I'm Matt Patrick.
I work for Hawaiian Volcano Observatory.
And Tricia Nadeau is here, as well.
We'll be kinda going back and forth
talking about different aspects of the summit activity.
We're here basically just to give a summary
of what's been happening
and the recent changes over the past year.
This is a recent view from the western caldera rim
showing Halema'uma'u and the sections of the caldera floor
that dropped during 2018
and other levels of the caldera floor here.
And this water pond that's a new feature
over the past several months, since summer.
Just to give a basic overview of Kilauea Volcano,
this is probably review for most of you.
Kilauea is on the southeast portion of the Island of Hawaii,
and the summit caldera is a center
of much of the historic activity.
Kilauea has two rift zones, the Southwest Rift Zone,
which is not shown here, not labelled here, sorry.
The East Rift Zone, which extends out along here.
There's been a large amount of historic activity,
including a lot of recent activity,
including the Pu'u O'o eruption from 1983 to 2018,
and the big 2018 eruption
occurred on the lower flank of the volcano
on the lower East Rift Zone.
And of course, the lower East Rift Zone contributed to,
or was associated with,
the collapse of a portion of the caldera floor here.
This is a recent view of the summit.
Here we are at the Visitor Center,
and here's the caldera, a couple miles across.
We have this new scarp, this new cliff,
in the center of the caldera,
and that formed during the subsidence of this portion
of the caldera floor during 2018.
And we have Halema'uma'u
in the southwest portion of the caldera
that enlarged and it deepened during the 2018 activity.
Halema'uma'u is, we're gonna be talking a lot about it.
It's important to recognize that this is a sacred place.
The Park has a lot of great background
on the cultural context of the summit
and Halema'uma'u, in particular.
It's the home of Pele.
This is related to the fact that Halema'uma'u
has been a center,
has been a center of activity for many years.
There was a lava lake activity through much of the 1800s,
into the early 1900s.
Nearly continuous lava lake activity.
The lava lake activity at the summit in Halema'uma'u
was a big reason that HVO was founded in 1912.
The reason that it was started was to make direct,
close observations of continuous volcanic activity,
to try to better understand volcanic hazards
and to make better forecasts.
That lava lake activity from the 1800s,
basically a century of lava lake activities
from the 1800s into the early 1900s,
came to an abrupt end in 1924,
when there was explosive activity that widened the crater,
ended that 100 years of lava lake activity.
Through the rest of the 20th century,
there was still summit activity,
but it was sporadic and episodic,
usually short-lived days or weeks.
The last eruption of the 20th century was in 1982.
Then there was 25 years of eruptive pause at the summit.
Lava lake activity returned in 2008,
and that lava lake activity lasted for 10 years.
How many of you stood at Jaggar
and watched the lava lake here?
Most of you.
Many times, you could just see the glow
because the lake was a little bit too low
to see directly from Jaggar.
But there were numerous times, particularly in 2016,
when the lake was high enough,
that you could see it on many days.
This was a really spectacular phase of activity on Kilauea.
There are not many persistent lava lakes on Earth.
This was one that was very accessible.
It provided a lot of new insight into lava lake behavior.
That came to an abrupt end in 2018.
So, let's talk about the 2018 activity.
Basically tere was a large eruption,
lava flow eruption on the lower flank of the volcano,
on the lower East Rift Zone.
That eruption caused magma
to drain from the summit magma chamber.
That removed support from the roof of the chamber
and the floor of the caldera dropped,
portions of the caldera floor dropped,
causing enlargement of Halema'uma'u
and also subsidence of the broader area around Halema'uma'u.
That 2018 activity ended the long-lived Pu'u O'o eruption.
35 years of activity there ended very abruptly.
It also ended that 10-year-long lava lake
that we had at the summit.
There had been previous collapses at the summit,
a handful in the 1800s,
but the one that occurred in 2018 was the largest one
that we know of that's been recorded in the past 200 years.
Unfortunately, the lower East Rift Zone eruption
has the distinction of being the most destructive eruption
in Hawaii in the past 200 years.
Over 700 structures were destroyed.
