Sakurajima volcano erupts explosively in southern Japan

I bet those people in that mixed bath onsen at the base of the mountain had to flynoutmof there. Must have been a hell of a scene!

They don't call this the ring of fire for nothing.

TheRat: I love that hot spring, but not sure how much they would have seen. Probably would have heard one heck of a lot, though. Pretty crazy video footage with the lightning (like) stuff.

The Japanese archipelago sits atop the Pacific “Ring of Fire,” an arc of volcanoes and fault lines in the Pacific Basin, and has more than 100 volcanoes. The 2014 eruption of Mount Ontake in central Japan killed 57 people.

Yeah, it seems like the perfect place to build over 50 nuclear reactors, doesn't it?

Indeed the volcano is located at only 50 km from the recently restarted Kyushu Electric Power Co.’s Sendai nuclear plant. Therefore it seems to me that people in this country are not really intelligent.

@disillusioned, no one ever said it was a perfect place to build nuclear reactors, there is no perfect place to build nuclear reactors. Maybe you know a better way of supplying electricity to >120 million people in a nation with limited natural resources? Renewables are held up as a Utopian vision of the future but can only provide a fraction of what's required at present.

Fear mongers not knowing anything about the topography around the area.

Craw back from where you came from would you.

@Triring

You want to try to argue with me big mouth? But I warn you. Since I have a PhD in geophysics, you will have a hell of a hard time convincing me that having a nuclear power plant near such an active volcano is a good idea, and that it's not sheer stupidity.

@daito

You have a PhD in Geophysics, and you believe Sakuajima can send lava up over the intervening mountains to the Sendai plant? Did you go to Bakada University?

@daito_hak

Saying you have a PhD isn't a valid argument. You need to post evidence. Otherwise you are just fear mongering.

Fear mongers not knowing anything about the topography around the area. Craw back from where you came from would you.

Do you happen to work for TEPCO? Fukushima perhaps?

@Star-viking

Wow, we've got Einstein here folks. Where did you see that I ever mentioned anything about lava? Tell me where champion?

Would you have taken the time to make a little research before jumping to your keyboard to spread your immensely impressive intelligence to us, you could have read that this volcano eruptions are known to trigger large earthquakes. The largest most recent eruption, in January 1914 had very large pre-eruption earthquakes.

Anything else Einstein?

As I've said before, if Sakurajima (or Kirishima, for that matter) ever erupts violently enough to threaten Sendai, the nuclear power plant would be the least of our worries. (I live just up the road.)

@matthew

Well given that

1) As I mentioned, pre-eruption earthquakes are known to be potentially very large with this volcano.

2) An assessment proved that with big quakes which have taken place in "close proximity" to three nuclear power plants in Japan from 2005 to 2007, in each case, the ground motion (peak ground acceleration) caused by the quake was stronger than that for which the plants had been designed.

Who is fear mongering again?

You have to admit, daito_hak said nothing about lava. An active volcano located 50km from an active nuclear power plant IS a concern - not because of the threat of lava, but because active volcanoes and higher-than-average earthquakes are EXTREMELY close bedfellows. The underground fault lines don't give a whit about how many mountain ranges are jutting above the surface.

Tonight's NHK news devoted 20 out of 30 minutes on the volcano. And yet they, and nobody, mentioned that there is a nuclear plant down the road. Interesting.

Reactors do have procedures in place for SCRAMing the reactors during earthquakes, and after 3/11 I'm sure they've all included more robust emergency power supplies to account for downed power lines. Therefore while the concern is valid, the fear of a meltdown might be less than valid. I guess it would depend on what the power companies have done in the almost five years since 3/11 to ensure cooling of the cores are not interrupted during a power outage.

