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Lava outbreak on Hawaii island

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Lava outbreak on Hawaii island

Old 12th May 2018, 09:55
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OK, so I do have a question for the geologists here although fully understand if it's not exactly your area of expertise.

Puna Geothermal Ventures (PGV) is a geothermal plant in lower Puna on the Big Island that supplies some of the energy to the island's electrical grid. Understandably, it closed down after the 6.9 mag earthquake last week and the threat of volcanic activity. The potentially flammable chemicals have been taken offsite (pentane) but the remaining wells have not been capped. These go as deep as six to eight thousand feet. The PGV site is right in the middle of the current eruptive activity and ground cracks have been observed on the property and on both east and west sides, so there is clearly magma moving underneath the property.

The concern is those wells not only might provide easy access for magma to reach the surface, but might also allow sulphuric acid gas to be emitted, in addition to the SO2 emissions that local residents are already experiencing.

So, after that background, how do you cap those wells? The current strategy seems to be to fill them with water, sometime soon, which most of us here find astonishing, but few of us are experts in this kind of thing.

For further background, this was an interview with Magno, Hawaii Island's head of civil defense and made most of us cringe and wonder if he is way out of his depth. However, the above is a genuine question. In the meantime, the source of information about civil defense's plans comes from this interview. The PGV stuff starts around the 8-minute mark. It concerned many of us that Magno had to be corrected by a USGS scientists about cracks at PGV and for much of the rest of the time just grinned and shrugged his shoulders.

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Old 12th May 2018, 10:58
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Apparently totally safe, and has happened previously. The narrow shaft and the magma viscosity means it only rises slowly, and the cooling effect of the water means it solidifies as it rises forming its own plug at the bottom the shaft.

Drilling to the mantle: Could it cause a volcanic eruption?

“......Even if engineers were to drill directly into a reservoir of molten magma, a volcanic eruption would be extremely unlikely. For one thing, drill holes are too narrow to transmit the explosive force of a volcanic eruption. (It’s the equivalent of piercing a champagne cork with a pin rather than removing the entire cork at once.) In addition, if the hole is only 30 centimeters wide—the diameter of the planned borehole in the mantle drilling project—the small amount of magma that could flow into the shaft would solidify long before reaching the surface. Engineers have accidentally penetrated magma reservoirs several times. In 2008, drillers struck magma in Hawaii while attempting to find a geothermal energy source. Scientists did the same thing in Iceland seven months later. The magma usually destroys the drilling rig, but it doesn’t trigger an eruption. Scientists are even about to drill into an active volcano near Naples, Italy.......”

from the Hawaii link above:

“.......This is not the first time drillers have encountered magma; the depth of the hit and the setting are, however, thought to be unique.

The exploratory well was being put down in the east of Hawaii's Big Island, through the basalt lava fields formed by Kilauea Volcano. The idea was to find steam from waters heated deep underground in fractured rock, to drive turbines on the surface to generate electricity. The company behind the project, Puna Geothermal Venture, has had a successful power operation in the area for 15 years.

But the drillers were shocked - not only to hit magma but to also hit such a big heat source at the relatively shallow depth of 2.5km. "It's hotter than hell; it's over a thousand degrees centigrade," said Professor Marsh.

Bill Teplow, a consulting geologist with US Geothermal Inc, who oversaw the drilling, stressed there was no risk of an explosion or of a volcanic eruption at the site. "It was easily controlled in the well bore because of the magma's highly viscous nature. It flowed up the well bore 5-10m but then the cool drilling fluid caused it to solidify and stop flowing," said Mr Teplow......”



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Old 12th May 2018, 11:10
  #63 (permalink)  
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Yes, I'm aware of that, but that was before the current activity. Magma is now at a much shallower depth underneath the closed PGV plant (i.e., they are not pumping fluids into the wells), hence the reason I was asking the geologists.

Last edited by Hokulea; 12th May 2018 at 11:24.
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Old 12th May 2018, 11:23
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I can understand your concern about the competence of your head of civil defense, having watched that video I'd have to say that he's either poor at presenting himself and his organisation on camera, or he's way out of his depth. I reckon it's the latter, based on his inability to accurately answer many of the questions. There must be loads of data available to him on things like sulphur dioxide levels etc, yet he doesn't seem to have been properly briefed before giving that interview at all.

I don't think I'd have a lot of confidence in an organisation headed up by someone like that; let's hope that things settle down and he isn't required to make any really important decisions.
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Old 12th May 2018, 11:34
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Thanks, VP959. I got a laugh today from someone here who said "That's Hawaii. Got lava, call California, get told to pee on it.".