This gives you an idea
of what the lower East Rift Zone eruption looked like.
This is the dominant vent, fissure eight.
You can get a sense, just from the size of this channel,
and the rate that lava was flowing through it,
that these were very high eruption rates.
Eruption rates 50 to 100 times greater
than what we observed during the previous years
of Pu'u O'o activity.
That high eruption rate was draining magma
from the summit magma chamber,
causing the floor of the caldera to drop.
This is a time-lapse camera that we had near Keanakakoʻi,
looking north, and showing the drop of this section.
This used to be flush with this,
and it dropped over 100 yards.
Other sections around Halema'uma'u dropped much more.
To give you a sense of the topographic changes
at the summit, this is what the caldera looked like
before the 2018 eruption.
This was taken in early 2018.
Here, we have the main caldera floor.
We have Halema'uma'u here,
about a kilometer or 6/10 of a mile in diameter,
and we have a lava lake a few hundred yards across.
These were recent overflows from 2015.
After the eruption, this is what the caldera looked like.
So, we have this section, this is down-dropped block,
that sank in a piston-like manner.
And we had an enlargement and deepening of Halema'uma'u.
So I'll go back and forth here
so you can get a sense of what changed.
Dramatic changes at the summit.
Now, Tricia is gonna talk
a little bit about sulfur dioxide.
Thanks.
Is my mic good?
Okay.
So Matt talked about lava
and the physical changes that we've seen.
But, especially if you live here or visit the park,
you're also concerned about what the gases
are doing at any given time.
Let's start big picture with the SO2 emissions by year.
Here's a plot since SO2 emission rates
that type of measurement started,
which was in the late '70s here.
Here's where Pu'u O'o started erupting in 1983,
and here's when that summit eruption, that lava lake began.
This really high peak over here, that's the 2018 eruption.
If we look at this Pu'u O'o era,
we had about one megatonne per year,
which is one million tonnes of sulfur dioxide per year.
That's sort of this plateau here.
There's some variations,
but it was relatively steady for a long time.
Then that lava lake opened up at the summit
and things jumped, especially early on.
It did tail off a little bit, but it was still pretty high,
at least two million tonnes a year of sulfur dioxide
that was being emitted.
Then we hit last,
or it's not last year anymore, it's 2020 now.
So 2018,
10 million tonnes or more of SO2 came out.
Remember, the eruption wasn't even that long,
it was only a few months.
That wasn't the whole year,
so if that had continued for a longer portion of the year,
we would have been looking at a much higher peak over there.
That's obviously a record breaker in terms of Kilauea,
since these kinds of measurements began in the late '70s.
And then, like I said, 2019 is over,
so now we could total those emissions up
and we have this teeny tiny little amount
that came out last year.
That's actually the lowest that we've had
since the measurements started, and 2018 was the highest.
So, we just swung from one extreme to another within a year.
And just for context,
'cause some of you may not be from around here
and didn't experience these high SO2 emission rates.
For context, the so-called dirtiest power plant
in the U.S. that emits SO2 in Ohio
is not even one million tonnes a year.
That's about this red line.
Even at these low emission rates,
we're still on par with SO2-producing power plants.
When we do have active eruptions and active lava happening,
our numbers are way more
than any individual source like that.
So now I'm gonna,
since this talk is about what's going on at the summit,
I'm gonna focus jump to 2018 and 2019, specifically.
These are emissions from during the lava lake era.
They're pretty noisy, they're scattered,
but they're in this thousands of tonnes a day range
that was coming off that lava lake of sulfur dioxide.
And then this light purple band here,
those are the events of 2018.
So you can see early on here,
when Kilauea was having those ashy explosions
early on in the 2018 eruption, up at the summit,
we did have a bit of a spike
related to those ashy explosions.
But pretty quick things died off.
And then here's our average of about 200-300 tonnes a day
from before the lava lake.
So, like I said, the lava lake was about 5,000,
plus or minus a few thousand.
Back before that lava lake existed,
it was only a couple 100 tonnes a day.
That's what that red line is.
We had that for a little while,
sort of in early fall of 2018.