Earthquakes and volcanoes work on entirely different mechanisms. Furthermore, earthquake energy is centered onthe rupturing fault, and anybody with any knowledge of Kyushu geology knows faults here generally run southwest -northeast - so far from Sendai that, again, any quake sufficiently large to cause damage would level the entire region. http://tankyu.hatenablog.com/entry/2015/10/03/satsuma

You have got to love Japanese scientists. Utterly rational. All of the worlds media hyperventilating, wanting something that will get peoples pulses racing and they get this:

“I don’t think there will be any serious impact from the explosion,” Ishihara said. “But of course we must keep monitoring the volcanic activity.”

science; where truth and cool heads prevail

daito_hak: An assessment proved that with big quakes which have taken place in "close proximity" to three nuclear power plants in Japan from 2005 to 2007, in each case, the ground motion (peak ground acceleration) caused by the quake was stronger than that for which the plants had been designed.

And it's hard to believe they would have upgraded the safety of the plants enough, even post-Fukushima. How do you upgrade a plant to safely and passively disperse the core in the event of flood or earthquake and/or power loss, without replacing the core systems?

After all, TEPCO didn't suffer any pain from the disaster. The government bailed them out. They're probably going to much more money administering a 100-year Fukushima recovery than they would have selling power from the plant. That's how big government-service companies make their piles, by stretching out contracts with the government. If the contract is completed, then they have to compete for a new one, what's so fun about that?

If they can wangle another bailout for another failed nuclear plant, why wouldn't they? As long is it's not near Tokyo, right? And Sendai's way they hell away from Tokyo, right?

The largest most recent eruption, in January 1914 had very large pre-eruption earthquakes.

But probably no larger than other earthquakes that are anticipated in the area. I don't think the proximity of Sakurajima is the highest risk facing the Sendai nuclear plant. I agree with Fadamor's view that earthquakes are a valid concern. At Fukushima, the earthquake was not the accepted cause of the disaster, but the subsequent tsunami (there are opinions that differ about this). To date, the biggest real test of modern buildings' earthquake resistance in Japan has been the 1995 Hanshin earthquake. Most modern structures stood up well. Nuclear plants are built to at least the standards of any building in the Hanshin area.

[lighten up time - it's Friday] I once worked with some engineers from Chugoku Electric's nuclear plant in Shimane. They explained how it could resist earthquakes, plane crashes, etc. One guy asked if it could resist a missile attack from North Korea. Another answered that Shimane would never be the target. Such missiles would be aimed at Tokyo. A third wondered about the risk of a North Korean missile aimed at Tokyo but hitting Shimane instead. That spurred everyone to get out their calculators. (I love engineers.)

The Daichi plant design is relatively old. Newer designs such as the Advanced Boiling Water Reactors could suffer a failure of all outside power and the safety systems in the reactor would still prevent the core from being uncovered. They're only starting to build these types around the world, so the relative safety imparted by them isn't going to be obtained for years to come.

with over 200 such volcanoes across Japan, it's silly that they went with and continue to support nuclear.

Still scratching my head why Japan of all countries is not the leading geothermal energy producer. China has the greatest amount of resource but lacks the technology. Japan is sitting on a goldmine of work if they could produce the experts in the field.

hey let's restart the Sendai nuclear power plant!

It seems to me, that the positive that a nuke plant offers is immediately wipe out when there is a failure. The lives lost, the contamination of the surrounding areas never justify the savings in energy that was created by the nukes. And then we have yet to touch on that we do with the waste. Nope, nuclear energy is a very negative road to travel. Geothermal energy, wind and sun.

Laguna, you'd have thought a PHD with geophysics would know that but I guess he'd more focused on facts such as 'very big'.

@Davenetcat

Japan's easily accessible geothermal resources are estimated at around 1GW - that's the output of one NPP. There is more, maybe 20GW - but it's very deep and so hard to get at.

@star-viking

Although residential geothermal installations are less than 5m in non geothermal countries? You don't have to go down far for per building use. The extra geothermal in Japan is just a bonus for other uses. Also hydrothermal potential as well given the island and all the major cities on coasts.

Tonight's NHK news devoted 20 out of 30 minutes on the volcano. And yet they, and nobody, mentioned that there is a nuclear plant down the road. Interesting.

Well. I'd like to think it's because they only talk about those in immediate danger and those in secondary danger.

