Well, at least it looks like Japan is aware that we’ve had a shortage of volcanoes in the last century and maybe, just maybe, they need to be ready for that changing.
Frankly, given the known historical level of volcanism, globally,. that fact that when it all dramatically slowed in the 1900s, we got somewhat warmer really ought not to surprise anyone. My expectation is simply that we will return to more historical average levels. What where those? Enough to have tropical and Pacific islands depicted with smoking volcanoes more often than not. Enough to have a “Year without a summer” in 1816-17. Yeah, not a common event; but not the sort of thing to be gone for a century and just call that “the new normal”.
So can Japan serve as a “model” for that chunk of history? Can we look at it, and see the pattern? Or would somewhere like California or Mexico be better? FWIW, when I was a kid there were still a fair number of “old folks” in my home town who remembered when Mount Lassen had last erupted ( begun in about 1914 for a half dozen years ). We used to go out in the countryside and see large lava rocks that were ejected from the volcano (mostly in prior ancient events ) and I climbed to the top of Lassen (it is still steaming and smoking, just a bit…) Yet my whole life I’ve been waiting for it to “do something” again. On the way to Oregon, the highway passes directly past a ‘relatively new’ cinder cone. A very nicely formed pile of dark black rubble. Yet it is thousands of years old. While California is active, the time scale of the activity is just too long to use easily, and the side of the activity in recent centuries has been too small. Complicating it even more, there were not a lot of written records until the last 150 years. Barely time for a belch in ‘volcano years’.
But Japan has a long recorded history, lots of geologists going over the place, and even more active geology. What might they be thinking?
Study: Massive volcanic eruption in the cards for Japan
December 03, 2012
By TAIRIKU KUROSAWA/ Senior Staff Writer
Japan should brace for a catastrophic volcanic eruption at some point, say experts, citing a massive buildup of magma at many of the nation’s 110 active volcanoes.
The last particularly serious eruption in Japan occurred in 1914, when Mount Sakurajima in southern Kagoshima Prefecture blew its top.
According to study by volcanologists, Japan, which lies on the Pacific Rim of Fire, has been shaken by more than 1,000 volcanic eruptions over the past 2,000 years.
OK. 110 Active volcanoes is a nice large sample size. They had a ‘serious’ eruption in 1914 when California was having a small entertaining one, so better indication strength. Interesting to note that the Ring Of Fire was active on both sides on the same date, and that both areas are less active now. These places are connected… Remember that Cascadia had a Great Quake related in time to when Japan had a Great Quake and Mt. Fuji erupted.
So there’s also been a ‘teleconnection’ between great quakes and volcanoes on both sides of things. I suspect that there is a gravitational / tidal driver of it all, and related to the longer term variations in lunar tidal forces. (There is not just a 1 month cycle, but a 19 year cycle, and even cycles out to 1800 years when other orbital changes are included.)
But back at that article; what is being noticed in Japan?
“The possibility of a major eruption in the future is real,” said Yoichi Nakamura, a professor of volcanology at Utsunomiya University who has been analyzing volcanic eruptions with a team of researchers.
So this isn’t just ‘some guys’ making stuff up. This is degreed educated guys making stuff up ;-) But seriously, the Japanese researchers take their work seriously and are very much honor bound. I have some fair confidence that they have thought through what they are saying and that it is highly accurate.
Of the 110 active volcanoes, the agency monitors activity of the 47 around the clock to detect signs of an imminent eruption.
When offshore Mount Sakurajima erupted, it spewed out so much lava that it created a land bridge with the Osumi Peninsula. Volcanic ash even fell on eastern Japan.
The researchers said seismic activity surged at 20 active volcanoes around Japan, including Mount Fuji, after the magnitude-9.0 Great East Japan Earthquake struck last year.
Normally, when a great quake like that happens, the subducting plate melts, adding more magama and eventually leading to move volcanic activity. That cycle is measured in decades to centuries in some cases. Shorter term, there can be an uptick in volcanic activity at sites ‘ready to go’. “Why” is speculative. From simple rock displacement to weakening structures to cosmic flux to tidal forces to… but it’s all a guess as to “why”. Yet the observable just is…
Over the past century, volcanic eruptions around the world were apparently triggered by magnitude-9.0 or stronger earthquakes that struck several years earlier.
So that is why I care about Great Quakes… There have also be correlations found between great quakes on one side of the planet and volcanoes on the other. The vibrations can ‘focus’ on the exact opposite side of the planet, or the crustal displacements can cause stress changes around an entire plate, such as the Pacific Plate. In short: a “9” anywhere is an alarm bell everywhere. We’ve had 9 scale events in Indonesia, Japan, and Chile. That means volcanoes ought to start erupting…
Particularly worrisome, he said, was a lack of data pointing to a reduction in magma. In the absence of a really huge eruption for a century suggested there was a massive buildup of magma, which at some point will inevitably spew from a volcano with tremendous force.