But since then, all these purple dots
way down here on the bottom,
we've maxed out at about 70 tonnes a day
in these recent months.
More often than not, we're in the realm of 30 tonnes a day,
which is very, very low,
given that we've had such constant activity at Kilauea
since 1983 that brought with it more SO2 than that.
"Why is it so low now?" is people's question.
Well, we don't have any lava.
But how is that related?
When magma is deeper, that gas,
especially SO2, stays dissolved
because you have more pressure on that magma
and the gas can't escape.
It's like when you have a bottle of soda.
When that cap is on, before you've opened it,
all those bubbles are still dissolved in your liquid,
because that cap is keeping the pressure on that liquid
and keeping the gas in solution.
So that's the same thing that happens with gas in magma.
When the magma is deeper, the gas stays in it.
The difference between magma and a bottle of soda
is that your soda only has carbon dioxide in it.
Magma has a bunch of different gases,
and they all behave differently.
So, the SO2, right now, where the magma is,
the magma is deep enough to keep the SO2 dissolved.
But, carbon dioxide, that CO2, it wants to escape,
even at those greater depths.
So, we do have CO2, that carbon dioxide,
currently being emitted from the summit.
But there's a lot less of SO2,
that's what's mostly staying dissolved.
I guesss we do have a little bit,
averaging about 30 tonnes a day that is coming out.
But the thing about deeper magma
is that you just don't have a heat source
as close to the surface as you used to.
So, we've got cooler conditions,
which means water can persist.
So throw-back to high school chemistry
and I see some kids here,
you'll get this when you get to high school chemistry.
If you take sulfur dioxide and add water to it,
you're gonna get this, which is sulfuric acid,
which I'll talk a little bit about more later,
and hydrogen sulfide.
Hydrogen sulfide is a different form of sulfur gas.
That's the one that smells like rotten eggs.
If you're a local resident,
you may have noticed there's a little bit different odor
in the sulfur smells now than we used to have
with the vog from the lava lake or the Pu'u O'o era.
That's because we're getting this hydrogen sulfide.
There's still not much of it,
but you can detect hydrogen sulfide with your nose
at much lower concentrations than you can sulfur dioxide.
So even though we have a lot less
of that hydrogen sulfide now,
and a lot less of the sulfur gases in total,
you can still detect it
because it's hydrogen sulfide instead of sulfur dioxide.
It's this deeper magma
and the fact that things are cooler at the surface,
that's why our SO2 emissions are so low.
Any that we do, a lot of what we do have, then hits water
and gets converted to a different gas.
That's why the sulfur dioxide emission rates are so low.
We are still constantly measuring sulfur dioxide.
We recently actually added
these real-time plots of concentration
to our public webpage, so you can always log in and check.
There's a few different stations.
This is called Sand Hill, which is about a kilometer
downwind of the summit crater.
You'll notice these are concentrations, not emission rates.
This is just how much SO2
is in that spot at any one given time,
not tonnes per day, or anything like that.
You can see we've got a little spike here
to half a part per million,
which sure, that looks like the highest one on this plot.
But if I had a longer plot from this station,
back to the lava lake era, we'd be way up,
past the ceiling on the third floor that doesn't exist.
So, things are still very low
in terms of concentration and emission rate of SO2.
One thing that we've done recently
is actually add a different kind of gas monitoring station,
called the Multigas.
That's what this guy is over here,
and this lives on the caldera rim,
just off Crater Rim Drive.
We added that because we now have a new focus
on all the carbon dioxide that's coming out
and that hydrogen sulfide that's coming out now.
So, instead of just SO2,
this Multigas can detect those other gases.
That's still a little bit
in developmental mode at this point,
so that's why it's not quite on the website yet,
but hopefully, it'll eventually get there
after we work out some of the kinks in the station.
So I guess that's sort of the state of the gas right now.
I'm gonna turn it back over to Matt to talk a little bit
about our other new feature at the summit.
Okay, so this is a recent bird's-eye view
of what the summit caldera looks like today, more or less.
This is taken from aerial images
that we collected on December 18th.
Here, we have this down-dropped block from 2018
and this here is Halema'uma'u.