Last edited by Hokulea; 12th May 2018 at 13:48.
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Old 12th May 2018, 16:56
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I agree with VP759. The interview with the civil defense head was embarrassing to listen to. I'm surprised he allowed himself to be "door-stepped" like that by the TV reporter.

Here is a summary of the operation of the Puna Geothermal plant:
DESCRIPTION: PGV is a geothermal energy conversion plant bringing steam and hot liquid up through underground wells. The hot liquid (brine) is not used for electricity at this time. The steam is directed to a turbine generator that produces electricity.

The exhaust steam from this turbine is used to vaporize (heat) an organic working fluid, which drives a second turbine, generating additional electricity. The condensed steam from the organic fluid heat exchanger is re-injected into the ground through reinjection wells along with the brine.
https://www.hawaiianelectric.com/cle...-venture-(pgv)

This process is known as Combined Cycle:



The "working fluid" is pentane, which has been removed from the site, as a sensible precaution. The production wells and the reinjection wells will have been shut-in using the valves in the well head. It is possible that there may be downhole valves in the production and injection tubing which can also be closed.

All jokes aside, the wells are already full of hot water and steam, so pumping cold water (probably dense brine) is not as stupid as it sounds. In an extreme case, like a blow-out while drilling, dense "drilling mud" is pumped into a well, to create a sufficient hydrostatic head in the well bore, to offset the pressure of the reservoir.

As ORAC pointed out, there is no chance that magma could flow to the surface in these wells. What is more likely, judging by the picture below, is that the fissures could extend through the area of the plant, in which case, the presence of the wells is irrelevant. The plant is in the bottom right:



I must admit I was surprised by the references to H2S. This is a common unwanted component of oil and natural gas operations and is difficult, expensive and dangerous to deal with. I had completely forgotten that volcanic gases can contain H2S.

SO2 is unpleasant and a health hazard, but H2S in sufficient concentrations will kill you:
500-700 ppm Staggering, collapse in 5 minutes. Serious damage to the eyes in 30 minutes. Death after 30-60 minutes.
700-1000 ppm Rapid unconsciousness, "knockdown" or immediate collapse within 1 to 2 breaths, breathing stops, death within minutes.
>1000 ppm Nearly instantaneous death
I doubt that these kind of concentrations would exist at any distance from a volcanic gas vent.

The really insidious characteristic of this gas is that at concentrations of over 100 ppm, you lose your sense of smell and so the "rotten egg" warning smell is gone. Very serious safety precautions are taken at gas wells and processing plants that deal with so-called "sour gas".

Last edited by India Four Two; 12th May 2018 at 17:14.
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Old 12th May 2018, 17:25
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It also plays merry hell with things like normal steel after a while

H2S is slightly heavier than air and has killed whole villages in places like Indonesia - there was a case a few years back when a volcanic vent went off at night and the villagers all ran down the valley to escape and ran straight into a wall of H2S..... lots dead

In 1998 I had the privilege of meeting the Russian Chief Drilling Engineer who drilled the world record Kola Crustal test well to over 40,000 ft in the early 1990's. He said that once the temperatures reached over 150C it became progressively harder and harder to make progress - the drill string etc just kept buckling and jamming

As for Hawaii - the eastern end of the main island is clearly now over the hot spot in the crust - they 'll probably finish up with a 4000m high volcano there as the island drifts slowly to the north and east as all the other islands have done.............
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Old 13th May 2018, 02:03
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Thank you, India Four Two. That was very helpful.
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Old 13th May 2018, 06:22
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Major portions of Hawai‘i Volcanoes National Park (which is basically Kīlauea) were closed when I was there two years ago in large part due to the H2S risk - and that was during the continuing 'low level' eruption. I see that they've now they've closed the whole park due the current, err, higher level eruption.
I seem to recall a claim that the volcanoes on the Big Island could be considered to be the tallest mountains on earth as they start several miles below sea level.
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Old 13th May 2018, 06:47
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the volcanoes on the Big Island could be considered to be the tallest mountains on earth as they start several miles below sea level.
The summit of Mauna Loa is about 31,000' above the abyssal plain - that's 2000' more than Everest.
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Old 13th May 2018, 06:52
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Right after the 2008 summit eruption, the drive around the summit caldera was closed due to concerns about gas, although I forget if it was SO2 or H2S that was the concern. It hasn't been re-opened since then as the eruption has been ongoing. It was the right decision based on safety grounds, but it was a shame as that drive is fascinating, especially where you get to the start of the western part of the rift as you actually see where part of the island is slowly splitting away.

