Lava outbreak on Hawaii island
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Join Date: Apr 2007
Location: Hawaii
Posts: 121
India - thanks for your opinion on my question - I was thinking something similar but hadn't considered degassing. I did ask local folk what they think (not scientists I might add) and was told fluids do move uphill, not least because they have a working shower upstairs. I think they missed the point.
Anyway, I missed yesterday's update although I'm not sure a video was posted, but the latest is below. The eruption seems to be a little more vigorous but still contained well within the caldera.
India - about the lava island. My understanding is it formed immediately, i.e., as the water lake boiled away. I wonder if it's more like pumice than an iceberg? Of course, I have no idea how much normal pumice remains below the surface. All I know is it floats!
Anyway, I missed yesterday's update although I'm not sure a video was posted, but the latest is below. The eruption seems to be a little more vigorous but still contained well within the caldera.
India - about the lava island. My understanding is it formed immediately, i.e., as the water lake boiled away. I wonder if it's more like pumice than an iceberg? Of course, I have no idea how much normal pumice remains below the surface. All I know is it floats!
Join Date: Jun 2002
Location: CYWH (Victoria)
Posts: 5,518
That is a particularly informative video.
Pumice has a density of about 0.25 gm/cc and magma is ~2.6 gm/cc. The fraction of the island underwater is proportional to the density ratio, so if the island is a pumice raft, only 10% would be under the surface, that is 2' for a 20' high island. For comparison, pumice floating in the sea would have roughly 25% of its mass underwater.
Pumice has a density of about 0.25 gm/cc and magma is ~2.6 gm/cc. The fraction of the island underwater is proportional to the density ratio, so if the island is a pumice raft, only 10% would be under the surface, that is 2' for a 20' high island. For comparison, pumice floating in the sea would have roughly 25% of its mass underwater.
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Join Date: Apr 2007
Location: Hawaii
Posts: 121
No video update today I'm afraid. The latest text-based updates are available here:
https://www.usgs.gov/volcanoes/kilauea/volcano-updates
https://www.usgs.gov/volcanoes/kilauea/volcano-updates
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Join Date: Apr 2007
Location: Hawaii
Posts: 121
Nothing new to report today. The lava lake continues to rise slowly which is no surprise given it's essentially a cone that it's filling, so if the rate of lava input remains constant, the lake will rise more slowly over time. The island in the middle of the lake continues to make chess-like moves and everyone on the island is safe right now other than the vog issues on the western side of the island. But locals have learned to live with that over the last few decades. It was nice to get a 1.5-year break from the vog, but the pandemic means many are staying at home anyway - apart from the tourists of course although there are far fewer than normal.
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Join Date: Apr 2007
Location: Hawaii
Posts: 121
New video update today. There have been changes but they are all within the caldera and there are no signs at the moment that the eruption threatens anyone. I think it's relatively safe to say this is how Kilauea has behaved for thousands of years, but this is the first time we've had the chance to document it with modern instruments, and obviously, scientists with a much better understanding of the system than any time in history.
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Join Date: Apr 2007
Location: Hawaii
Posts: 121
Originally Posted by jolihokistix
Thanks for the updates, will watch these later when I get hme.
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Join Date: Apr 2007
Location: Hawaii
Posts: 121
No video update today but the Hawaii Volcano observatory gives daily test updates:
https://www.usgs.gov/volcanoes/kilauea/volcano-updates
I have trouble picturing the amount of lava in the caldera. Today's HVO update says:
"The lava lake was 194 m (636 ft) deep Friday afternoon (Jan. 8) and had a volume of more than 27 million cubic meters (36 million cubic yards). The most recent thermal map (Jan. 7) provided the perched lake dimensions as 760 by 470 m (830 by 540 yds) for a total area of 28 ha (69 acres)."
I can't picture 27 million cubic meters, it's like trying to imagine how many stars there are in the Galaxy. In the past, I've seen comparisons to how many Olympic-sized swimming pools this is, but I've never seen such a pool and even then it's hard to picture exactly how large the lava lake is. I wonder if it's time to use another measure; compare it to something large. Opinions welcome and I can pass them on if they're reasonable and sensible.
This isn't sensible, but I was thinking of the number of Embassy Suites hotels would fit into the lake. Most of those hotels are roughly the same size, are quite large so would be easier to picture. I suspect most of you travel a lot and might understand why I suggest this. I don't think it will fly, but other suggestions are welcome!
https://www.usgs.gov/volcanoes/kilauea/volcano-updates
I have trouble picturing the amount of lava in the caldera. Today's HVO update says:
"The lava lake was 194 m (636 ft) deep Friday afternoon (Jan. 8) and had a volume of more than 27 million cubic meters (36 million cubic yards). The most recent thermal map (Jan. 7) provided the perched lake dimensions as 760 by 470 m (830 by 540 yds) for a total area of 28 ha (69 acres)."
I can't picture 27 million cubic meters, it's like trying to imagine how many stars there are in the Galaxy. In the past, I've seen comparisons to how many Olympic-sized swimming pools this is, but I've never seen such a pool and even then it's hard to picture exactly how large the lava lake is. I wonder if it's time to use another measure; compare it to something large. Opinions welcome and I can pass them on if they're reasonable and sensible.
This isn't sensible, but I was thinking of the number of Embassy Suites hotels would fit into the lake. Most of those hotels are roughly the same size, are quite large so would be easier to picture. I suspect most of you travel a lot and might understand why I suggest this. I don't think it will fly, but other suggestions are welcome!
Join Date: Jun 2002
Location: CYWH (Victoria)
Posts: 5,518
Hokulea,
I’ve worked out a couple of examples to help with the visualization. I know the US still uses Imperial units, but the USGS has converted and you’re a scientist, so I’ll stick to SI units.
1. Just for fun. 2.7 x 10^7 cubic metres of lava, spread uniformly over the whole of the Big Island, would create a lake 2.6 mm deep!
2. More practical. It’s roughly equivalent to the volume of 35 Empire State Buildings.
I’ve worked out a couple of examples to help with the visualization. I know the US still uses Imperial units, but the USGS has converted and you’re a scientist, so I’ll stick to SI units.
1. Just for fun. 2.7 x 10^7 cubic metres of lava, spread uniformly over the whole of the Big Island, would create a lake 2.6 mm deep!
2. More practical. It’s roughly equivalent to the volume of 35 Empire State Buildings.
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Join Date: Apr 2007
Location: Hawaii
Posts: 121
Thanks for that, India! The Empire State Building comparison works well as I've visited that and know how big and high it is. As to the comparison to covering the Big Island, for people who may not be familiar with the island, it is roughly the same size as Wales.
Incidentally, as a six or seven year old I was taught both the imperial and metric system as it was the time UK was switching to decimalization. I've always been comfortable working with both and can usually convert in my head to my preferred unit, so don't worry about sticking to SI units if you prefer not to! I think it's a bit like kids learning to speak different languages if they're taught early enough.
Incidentally, as a six or seven year old I was taught both the imperial and metric system as it was the time UK was switching to decimalization. I've always been comfortable working with both and can usually convert in my head to my preferred unit, so don't worry about sticking to SI units if you prefer not to! I think it's a bit like kids learning to speak different languages if they're taught early enough.