The new feature since July, is this water pond.
This is the first time that a water pond like this
has been observed at the summit in at least 200 years.
This is a virtual fly-through of the summit
giving you a sense of the topography.
Here's the scarp that formed in 2018.
This is that lower block,
other blocks that subsided during the 2018 activity.
Here's the deepest pit, this is Halema'uma'u,
and the water pond at the very deepest portion of that.
This exposure here is new,
it actually exposed an area that used to be called
the south sulfur banks.
And there we are.
There's actually a small portion
of the original Halema'uma'u crater floor
in this lowermost block here.
This morning, this is the view from the webcam,
taken from the western caldera rim.
We have Halema'uma'u, we have these fumaroles,
these have been pretty steady.
We have the down-dropped block,
the broader caldera floor, and the water pond here.
As you can see, it has this yellow,
kind of brown orange color.
You can also see this haze
and people who live on the island can appreciate that
but this is, I think, some water, some moisture,
that has gotten into the camera enclosure
because of all the heavy rain.
So, we have to, on our to-do list, is to go out there
and open up the case,
dry it out and put in some desiccant.
This water was first observed in late July.
At that time, on time of this overflight,
it was just a tiny pond, very shallow,
and it started to rise.
It has risen ever since.
This is just showing the first month of rise.
You can see it's filling
the lowermost portion of Halema'uma'u here.
At the start, it had this greenish yellow color.
Every time we go out and we measure it, we look at it,
it's a little bit higher than it was the previous time.
It's been showing a very steady rise rate,
about five inches a day.
No major changes in the rise rate.
Currently, it is about 74 feet deep.
So, pretty deep.
Going out there on our visits,
we make these measurements with the laser rangefinder,
but just with the naked eye
you can often see how much it's risen
just by comparing the water level
on rocks along the shoreline here.
This kind of steady rise, at first there was a question
of whether this was just surface runoff, rainwater,
or if this was groundwater seeping in.
The fact that, in this first month of activity
that we observed, this level just kept rising
at a relatively steady rate, regardless of rainfall amounts,
that was suggesting that this was groundwater,
the broader groundwater table, seeping in.
This is what it looked like this morning when we went out.
You can see a lot of color variation across the lake,
kind of a blue-green color here in the eastern end.
This is from the western caldera, so we're looking east.
You see these color variations.
Tricia will talk a lot more
about how the color corresponds to the chemistry.
The size, like I said, it keeps rising every day.
It keeps growing because of the flared geometry
of Halema'uma'u.
Right now it's about 190 meters, over 600 feet long,
almost 300 feet in the north-south direction.
This is east-west, north-south.
What we observed is that this color variation
is these blue-green areas in the time-lapse videos
that we take seem to be areas of influx.
Maybe fresher water, surrounding water,
that's seeping into the lake.
You can also see these distinct color bands here.
This is a time-lapse, two hours of activity,
taken from the east, so a different direction.
Obviously, there's a lot of steam,
suggesting the water surface is hot.
You can see the motion along the surface here.
What you can't really see in this video,
but you can see in others, is that these areas,
these blue or green areas,
seem to be areas where water is migrating into the pond
or flowing in.
You can see a little bit of that here.
We take thermal images of the lake
from the ground and also from the air.
They've shown that the water surface temperature
is between 70 and 80 degrees Celsius,
or about 160 to 170 degrees Fahrenheit,
relatively consistent over the past couple of months.
This is the water pond.
This is hot, obviously, heated by the magmatic system.
To give an idea of how a water pond could form
in this kind of setting, we can go through some cartoons.
It shows a schematic of cross-sections beneath the ground.
When we had the lava lake between 2008 and 2018,
we had this large lava lake, a couple hundred meters across.
We know from when it drained,
that cavity did not go down too far,
it went down a few hundred meters.
Then, it was presumably fed or supplied by a narrow conduit,
a feeder conduit, connected to the magma reservoir,
or the chamber.
This is hot, obviously, this is magma.
Presumably it would drive away any liquid water,
and you'd have what's called a steam sleeve.