Ad opposed to a nuclear plant which is under no danger whatsoever. Unless you expect the lava to go up and down a couple of mountains? Or any pyroclastic flow to create a tsunami that would have to dog leg back on itself. In other words no respectable person would ever talk about something which simply couldn't happen. But hey that's apparently interesting

Heda_Madness: Ad opposed to a nuclear plant which is under no danger whatsoever. Unless you expect the lava to go up and down a couple of mountains? Or any pyroclastic flow to create a tsunami that would have to dog leg back on itself. In other words no respectable person would ever talk about something which simply couldn't happen. But hey that's apparently interesting

https://en.wikipedia.org/wiki/List_of_historical_tsunamis

Around 1600 BC, a tsunami caused by the eruption of Thira (also known as Santorini) destroyed Minoan civilization on Crete and related cultures in the Cyclades and in areas facing the eruption on the Greek mainland such as the Argolid.

http://www.distancefromto.net/between/Argos/Santorini

Distance between Argos and Santorini is 279.15 km. This distance is equal to 173.45 miles ...

http://www.distancefromto.net/?distance=sakurajima&distance=satsumasendai&distancemode[]=air

Sakurajima to Satsumasendia: 41.58 km, 25.84 miles

"The eruption did not affect the operation of the closest nuclear reactors, sitting some 50 kilometres (31 miles) from the mountain, media reports quoted operator Kyushu Electric as saying."

"Sakurajima's volcanic activity could increase," a weather agency official told a press briefing held shortly after the eruption."

"What I worry is what will happen next."

OUTSTANDING QUESTION!!

ref: http://news.yahoo.com/volcano-southern-japan-erupts-103336288.html

@sf2k,

Geothermal heating is very different from geothermal power: in the latter, the power actually comes from the sun, heating the immediate subsurface layers. Scientists and engineers don't actually call it geothermal heating for that reason, ground- source heat pump is one of the terms they use.

Lots of info here: https://en.m.wikipedia.org/wiki/Geothermal_heat_pump

Turbostat.. yes in areas facing the eruption. As opposed to areas in the opposite direction to the eruption that would require the tsunami to come out of a narrow bay turn right travel north and then turn right again. The water would spew out of the bay in completely the opposite direction.

Check the map.

@heda, turbotsat

Additionally, for a tsunami to occur, something has to dispace the water, and the water has to be able to freely move between the origin and any point that will be hit.

The Minoan tsunami is thought to have been initiated by the collapse of the volcanic caldera at Santorini. This directly displaced water in the Med, causing a very large tsunami.

In the case of Sakurajima, such an event would displace water in the bay, leading to massive waves in the bay, but nothing comparable outside.

It's odd that foreign news agencies are making a strong point that this eruption is only 50 kilometres away from a nuclear power plant. However, there is no mention of it what-so-ever in the Japanese news.

The distance around the peninsula from the volcano to the nuclear plant looks to be less than half the distance from Santorini to Argos. The Argolid civilization was destroyed.

The 2004 tsunami killed 35,000 in Sri Lanka, 1700 km / 1000 miles from the earthquake's epicenter, including 1700 riding a train on the opposite side of the island from the earthquake.

A short clip with simulations of the tsunami damage from the Minoan Eruption and the Krakatoa Eruption:

https://www.youtube.com/watch?v=oMe55hfSSgU

Turbostat.

Just look at the map. Your link shows an island in open water where the wave went in all directions. That's not going to happen in Sakurajima. Unless the waves go over the mountains.

And then we look at Sakurajima where there is a narrow inlet into open water. And you're expecting that a tsunami, with the power your suggesting will not go straight out of that inlet. But will actually come out of the water and go back on itself.

You're basically suggesting that modern is incorrect. And that a powerful volume of water will not go straight, it will not take the simplest route.

It's akin to suggesting that when someone project vomits their ears are most at risk. When you knock a glass of water down, which way does the water go? Does it double back on itself?

I'm more in danger from a tsunami caused by Sakurajima in New Zealand than the Sendai nuclear power plant is.

It's only around 50 miles from the outlet of the bay around the coast to the nuclear plant. And there's a large island offshore from the plant that can reflect a tsunami back onto it.

