[rockdoc123]

The actual mechanisms are still debated somewhat but most believe circulation in the mantle coupled with density spreading of new oceanic crust from the higher ridges towards the subduction zones is the main culprit. The subducted slab is melted and contributes to volcanoes through uprising magma, the majority being assimilated into the mantle and redistributed at the ocean ridges.

[ROCKMAN]

Donlan - All good questions. But I doubt those dynamics can be measured in the span of a human lifetime. And worse: I doubt anyone is making much effort to measure "the big picture".

[dohboi]

Ambae, one of the islands of the Vanuatu archipelago, has a volcano- Monaro- that has always been active but is now destroying the habitat.

https://www.theguardian.com/world/2018/ ... t-on-ambae

A landslide and flash flood on the Vanuatu island of Ambae is complicating evacuation efforts, with as many as 800 people now sheltering in emergency relief centres.

Ambae Island is home to 11,000 people, and for the second time in six months Manaro volcano on top of Mount Lombenben has started rumbling, spewing torrents of ash, gas and rocks from its crater. The debris is causing breathing and health problems, and threatening livelihoods by burying vegetable plots and crops.

The government has declared a three-month state of emergency while it works with non-governmental organisations to safely evacuate the island and secure new homes for displaced islanders who may never be able to return.

Acting prime minister Jean Pierre Nirua said Vanuatu was the most vulnerable country in the world to natural disasters, and was currently stretched by responding to the clean-up of last month’s cyclone Hola and the unfolding Ambae emergency.

According to the Vanuatu meteorology and geohazards department the volcano remains at level three, with a danger zone surrounding the cone of three kilometres.

Due to eruption activity the cone of the volcano had widened, resulting in ash fall, gas, and acid rain, as well as a heightened risk of landslides and flash floods.

[Plantagenet]

Small eruptions continuing on Sentaru Volcano here on Java

Cheers

[dohboi]

https://www.cnn.com/2018/05/04/us/kilau ... index.html

Hawaii's Kilauea volcano erupts, prompting mandatory evacuations

(Video includes lava spewing out of a road in a suburban development.)

[Plantagenet]

The last eruption in this area east of Kiluea was in the 1960s---and it went on for months. All the current houses in this area have been built since this time. Whoever was in charge of residential zoning should be prosecuted --- it was very irresponsible to allow houses to be built in this area.

It will be interesting to see if this current eruption is a repeat of the 1960s eruption, or if Kiluea is doing something new.

Cheers!


Its crazy to allow houses to be built anywhere along the east rift zone of Kiluea---the whole area is at extreme risk for lava flows

[dohboi]

Sooo, you're for strong government regulation and against people making money?

[Newfie]

Being down here in the Carribean I’ve gotten a whole new appreciation of volcanoes. This coming week we will be passing “Kick em Jenny” an underwater volcano, an island in the making. A couple of months ago it was active and the exclusion zone was increased to about 5 miles. But it’s gone quiet again so the exclusion zone is back down to about a half mile. Lava won’t leap out and grab you, but gasses will reduce the water density to the point where your ship will sink.

Having fun.

[Tanada]

The last eruption in this area east of Kiluea was in the 1960s---and it went on for months. All the current houses in this area have been built since this time. Whoever was in charge of residential zoning should be prosecuted --- it was very irresponsible to allow houses to be built in this area.

It will be interesting to see if this current eruption is a repeat of the 1960s eruption, or if Kiluea is doing something new.

Cheers!


Its crazy to allow houses to be built anywhere along the east rift zone of Kiluea---the whole area is at extreme risk for lava flows

I disagree completely. I think people wanting to build in the area should be required to sign a declaration of understanding to show they know the risks and any time a new person buys or leases property there they should also have to sign said declaration. Other than that I think adults have the right to do stupid stuff, otherwise you would need 24/7 security following everyone everywhere to keep them from getting boo-boo's and then you would need more security to watch over the first security and so on ad infinitum. You either have to accept people are adults, or you have to treat them as infants, there is no middle ground.