Mauna Kea, which is currently dormant, is about 33,000 feet from its base on the ocean floor to the summit, so in that sense is the tallest mountain in the world.

Quick update: fissures 16 and 17 opened today (no. 17 an hour or so ago). These two are the easternmost fissures and indicate a migration of the fissure activity towards Kapoho and the ocean. If and when that happens, part of the island south of the rift will be cut off. Today, the Hawaii National Guard were flying helicopters overhead (from my perspective) in practice runs in case they are needed for evacuation purposes.

Latest map of activity: https://hawaiicountygis.maps.arcgis....5eb32761793078

Video of fissure no. 16:
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Old 13th May 2018, 10:56
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Years ago when I was on the volcano tour, the tour guide mentioned that the houses closest to the volcano were houses built by drug dealers and other undesirables. Any truth to that?
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Old 13th May 2018, 11:19
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No, there isn't.
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Old 13th May 2018, 12:23
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Thanks for the link Hokulea.............. really good
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Old 13th May 2018, 12:32
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This thread has been pretty educational. I had no idea just how curious the geology of Hawaii is. I'd not realised that the island chain is smack in the middle of a tectonic plate, not at the edge, where the majority of the world's volcanic activity seems to be. The "hot spot" that formed the Hawaii island chain has created a long line of islands and sea mounts that run all the way to Siberia, and show how that tectonic plate has moved over millions of years. Fascinating stuff, and I can understand now why the risk of a really catastrophic eruption seems pretty low.
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Old 13th May 2018, 12:54
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Yes, I've seen so much stuff about Hawaii and the "ring of fire" in mostly social media but occasionally mainstream media. Let's be clear, the ring of fire is real, but Hawaii is not in the ring, it's smack in the middle of a tectonic plate. Today I saw something in the Daily Mail that just had my head in my hands. I won't provide the link because I don't want to spread misinformation, but the headline claimed that the current Hawaii eruption might cause catastrophic eruptions in the Cascade area in the US. It's utter bollocks and not even supported by what's in the actual article, but there you go, it's the modern tabloid press I guess.

Getting sick and tired of earthquakes. I'm not in the danger zone (I live about 10-miles north of the current activity) and they've all been minor since the large one a week ago although the house gets shaken regularly, but really looking forward to an upcoming vacation away from here. That's if Kilauea doesn't blow its lid, then flights become an issue.
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Old 13th May 2018, 13:06
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Yes the volcanoes get older as you move NW - they gradually erode and become sea- mounts as they're not "re-charged " from the hot spot

There's a similar one in the Gulf of Benin IIRC

Sympathise Hokulea - but it comes with the territory I'm afraid - better a lot of small earthquakes than a couple of big ones
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Old 13th May 2018, 13:15
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Completely understand, Harry. I chose to live here and have to live with that decision. It's been a good one so far and will probably work out to be the best decision I ever made, but there's such a thing as island fever. Now it's earthquake fever!

PS. I should add that being a scientist that has had my own research being disrupted by this activity is crap, but being here seeing first-hand and seeing what the island is doing and what might happen soon more than makes up for it. It's a bit scary but utterly fascinating. In my mind, you can't beat that.

Last edited by Hokulea; 13th May 2018 at 13:29.
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Old 13th May 2018, 13:24
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Originally Posted by Heathrow Harry View Post
Yes the volcanoes get older as you move NW - they gradually erode and become sea- mounts as they're not "re-charged " from the hot spot
For those that are curious, this Google Earth image shows the "dog leg" line of movement of the tectonic plate as it has shifted over the hot spot. Hawaii is right at the bottom, and the line of sea mounts extending NW and then pretty much due N are quite easy to see:

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Old 13th May 2018, 16:06
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Devil Island Fever

I completely empathize with your "heebie jeebies", Holukea! I lived on an island for a decade, St. Simons Island, Georgia, which was less than five miles from the U.S. mainland. Though we did not suffer the twin threats of volcanic eruption and strong earthquakes, we did have to put up with "tourons" (tourist + moron) for seven months a year. There was also the occasional hurricane...

Might I presume from your vocational description that you might be affiliated with the W.M. Keck Observatory? If so, what sights you have seen! In one lifetime, you have been eyewitness to the creation of land through lava flows and the creation of the visible Universe through the Big Bang. Few can make that claim - you have my admiration and jealousy, but mostly my hope that you will stay safe and continue your valuable reportage.

- Ed
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