Tsunamis are not line of sight from the epicenter of what caused them. They go around things. That's evident from damage maps of the Indonesian tsunami and of the video I linked of simulations of the Minoan Eruption and the Krakatoa Eruption. It's only about 4 minutes long. Those events caused severe damage and deaths 100s of miles to 1000 miles from their epicenters, and the tsunamis went around islands, they didn't just stop and wash back.

The reason that it's only 50km around the coast is precisely the reason that it won't be affected. It will leave the bay at a tremendous rate and will not go back on itself. Something to with fluid dynamics. But spill that glass of water and tell me if the base of the glass gets wet. And if there's an eruption of krakatoa magnitude the nuclear power plant is the least if your concerns.

It doesn't have to be the magnitude of Krakatoa or Santorini. It just has to be enough for the surge out of the bay (where it will be near peak height) to wash back up the coast, reflect off the island opposite the plant, and flood the plant itself.

The 1958 tsunami due to an earthquake and landslide in a bay in Alaska knocked down trees 524 meters up (1,720 feet). Sendai NPP can withstand a tsunami of only 13-15m. You can see from the simulation video that tsunamis can go around corners.

Those trees in Alaska, were they in the bay or out the bay? Were they out the bay and round the corner.

What you're saying goes against everything that science says. You know that water doesn't react like a ball hitting a pool cushion don't you? You know that when it leaves the bay it will disperse into a wide area not a single narrow one?

And you also know that the 1958 earthquake wasn't caused by a volcano don't you?

your simulation video is irrelevant to sakurajima because of the geography. You're trying to compare an apple with a sheep.

Just because you think it will happen doesn't make it so. But if it really can happen then write the book explaining the science behind it. You'll probably win a Nobel prize for it.

The Alaskan tsunami was generated from a landslide, like the landslide from the volcano Mt. Unzen in the 1792 tsunami that killed 10,000 (with another 5,000 killed by the landslide itself).

It's not at all irrelevant. Large volcanic events have far-ranging effects. The water will disperse, but will it disperse enough? A 500-m wave from a Sakurajima collapse couldn't be 20m high by the time it made it out the narrow bay and back up the other side of the peninsula?

https://en.wikipedia.org/wiki/1792_Unzen_earthquake_and_tsunami

It is not known to this day whether the collapse occurred as a result of an eruption of the dome or as a result of the earthquakes. The tsunami struck Higo Province on the other side of Ariake Bay before bouncing back and hitting Shimabara again. Out of an estimated total of 15,000 fatalities, around 5,000 are thought to have been killed by the landslide, around 5,000 by the tsunami across the bay in Higo Province, and a further 5,000 by the tsunami returning to strike Shimabara. The waves reached a height of 33–66 ft (10–20 m), classing this tsunami as a small megatsunami. At the Osaki-bana point Futsu town, the waves locally grew to a height of 187 ft (57m) due to the effect of sea bottom topography.

Again you're ignoring geography. A tsunami within a bay will keep the power within the bay. It went back across the bay because once it hit Lanz it had nowhere to go. A tsunami in open water that hits an island has plenty of areas to go. Returning whence it came being the most resistant.

When a large tsunamI leaves the bay it will leave powerfully through the narrow channel. Its not going to turn right and right again.

It will go out like an inverted funnel in a V.

What happens in the bay is irrelevant to Sendai but hey I'm clearly wasting my time. You want there to be a possibility that Sendai is under threat. Despite all we know about science telling us otherwise.

It's not going to head straight out of the bay like a laser or a pencil, either. It'll fan out when it leaves the bay. Evidently you ignored the video, the maps of other events, the distances and wave heights mentioned.

I watched the video. But it's completely different geography so irrelevant. The maps of the other events didn't show a tsunami coming out of a narrow bay and then immediately turning back on itself.

The wave heights of the other events happened in a bay. Not where Sendai nuclear reactor is and so is irrelevant. The reactor is very close which is why it will be protected.

You accuse me of ignoring things.

Your ignoring basic physics and basic science simply because your determined that it is dangerous

And there's the fact that the Sendai plant has tsunami countermeasures too...