[Newfie]

Tanada,
That’s a tough choice. If you accept them as infants then you are having them followed by infants. On the other hand if you accept them as adults you assume they will not do stupid things and hurt others, unlikely.

If we treat all folks as adults then we need to accept they will off themselves on a regular basis and if they off someone else then they have proven to not be adult and need to be removed themselves.

I’m OK with that, but I doubt it will get popular approval.

[Plantagenet]

Sooo, you're for strong government regulation and against people making money?

Yes, I'm against people building homes in areas where volcanic eruptions occur frequently. This doesn't preclude the use of the land for other purposes that can make money, such as agriculture.

Part of my scientific work has involved making scientific studies of volcanic hazards, seismic hazards, flood hazards, etc.

Scientists are pretty good at delineating areas on the ground that are at clear risk from natural hazards, and at predicting the statistical likelihood of a recurrence of the natural hazard. This information is typically compiled in "hazard zone maps" that are made available to the public and are officially transmitted to local government officials.

However, its not up to the scientists to set zoning laws----its up to local governments. IMHO homes, hospitals, schools etc. shouldn't be built in areas that have a significant likelihood of being destroyed every 50-100 years of so by natural hazards but I understand that some property rights extremists like yourself will put profits over people and will fight any zoning restrictions.


lava hazard map for the island of Hawaii

Cheers!

[Newfie]

We visited Monserrat where the town was built on an old ash flow, it was the level ground. They evacuated the southern half of the island. The North half is very steep, they had to build much new housing there. There is nonreal town anymore, just folks living here and there.

Then we went to St Pierre on Martinique. May 8, 1902 pyroclastic explosion took out entire town of 30,000. Then in August that year a second explosion killed another 3-4,000, one additional town and some relief workers in the old town. Looking at the geography you would think the town was protected, it wasn’t. But the sides of the volcano are full of agricultural fields and the area is being built back up. St Pierre is now about 5,000 but there are many more in newer towns and scattered about the general area.

[Plantagenet]

We visited Monserrat where the town was built on an old ash flow, it was the level ground. They evacuated the southern half of the island. The North half is very steep, they had to build much new housing there. There is nonreal town anymore, just folks living here and there.

Thats very interesting.

I went to Montserrat for a couple of weeks as a consultant during the beginning of the eruption crisis in 1995, and I arrived just after a pyroclastic flow killed a number of local people who were going back into the red zone to tend crops. There was a posh British ex-pat community living in cliffside villas along the west coast, and they put me up in a nice cliffside villa with a grand ocean view. At that time they had already mostly evacuated the town, although the British volcano response team was working out of a funky old hotel on the north edge of the town near the beach. The town had a well known recording studio that reggae artists liked to use, but the town was largely shut down although just lightly covered by ash when I was there. Now the buildings are pretty much buried by mudflows, ash and PFs I hear. The locals had mostly already been relocated to big hot stuffy brown canvas british issued military tents in a couple of sites on the north side when I was there, with most looking at being evacuated to England.


Sounds like the tents are gone, but things still aren't back to normal on what is left of Montserrat.


Cheers!

[dohboi]

"property rights extremists like yourself "

moi??

I don't give a flying fig about property rights. Perhaps this was addressed to T?

I just found it interesting that, in this case, you accept that people should be told not to make money if that might end up hurting someone. This is the essence of the philosophy of an American liberal, and I hadn't pegged you for one of those.

Anyway, things seem to be getting worse:

https://www.cnn.com/us/live-news/hawaii ... -eruption/


A fifth volcanic vent has opened in Leilani Estates

Thousands without power after 6.9 quake

Earthquake triggers landslides along Hawaii's coast

[dohboi]

And now...Alaska:

https://www.cnn.com/2018/05/05/us/alask ... index.html

I wasn't even aware that Alaska had volcanoes! D'oh!