According to the study, 1,162 eruptions have occurred in Japan over the past 2,000 years. Of these, 52 were major events that spewed a massive volume of ash and lava over a short period. It amounts to a large-scale eruption occurring every 38 years.
Records show that three volcanic eruptions in the 17th century, including one at Mount Hokkaido-Komagadake in Hokkaido in 1640, spewed out the equivalent of 1 billion cubic meters of ash and lava.
Two similar eruptions occurred in the 18th century, one of which involved Mount Fuji in 1707.
Over the course of the last Century, not much has happened. Could that dearth of aerosols have had any effect on the long term weather? It hasn’t been just a Japan thing, either. As I noted for California, we’ve had 100 years of “not much”. The stereotype of the smoking volcanic island is also fading. Yeah, we had “Joe V.S. the Volcano”, but that movie was a tongue in cheek parody of the prior stereotype. In the 1800s, it wasn’t a stereotype, it was an observable. (Especially in Indonesia).
For Japan, their record is about one significant eruption per 2 years. Large scale events 1:38 years. Yet we’ve had 3 times that long with “never mind” as the observable. Think that matters to the weather and temperature history? I do.
There were 562 instances of medium-scale eruptions, or one every 3.6 years.
These included the eruption of Mount Unzen-Fugendake in Nagasaki Prefecture in 1991 and the eruption of Mount Usuzan in Hokkaido in 2000.
Of the 1,162 eruptions, the 47 volcanoes consistently monitored by the Japan Meteorological Agency represent nearly 90 percent of the activity, or 1,012 of those events.
So “medium scale” and we’re at 1:3.6 years. Or 2:7 roughly. What’s been happening ‘lately’? 2 of them. 9 years apart. (Then what I presume is a 12 year lull.)
What all this looks like to me is a system that “took a nap” for 100 years, and is now starting to wake up. Not fast, but waking all the same.
This site is something of an ‘advocacy site’ with a clear anti-nuclear agenda due to the nuclear reactor damage that happened. Yet it has a couple of interesting photos of Mt. Fuji. In the middle of winter, in one month, the snows melted. They ask / assert that it might be ground heating.
Though it was the season when Mt. Fuji has the most snow, snow is already disappearing.
From December to January, most of the snow melted only within a month. Mt. Fuji is heated.
Citizens near Mt. Fuji talks they haven’t seen such a thing.
They list this site as the source ( it is in Japanese ).
It looks to me like they have the better photos.
Not a whole lot of “message” in this posting. Just an observation. I expect we’ll see Mount Fuji erupt in the next decade. Two at the max. I expect we will see significant increases in volcanic activity globally. Geological things are slow, though, so it can be decades as a ‘ramp up’ becomes noticed, and even longer for that to be excepted as a ‘trend’.
I don’t see this as in any way ‘catastrophic’. More of a ‘return to the norm’. Vanuatu is having a large number of 6 scale quakes with the occasional 7 thrown in. I’d expect to see more volcanic islands waking up a bit too.
All in all, it ought to be an interested time, going forward. Just the kind of thing to look forward to in the coming year (s).
We’ve even got a ‘weird’ underwater volcano off the end of Baja California:
Mostly they think it weird due to the rhyolite
The volcano is primarily rhyolite and a silicic lava called dacite, said MBARI geologist Jennifer Paduan. “To find this along a midocean ridge is a total surprise,” she told OurAmazingPlanet.
Usually sea floor spreading makes basaltic lavas.
I’m not all that surprised, though, since this is a place where a spreading zone starts to go under the continent, so the continental shelf is in the way. Still, we’ve got an activation of the ‘spreading zone’ making a volcano. Just a bit off shore. So I’m not going to be at all surprised if the ‘trend’ continues on up to Death Valley (caused by sinking in that spreading zone) and Long Valley / Mammoth Mountain (where there has been a notable increase in earthquakes).
I’ve been waiting 1/2 a Century for a nice little volcano somewhere in California to wake up and spout. With any luck, this next year will see that particular itch scratched. Anywhere from the Oregon Border (Cascades) through Shasta and Lassen and on over to Mono and south from there through Death Valley and Mojave, on to the Salton Sea area. Any of it can pop a rumbler and spout a bit of glowing goo. Yet all we’ve had in my lifetime has been some mud pots and fumes. But things are looking up, at last.
With that, may everyone have a Sparkling Smoking-Hot Happy New Year!!!
(OK, ok… yeah, a long way to go ‘around the mountain’ for that… but it was worth it, wasn’t it? ;-)