We know from a well that's about a mile away
on the caldera floor that the water table here is high.
And after the 2018 eruption, when this area collapsed,
Halemaʻumaʻu collapsed and disintegrated.
Presumably, the water then had an opportunity,
once this area, these hot rocks,
this area that had been heated started to cool,
it gave an opportunity for water to start seeping back in.
Now what we have is water seeping back in,
but also trying to attain equilibrium
with the surrounding water level
of the broader groundwater table.
Presumably, in the coming months or years,
we will see this continued rise of the water level
as it seeks to attain an equilibrium
with the water level measured
kind of in the broader water table.
Again, this well is about a mile away.
How much could it arise?
We don't know with certainty,
but we know that the water level at that well,
about a mile away,
is about 50 meters higher or about 160 feet higher,
than the current water level of the pond.
If we translate that to what the level is in Halema'uma'u,
this is it, and it shows that this pond,
if it continues rising to that level,
would get obviously quite a bit larger.
Now, Trish will talk a little more about chemistry.
You haven't escaped the chemistry yet, there's more.
This top equation is the one that I showed before,
that's producing that hydrogen sulfide,
that rotten egg smell.
But the same reaction can also produce native sulfur.
If we look back at those fumaroles that Matt was showing,
there is actual yellow bright sulfur deposits
forming where some of that gas is coming out.
But what you see here is this commonality, this guy here.
That's sulfuric acid.
When you have things like that being formed at a volcano,
you can end up with an acid lake.
Kilauea isn't the only lake,
or only volcano with this weird-colored crater lake.
There's a bunch of them found around the world
in all sorts of different volcanoes, Central America;
Mexico; this is Korovin, up in Alaska; Indonesia.
There are a lot of these.
Why do they look that color?
What's going on with the chemistry?
It's not the same color,
it's not clear like your drinking water.
So, what is happening?
To get at the chemistry,
one of the first things you wanna think about is pH,
or how acidic that water could be.
Like I said, we're producing sulfuric acid
with some of these gas reactions.
So, it's likely that that acid
can end up in that lake water, but it doesn't have to.
This is a plot of pH, or acidity,
of all sorts of different volcanic lakes around the world.
This is just frequency, how many of them.
You can see there's two bumps here.
It's not uniform across the board.
We have either this acid bunch here,
this sort of cluster around the pH of one, or so neutral,
like regular drinking water, is seven,
you can have volcanic lakes that are roughly neutral.
We didn't know what we're dealing with.
We can't just walk down to that lake,
take a scoop and send it off to the lab.
This is where drones came in.
Some of you may have seen some of these videos on Facebook
or Twitter from the USGS volcanoes feed.
The lake showed up in July.
We didn't know if it was gonna stick around.
There are a lot of logistics
with using a drone in a National Park,
and we had never dealt with water sampling with one.
So, we had to figure out a lot of logistics.
This is October 26th, so the lake was three months old
when we were finally able to actually use a drone
in cooperation with the National Park,
we had to do safety permits and things
to make sure we're going about this the right way.
This is a far-out view.
This is our little hexacopter here,
and there's a string with a special water sampler,
I think it was 20 feet hanging off the bottom.
I'll jump to the next video 'cause it's got a better view.
It's a little hard to pick out,
here's the drone descending.
Here's the line, there's a sampler on the bottom.
You'll notice there's little flags
in different neon colors, there's a yellow one there,
the other ones are a little hard to see.
That was so the pilot of the drone
could use the downward looking camera
and see which flags were under the water surface,
so he knew how far down he was
and how close he was to the water surface.
There's the drone, we can still see the little yellow flag.
That one didn't get all the way in the water,
but there's pink going under.
We ended up getting a sample from about 10 to 12 feet
down below the surface of the water.
We got about 750 milliliters, not quite a liter.
It's a bottle of wine volume.
You don't wanna drink this though.
There's our water sample.
Successful, up and out from the lake,
it still had to come all the way back
to us on the crater edge, which is not trivial.
It's heavier, at that point,
so it's harder to steer the drone.
I'll jump to one more video,
which has a really cool point-of-view.
This is the camera on the drone itself.
