna is imminent.

As of now, AVO has NOT raised the alert level for Iliamna, however if I were them I would at least consider at this point raising the alert level to "Yellow" (watch). It would be a tragedy if this volcano were to erupt as an airplane is flying over, much like the incident in the 1980's when Mount Redoubt suddenly blew and nearly caused a fatal crash.

The Smithsonian GVP says this about Iliamna:

"Iliamna is a prominent, 3053-m-high glacier-covered stratovolcano in Lake Clark National Park on the western side of Cook Inlet, about 225 km SW of Anchorage. Its flat-topped summit is flanked on the south, along a 5-km-long ridge, by the prominent North and South Twin Peaks, satellitic lava dome complexes. The Johnson Glacier dome complex lies on the NE flank. Steep headwalls on the southern and eastern flanks expose an inaccessible cross-section of the volcano. Major glaciers radiate from the summit, and valleys below the summit contain debris-avalanche and lahar deposits. Only a few major Holocene explosive eruptions have occurred from the deeply dissected volcano, which lacks a distinct crater. Most of the reports of historical eruptions may represent plumes from vigorous fumaroles east and SE of the summit, which are often mistaken for eruption columns (Miller et al., 1998). Eruptions producing pyroclastic flows have been dated at as recent as about 300 and 140 years ago (into the historical period), and elevated seismicity accompanying dike emplacement beneath the volcano was recorded in 1996."

I will probably post an entirely separate article should Iliamna decide to erupt.

*****UPDATE 3/11/2012*****

AVO has raised the alert level at Iliamna to Yellow. They posted the following statement:

"Over the past three months the earthquake rate at Iliamna Volcano has steadily increased and now exceeds normal background levels. Although it is not certain that this sustained increase in earthquake activity represents the movement of magma at depth, it is a significant change and AVO has increased the Alert Level to Advisory and the Aviation Color Code to Yellow. The current activity does not mean an eruption is imminent or certain. A similarly energetic episode of seismic unrest from September 1996 to February 1997 was likely related to the intrusion of new magma at depth, but an eruption did not occur."

It Is Official: El Hierro Eruption Has Ended

INVOLCAN has declared the eruption of El Hierro to be over, and the alert status of the island has been lowered from Red to Yellow. The village of La Restinga can finally open its doors to tourists again, however maritime activity is still restricted due to probable degassing, and swimming in the water is still off limits pending a chemical analysis of the water to determine its safety. Sea life has already begun to repopulate the area, a good sign for the fisherman of the village.

The eruption at El Hierro was preceded by a lengthy period of volcanic earthquakes, which were used to size up the magma chamber. The island was on Yellow alert for a long time, before a "jacuzzi" was spotted in the ocean, and harmonic tremor increased. The eruption of the underwater cone "Bob" started as an underwater fissure eruption, eventually resulting in a cone building event. Several collapses of the main vent stalled the eruption, which stopped and started several times. On occasion, floating "Lava Balloons", or gaseous bubbles encased in molten rock, would float to the surface and emit steam, and sometimes flames once the bubbles burst and allowed oxygen to interact with the heat. This however was as exciting as the eruption got.

For about a month now, the eruption has all but ceased entirely. Harmonic tremor has been at low to background levels, and there has been very little if any surface activity since February. This is what led the scientists to declare the eruption over, although their maintaining of alert level Yellow does indeed reflect what many of us know, that activity can resume at any time, and caution is still in order. Some volcanoes have a small cone building event as a precursor to a larger eruption, something that is certainly not out of the question.

Current uplift sensors show the island to be stable, which could mean that the magma reservoir has not deflated, and merely extruded the lava to form "Bob" because it was the easiest path to the surface. Quakes are still ongoing at El Hierro in an area not near "Bob", and it is still worth keeping an eye on the island. El Hierro and the Canaries have been compared to the Hawaiian islands in regards to the type of eruptions it produces. The theory goes that El Hierro, like Hawaii, is a hotspot type volcano. These are highly unpredictable as we have no way of imaging or monitoring the mantle plumes that are though to be responsible for hotspot volcanoes.

It is my guess that activity will pause now for probably months, and either slow subsidence will take place, or activity will resume in another location. It is now a game of wait and see. In any case, I doubt that the residents of El Hierro will ever forget now that they are living on an active volcano, and will be ever mindful of the power that lies beneath their feet.