The Sendai plant has been reported to be vulnerable to tsunamis above 13m-15m in height, by their own reckoning. The simulation in the video and recent and past events show that large tsunamis can fan out around and behind islands and peninsulas, even 1000 miles from a generating event. There are islands to the south and southeast of the mouth of the bay, and another island offshore from the nuclear plant, that a tsunami could reflect off. A landslide event in a bay in Alaska generated a tsunami that knocked trees down at an altitude of 524 m above the bay.

Tsunami energy fans out. It is not like light from your flashlight, that heads on relatively straight.

Simulation of a fraction of the 2011 Tohoku tsunami fanning out in San Francisco Bay after passing through the Golden Gate:

https://youtu.be/tlIqfkkRZRQ?t=181

turbotsat,

That's a very interesting video. I like the bit at the 1:37 mark:

"Direct and reflected waves try to squeeze though the mile-wide Golden Gate"

And the one at 1:53:

"Those waves that get through immediately 'fan out' into San Francisco Bay"

And at 2:02:

"This squeezing and fanning reduces the wave size considerably"

And 2:09:

"The original five meter tsunami is not much more than one meter tall as it reaches the islands and shores of the Bay"

Now that is a tsunami arriving at a bay, but the squeezing and fanning, as the video demonstrates reduces the wave size.

So, with your own link, we see that wave sizes will be reduced. Refection off islands will also reduce wave size.

As for your reference to the Alaskan tsunami - yes, very large waves in the bay - nothing obvious outside the bay. Even with the large initial wave - 2 out of 3 boats in the bay managed to survive - and remained in the bay.

I didn't say they wouldn't be reduced. The question is would a large tsunami be reduced enough after fanning and reflection? Someday maybe a simulation will pop up on youtube and we can find out.

Re the video, as a I mentioned, a small fraction of the energy that fanned out from the epicenter crossed the Pacific, entered the bay through a small 1-mile-wide entrance and fanned out again from there.

The volume of collapsed material at Lituya Bay was 30M m^3, or 0.03 km^3. The volume of the 1792 landslide at the Mt. Unzen volcano was much larger at 0.5 km^3, about 16 times larger. The Santorini eruption ejected "an estimated DRE in excess of 60 km^3 (14 cu mi)", and "the volume of ejecta was approximately 100 km3 (24 cu mi)". (DRE = Dense Rock Equivalent.)

And with the Santorini volcanic event, the wave managed to cross 279.15 km / 173.45 miles to Greece and wipe out the Argolid civilization, even though the energy fanned out to a much greater degree than the Lituya Bay event.

Re the boats at Lituya Bay, one of the boats was swept out of the bay, over the spit at the mouth of the bay. The spit also likely blocked some of the energy of the wave from exiting the bay. One of the boats 'was anchored near the mouth of the bay' and sank with all on board. One managed to stay at anchor. But these were fishing boats operating on an unprotected coastline and some of them may have been ocean-capable, as you can see from the map the bay is not protected from the ocean except for the spit.

http://geology.com/records/biggest-tsunami.shtml

A third boat was in Lituya Bay at the time of the Tsunami. It was anchored near the mouth of the bay and was sunk by the big wave. There are no known survivors from this boat and it was believed that there were two people on board.

You're constantly missing the point. Every single example you have given is ahead of the source. You haven't produced a single example of a tsunami causing damage behind itself. In this case it would need to turn right, right again and right again to be able to cause the damage you believe would happen.

Do you have any examples of a tsunami going south west and then north

Within a very short distance. I'm guessing you haven't. And there's a very simple reason for that.