It's looking down or hovering over the surface.
There's our neon flags on the line as it descends.
I think some of the other videos were a little sped up,
this one is slower, the suspense is building.
(audience laughing)
So like I said, this is sort of what our drone operator,
who was a pilot that we were cooperating
with from the Department of the Interior
Office of Aviation Services.
There's our splash.
And actually, when people saw this video online,
they had questions about what happened to the flags.
They thought it melted or dissolved.
It just got wet and stuck to the rope.
You can see the pink line there, it's just wet.
Once it's back up in the air,
you can see it flopping around again.
But yup, there's the water coming back out.
So like I said, we are happy with that, almost a success.
But we still have to get it back to us,
which we finally did.
We did a couple of measurements right in the field
to measure pH as soon as we got the water.
And then for more, we've never had a water lake here before,
we don't have a lab meant for doing
all the advanced chemical analysis on the water,
so we ended up sending the water away
to our colleagues in California
to do the more advanced analyses in the lab.
If we jump back to this pH or acidity plot.
Like I said, most volcanic lakes in the world
are gonna be in this neutral cluster,
or this sort of really acidic cluster.
We are not.
We're weirdly in the middle.
Which, we had seen this plot, we were expecting,
we figured it was probably acid.
We had a lot of sulfur gases,
so it's probably gonna make that sulfuric acid
and send it down this way, which it is trying to do.
But the thing is, it's a new lake.
The water is rising.
All that acid water, or what would be more acidic water,
it keeps encountering more and more new rocks to react with.
Those rocks are sort of tempering that acidic tendency
and pulling it back more toward a mild acid.
A pH of four, it is an acid,
but it's not gonna melt your hand off
or anything like that.
Different foods and juices,
and things that you consume all the time,
are in that same range.
The bottle of soda that I referenced before,
that's more acidic than the lake.
So, it's not as acidic as we might have thought it would be.
If it sticks around for a long time,
to the point where it reacts with enough of the rocks
so that it's only in contact with already reacted rocks,
then we might start seeing that acid buildup
and dragging it more toward a more common
really hyper-acidic pH.
But we don't know how long that will take.
We don't know, it may already be changing.
Other things about that chemistry.
Matt showed some pictures of those weird colors,
it's not regular water.
This is some of the basics of the chemistry,
there's our pH around four.
Other things that you notice,
that's a whole lot of that sulfate,
so that's coming from that sulfuric acid,
which is coming from that SO2 that the water is dissolving.
That high level of that sulfate is showing
that we have that dissolving of SO2 into the water,
which is a process called scrubbing.
And then they were able to determine that this mineral,
called gypsum or anhydrite,
is actually saturated in the water,
so we have little solid bits of that mineral
sort of suspended in the water
or raining out of the water as a solid.
The little bits of this solid gypsum
or anhydrite in the water.
If that wasn't happening,
this calcium number and the sulfate number
would be even higher.
We're actually losing some of that sulfur
to that solid phase.
The other thing you notice
is we have this really high number for magnesium.
That's because Kilauea's rocks are really high in magnesium,
so that reaction of the acid with the rocks
is basically dissolving those rocks to some extent,
and all that magnesium is ending up in the water as well.
And then we have these weird colors.
This is a picture of a filter
that the gross weird yellow water was filtered through,
and the filter ended up
with this mustardy-orange crust on it.
In some cases, you can actually do analysis
on that solid material
and figure out exactly what those minerals are.
Unfortunately, that didn't quite work out.
We have some guesses as to what that might be
based on the chemistry of the water,
the chemistry of the rocks, and the colors,
so it could be some minerals
that are rich in that same sulfate,
'cause we got a lot of that, and iron.
Minerals like jarosite or schwertmannite,
which I had never heard of until we had this lake.
Matt alluded to this, that color is not static.
Any volcanic lake can change color.
These are some examples from Indonesia, Kelud volcano.
This is the only volcanic lake
that I could find a picture of online
that has a similar orangey-rusty color
as our lake currently does.
But, as you can see, at different times
that same lake at that volcano
could be sort of greenish-yellow, or this orangey-brown.
