Showing posts with label Mt Fuji. Show all posts
Showing posts with label Mt Fuji. Show all posts

Thursday, September 6, 2012

Scientists Warn Further About Mt Fuji, Japan

While it was never confirmed if Mt Fuji ever had a minor eruption which resulted in the creation of a new flank crater, it is now confirmed that the recent quake activity in the area (A 9.0, 6.4, and 5.0) around Mt. Fuji has indeed increased drastically the amount of pressure in the magma chamber of the iconic Japanese volcano. The current pressure in the chamber has reached a high level of 1.6 megapascals, which Japanese scientists are quoted as saying "is not a small figure". It has been noted that many eruptions occur with a mere 0.1 megapascals of pressure in the chamber.

Steam activity, small water eruptions, and large holes that are emitting volcanic gasses are starting to occur in the vicinity, and the crater is fuming (However I have only been able to cite this from the linked Wired.com article, and have seen no real evidence of this with cameras, video, or other sources, so don't take my word for that).

This is the most activity in the area since a swarm of low-frequency quakes occurred in 2000-2001, and began after the large 9.0, and 6.4 quakes. With the current activity, it is quite evident that the earthquake has re-pressurized the magma chamber. It is quite likely that this will remain the case until more seismicity, which is highly likely in the area, occurs and puts more pressure into the system.

One scientist has gone so far to say that he expects an eruption from Fuji now within "the next three years". Another major cause for concern about the volcano is that a new 34km long fault line was discovered after the major 9.0 2011 quake, which runs directly underneath the volcano, and if destabilized, could result in partial or total collapse of Mt. Fuji.

It is my opinion that the current activity will probably not lead to an imminent eruption (scientists have to be careful with what info they put out, you don't want to cause panic, but you also don't want to be unprepared, and erring on the side of caution is what saves lives), but you will probably see a lot of hydrothermal activity, including but not limited to, minor phreatic eruptions, increased fumerole action, and possibly some deflation/inflation (DI) events. The activity at the volcano is quite similar to the type of activity now being seen at Mt. Iliamna volcano in Alaska, which also experienced a minor magma intrusion, but has merely increased its gas emissions and level of small seismicity. Iliamna has not erupted yet, but has been on AVO's 'watch' list for nearly a year now.

An eruption from Mt. Fuji today has been estimated at a damage cost of up to ¥2.5 trillion ($3.25 billion) to the Japanese economy, and could also cost over 300,000 lives. It is critical that those living near this volcano understand the dangers, and have an evacuation plan as well as supplies they can rely on in the event this does occur. The volcano, at its full fury, is capable of massive levels of destruction to the immediate area, and includes in its arsenal the potential for pyroclastic flows, landslides, lahars, phreatic eruptions, fissures, pyroclastic cinder cones, and fast flowing pahoehoe basalt lavas.

The last eruption in 1707 blasted out a large crater on the Eastern slope of Fuji, and deposited ash as far away as Tokyo. Many buildings and towns surrounding the volcano are built on the lavas and ashes of this eruption. Due to the extensive history and record keeping of Japan, most residents are quite aware of the dangers of Fuji, and typically take any evacuation order very seriously, but pyroclastic flows are a hard thing to outrun when they can reach speeds of up to 280mph, so early warning is the best possible scenario.

I will also to see if there are any other credible sources to confirm what Wired.com is claiming in regards to steaming and gas emissions (however they did not cite a source for this claim). Its actually possible that they could be using my blog as the source for this, as I was among the first sites to report the initial supposed 'emissions' from Fuji, which I was never able to confirm save one obscure report in Japanese news.

Scientists will more than likely step up their monitoring and analysis of Fuji in the mean time, and keep a close watch on its goings-on.


Wednesday, March 14, 2012

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.

Saturday, February 18, 2012

Japan's Mt Fuji May Be Preparing To Erupt

Volcano-Report.com is reporting that Japan's Mount Fuji (Fujiyama) volcano is showing signs that it is getting ready to erupt. While translating Japanese to English using Google translate leaves much to be desired in terms of readability, the news story (in Japanese) appears to be saying that fumerolic activity and steam emissions have increased, with an unclear anecdote about a 50m wide "new" crater. The only picture I was able to find (below) was a bit grainy, and appears to be showing a snow-less crater on a very snowy mountain. I cannot personally confirm whether or not this is actually a picture of Fuji as there are no other identifiable landmarks in the photo. 



Image from Japanese media of a supposed "new" crater on Mt. Fuji (Fujiyama)
Following the Japanese 9.0 megaquake, there was a magnitude 6.4 quake slightly West of Fuji at it's base. Other quakes of smaller magnitudes (4.0-5.5) have also struck within 50km of Fuji.

While it is unclear from the photos if this is truly a new flank eruption of Fuji (I imagine if the weather was cloudy that people might not notice, but the volcano is easily seen from a great many cities in Japan from a great many angles), the photo does not seem to have an ash layer over the snow. The recent eruption of Mt Etna in Sicily occurred in a supposedly similar fashion, with a cone building flank eruption producing lava flows on a snowy landscape. The ash was clearly visible on the snow for many days.

Mount Fuji last erupted in 1707, in what is considered its largest historical eruption. This eruption was characterized by a massive flank explosion that left a very large crater on the East side of the mountain. This eruption devastated villages nearby, and was strong enough to cover Tokyo with ash. Many current communities in the area are actually built on thick historical lava flows from this event. Nobody alive has ever seen Fuji erupt, but they all know the stories from well-kept records of that period, and the last eruption was very well documented in Japanese historical archives.

Over 100 cinder cones and vents dot the landscape around Fujiyama, highlighting the unpredictable nature of eruptions from this volcano. Fuji could start out with a cone building phase, and enter into a more explosive phase, or this could be all that happens at Fuji for the next hundred years.

If any new information comes available, I will update this blog immediately.