Makes sense, though, being in the 'ring of fire.'

[Newfie]

Plant,

Take this with a grain of salt, stuff I got from the old guy who showed us around the island. Let’s hope I’ve got the numbers straight.

Pre eruption there were about 12,000 in the island.
Now there are about 5,000 remaining. So 7,000 emigrated to the UK and elsewhere.

Wrong! 10,800 emigrated. If the 5,000 remaining only 1,200 are from Montserrat, the balance, 3,800, are immigrants from Haiti, DR, and Guyana, places even less fortunate than Montserrat. They come there to establish citizenship which takes 6 years and then enables them to move to the UK.

Or so I’ve been told. I don’t really know the truth but it sounds reasonable although one has to ask why the government would allow such a thing. I suppose there are reasons.

It does lead one to ask when they should just abandon the entire island, turn it into a nature park.

Newfoundland struggles with these decisions.

http://www.cbc.ca/news/canada/newfoundl ... -1.4560571

In follow up to the above the most recent vote was 100% in favor of resettlement.

[dohboi]

See the massive sinkhole — six stories deep, two football fields long — that opened underneath a New Zealand farm. A volcanologist says it may have been growing underground for up to 100 years before recent heavy rain opened it up.

https://cbsloc.al/2Idx4Tu
https://twitter.com/CBSLA/status/992496999458099200

(I'm pretty sure Saruman had something to do with this one! )

[Plantagenet]

And now...Alaska:

https://www.cnn.com/2018/05/05/us/alask ... index.html

I wasn't even aware that Alaska had volcanoes!

On average about one eruption per year occurs at one or other of the Aleutian Island Volcanoes. Mt. Cleveland is among the most active, but the island its on is uninhabited.


If a volcano erupts on an island that is so remote that no one hears it, does it make a sound?

Cheers!

[dohboi]

Thanks, P. And...no (but it does make noise! )

Meanwhile, further south:

Lava Flows and Sulfur Dioxide Threaten Leilani Estates on Kilauea

The new eruption far on the East Rift zone of Kilauea is continuing. The latest count has at least 10 fissure vents erupting ... on the east side of Leilani Estates and more cracks in the ground, some releasing copious sulfur dioxide gas.

The lava flows coming from the fissures vents that are intermittently erupting has destroyed at least 5 homes so far with more being threatened and has overrun a number of roads. The lava fountains from the active fissure vents have reached as high 70 meters (215 feet) — you can watch some of the impressive footage of the eruption below. All of the Leilani Estates subdivision has been evacuated with little idea when residents might be permitted back into their homes.

In some of the most stunning video, you can see a fissure erupting in the middle of an area of homes. These vents could be active for weeks-to-months, so many of these homes could be inundated with lava. This part of Hawaii is by no means wealthy, so the stakes are high for the people who live in Leilani Estates — many of which may not be able to just “pick up and leave”.

However, it is the sulfur dioxide gas that is the real danger to people, as the concentrations being emitted are high enough to kill someone — the sulfur dioxide combines with water in your lungs and throat to form sulfuric acid! The sulfur dioxide plume has been mapped from the Suomi-NPP satellite, spreading to the southwest of the eruption...

http://blogs.discovermagazine.com/rocky ... n-kilauea/
Maps and video at the link.

[ROCKMAN]

Some interesting facts: Kīlauea's eruptive history has been a long and active one; its name means "spewing" or "much spreading" in the Hawaiian language, referring to its frequent outpouring of lava. Lavas younger than 1,000 years cover 90 percent of the island's surface. Not unreasonable to expect every structure to be destroyed in some X hundred years. The elevation above sea level of the island doesn’t look that significant but: "It is the TALLEST mountain on earth. Measured from its base on the ocean floor, it rises over 33,000 ft, significantly greater than the elevation of Mount Everest above sea level. Amazing given it began growing only 350,000 to 400,000 years ago.