Now they think...
Someone's hypothesis was that the orangey-brown
was related to it being a dry season.
Which it's currently not dry here,
but our lake is still orange.
So, something's different about our lake.
And then this is really cool.
This is another volcano
that has three different crater lakes,
all in close proximity.
It's crazy, you can see at any given time
all three lakes are different colors.
Then they change to different colors,
and they're different from each other still.
Unfortunately, I couldn't find any literature
about the actual chemistry of these lakes.
But I did find an example of a volcanic lake in Japan.
Their color change is more subtle,
but it is sort of in that yellowy-greeny range
that our lake was originally.
What they did is use a device called a colorimeter,
which can actually look at the surface of the lake,
or anything,
and actually quantify the color and the contributions of red
versus the green versus the blue
into that ultimate single color.
They were able to get samples of their lake,
measure the chemistry,
and then compare it to that quantified color
at any given time.
They were able to say, the blue stuff, that's sulfur.
Native sulfur, like I showed you in one of those equations,
is depositing and the interaction of the light
with that sulfur can make the water look bluer.
But once you start getting different forms of iron
interacting with the light in the lake water,
you can head in a green direction
or a yellowy-orange direction.
They stuck mostly in this green to blue area.
We are definitely in the yellow-orangey range.
Matt actually is currently, we didn't buy one yet,
but he's renting a colorimeter
and he just got to try it for the first time today
because the clouds finally parted.
That is a tool that we're thinking
about using in the future to try
and quantify these color changes that we're seeing,
because we have had color changes.
This is about a week or so
after the water was first noticed.
It's sort of greenish, maybe a little blue tinge in there.
Then as time went on, we started getting yellow,
especially in the middle.
Then it was sort of a more uniform greeny-yellow.
This was just a couple of days
after we got the water sample via the drone.
You can start to see a more orangey patch forming over here.
Then it's gotten progressively more orange, rusty color.
But, like Matt said,
you can still see these more greener tinges
at the edge where we have
what's probably that influx of groundwater
that hasn't yet reacted with as much volcanic gas.
So, like I said, we got a water sample here
just a couple days before this.
It was somewhere in the middle,
so somewhere yellow-colored sample.
We're actually hoping in the next week or two.
We've been working with the Department of the Interior
to get permission from them to do a sampling mission again.
Now we're in the phase where we're working
with the National Park to secure permission from them.
Hopefully within the next week or two,
we'll be able to get another water sampling mission done.
This time, because we know we have these different colors,
we're gonna try and get more than one sample.
Try and maybe get one right at the edge
of that greener color.
And then something in the yellow range,
and then from the darkest rusty-brown
just to see how that those different colors
vary with the different chemistries,
or if there's different chemistries.
Maybe everything's playing a trick on us
and there's really not that much of a chemical difference
between the colors,
but we're hoping that, like I said, in the next few weeks,
we hope to have some more news
on whether the chemistry has changed much,
whether the pH has changed much.
Because at other volcanoes around the world,
some of those chemical changes can give indications
about how much sulfur is coming out.
'Cause like I said,
we're measuring low sulfur emissions right now,
but that's 'cause a lot of it is ending up in the water.
So, we're trying to better quantify
how much we're actually losing to the water
by getting another water sample
and looking at the chemistry of that.
Now, Matt is gonna talk about some other aspects,
or implications, of what this water lake may mean.
Okay, so the water pond is interesting,
but it's also a potential concern
because when magma interacts with water,
it can trigger explosive activity.
That's obviously would be a hazard at the summit,
or a potential hazard at the summit.
This happens at many volcanoes worldwide.
These are two crater lakes
that have had frequent explosive activity,
Poas in Costa Rica, and Ruapehu in New Zealand.
This is obviously on our minds,
the potential for explosive activity, in particular,
because there is precedent at Kilauea in the geologic record
and there is a long history of explosions at the summit
that have affected the entire summit region.
This is the Keanakako'i explosive sequence
that occurred in the 1500s, 1600s, and 1700s.
Some of these explosions are thought to have occurred
or have been triggered by magma rising up
and interacting with water, groundwater or surface water.