In the video posted previously, at timestamp 1:54, flooding is seen around corners from the eruption, to the northeast of it and to the northwest, in the simulation>

https://youtu.be/oMe55hfSSgU?t=114

Same eruption and video, different map and timestamp, "Mapped Inundation", flooding is seen through and to the east of the small strait to the south, including flooding in inlets along that coast to the east, as you say (but with different directions) an example of a tsunami going south, east, then north. The inlet on the opposite side of the island to the southwest was also flooded, to 13 m.

https://youtu.be/oMe55hfSSgU?t=118

The strait is about 80 km south of Krakatoa, so the flooded zones past the strait would have been farther.

https://www.google.com/maps/place/Krakatoa,+Anak+Krakatau+Island,+Pulau,+South+Lampung+Regency,+Indonesia/@-6.1021157,105.9036392,9z/data=!4m2!3m1!1s0x2e415e18b8f2e3ff:0x9e495f8e33b912dc

And again you are totally ignoring the geography and the fact it's coming out of a bay...but hey of you want to keep comparing apples with sheep that's fine.

Doesn't change facts

turbotsat

Re the video, as a I mentioned, a small fraction of the energy that fanned out from the epicenter crossed the Pacific, entered the bay through a small 1-mile-wide entrance and fanned out again from there.

No, the video states it represents a tsunami with the strength of 2011 hitting San Francisco - that's why it refers to a 5 metre tsunami hitting the coast. (Italics mine)

And with the Santorini volcanic event, the wave managed to cross 279.15 km / 173.45 miles to Greece and wipe out the Argolid civilization, even though the energy fanned out to a much greater degree than the Lituya Bay event.

But we are talking about a tsunami originating in a bay, with lots of the energy dispersed by hitting land and reflection.

Someday maybe a simulation will pop up on youtube and we can find out.

Or we can find scientific papers:

http://oce.oce.kagoshima-u.ac.jp/~taro/st_file/nstl.pdf

Refers to waves over ten meters in Kagoshima Bay caused by a landslide from Sakurajima. In the text it's actually 12 meters. Going out of the bay that will be considerably reduced, and even 12 meters would not threaten the Sendai Plant

Star-Viking: ... San Francisco .... http://oce.oce.kagoshima-u.ac.jp/~taro/st_file/nstl.pdf Refers to waves over ten meters in Kagoshima Bay caused by a landslide from Sakurajima. In the text it's actually 12 meters. Going out of the bay that will be considerably reduced, and even 12 meters would not threaten the Sendai Plant

Re San Francisco, OK, the simulation was not of the Tohoku earthquake's epicenter.

Re the link you posted, it appears to be a simulation, with the authors choosing the landslide mass. If the peak wave height is 12m, who would expect it to be 13m-15m around the NPP?

But if the peak wave height is 250m (Santorini), 250m (Valont Dam 1963), 260 m (Mt. St. Helens volcano 1980), or 524m (Lituya Bay 1958), how does that change the outcome?

That 524 metre wave in Lituya Bay, once it left the bay what happened to it? Did it turn right,right and right again? Was it still 524 metres high?

@Heda_Madness

Scroll back up ...

turbotsat: ... The volume of collapsed material at Lituya Bay was ... 0.03 km^3. The volume of the 1792 landslide at the Mt. Unzen volcano was much larger at 0.5 km^3, about 16 times larger. The Santorini eruption ejected "an estimated DRE in excess of 60 km^3 (14 cu mi)", and "the volume of ejecta was approximately 100 km3 (24 cu mi)". (DRE = Dense Rock Equivalent.)

So the answer to the question is no. It didn't come out of the bay turn right, right and right again.

Heda_Madness: So the answer to the question is no. It didn't come out of the bay turn right, right and right again.

The answer is yes. At the selected timestamp in the Lituya Bay simulation video below, the wave is seen to have turned right, right, and right again, back along the coast.

And that's with a little fraction of the landmass volume of the volcanic events, as listed above. The Lituya Bay collapsed material volume had 1/17th the volume of the Mt. Unzen landslide and 1/2000th the volume of the Santorini event.

https://youtu.be/B1axr5YGRwQ?t=224

Nope. What it did was wash over the low lying land and work it's way round.

If you looked at the topography of the region you will see that won't happen. And that's obviously ignoring the fact that a large chunk of land won't fall in to the ocean as earthquakes in that region or volcanic by nature.

But look at the maps... look at where the water will go and explain how sendai nuclear power plant is threatened by sakurajima.