This is one of those units, so this gives you an idea
that the deposits in the summit area
are up to 11 meters thick.
That's the kind of cumulative deposits
from 300 years of activity.
But this is just one unit, unit D,
and you can see 10 centimeters of ash deposited.
This is the Golf Course subdivision.
These larger scale explosions
that have happened in the past at Kilauea
have the potential to affect areas outside of the caldera.
So, this is obviously on our minds,
and one of the concerns related
to the presence of water at the summit.
The difficult thing is that the exact processes
that triggered this explosive activity
because this is long ago,
there wasn't modern instrumentation to track this,
the exact conditions that trigger the explosive activity
are still not completely understood.
Most likely, explosive activity in the future
would be preceded by detectable precursors,
such as rapid inflation or increased seismicity,
that indicates magma is rising.
However, at crater lakes there's always a small chance
that small steam blasts, or phreatic explosions,
can occur with little or no warning.
Just the presence of water alone
doesn't guarantee explosive activity.
We know that there's an extensive water table at the summit.
We've had many previous eruptions, fissure eruptions,
that presumably traveled through that water table.
Fissure eruptions in the '70s and '80s,
for instance, that did not trigger explosive activity.
So, there must be other factors, in addition to water,
that controls whether an eruption
is explosive or non-explosive.
For instance, perhaps it relates also to the rate
at which magma rises.
Faster-rising magma might leave less time
to drive or boil off the surrounding water
and lead to explosive activity,
whereas slower-rising magma might allow time
to boil off and have a non-explosive eruption.
It's still not completely understood.
Because of this concern
for the potential of explosive hazard at the summit,
we're continuing to keep a close eye on the summit.
We have webcams.
We are making routine measurements of the water level,
because water level alone at other crater lakes
has been a potential precursor to explosive activity.
I'm sorry, abrupt changes in the water level.
Thermal measurements again,
tracking the temperature of the water pond at other places
has been a sign of changes and hazard.
Of course, we're going out
looking and just making routine visual observations.
Changes in the color, like Tricia talked about,
at other volcanoes and other crater lakes
have also been potential precursors to changes in activity.
Routine overflights.
And Kilauea has one of the densest
geophysical monitoring networks of any volcano on Earth.
So, we have this existing network
that we're of course always keeping an eye on.
What's happening beneath the surface?
Over the last year, we have inflation
that began earlier in 2019.
This inflation rate is actually higher
than what was happening in the years before 2018.
And this basically makes sense,
we had a large draining event of the summit magma chamber
and now magma is recharging that chamber.
We also have elevated seismic activity at the summit
when you compare it to the years prior to 2018.
Over the last six months or so,
we've kind of had this occasional small swarms
of tiny earthquakes.
Overall, there's no detectable signs
or obvious signs of imminent unrest or precursory activity
that would lead to explosive activity in the near future.
No signs of imminent unrest at the summit.
We have this water pond, it's relatively stable,
we have a slow and consistent rise in the water level.
We have these minor moderate changes in color.
We have this inflation,
this is indicating that the magma chamber is recharging,
as we would expect.
We know the magma is still relatively deep in the system.
Tricia talked about the SO2 emissions
and how some of that's complicated
by the presence of the pond
potentially absorbing some of that SO2.
We have seismicity that's elevated
compared to pre-2018 levels,
but it's not at an alarming level.
Don Swanson, who's worked at the summit for many years
has said something along the lines
that this is the most exciting period of activity at Kilauea
that he's seen in his career
because we're obviously in a new era
that we haven't seen in many years.
I think we're all interested to see what's next.
I have to show and share
all of the future talks and activities
that are going on with Volcano Awareness Month.
And I'll just leave this here.
And I think Janet is here
and she can provide more details on these events.
There's more information on our website.
And actually what I didn't mention
is that obviously this is an exciting time on Kilauea.
Because things will eventually change,
I encourage everyone to keep an eye on our website
and keep an eye on our updates.
We have monthly updates about activity,
regular updates that can be found here.
On behalf of Tricia and myself, we wanna thank you.
(audience applauding)
