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Hi, everybody.
I'm Mike Poland, the Scientist-in-Charge
at the Yellowstone Volcano Observatory.
And I'm here with the update for November 1st of 2019.
I thought before we dove into the discussion
about the earthquakes and the ground deformation,
we could talk a bit about Steamboat
since of course the eruptions there are continuing.
And I wanted to show you the temperature record
in the Steamboat outflow channel.
This is a thermometer basically that's stuck in the channel
that's draining Steamboats.
So whenever there are eruptions,
the water will pass over this thermometer,
and then the day that we get radioed in
and we can record it and actually show it in real time
on the YVO website, if you go to the monitoring page.
So there were five water eruptions of Steamboat Geyser
during the month of October.
And you can see them all right here in this plot.
This is showing the temperature over the entire month.
So here's an eruption on October 1st,
and then you can see right after that eruption
the temperature went down.
And then we were seeing kind of
the daily temperature variations of just air temperature.
And then all of this sort of wiggling up and down
are minor eruptions, so basically the geyser starting
to heat up, smaller eruptions are occurring.
And then we get another eruption there on October 7th.
It immediately goes right back down to just air temperature.
Then it starts up again.
Minor eruptions until another one on October 16th.
Again on October 22nd, and then on October 30th.
So we have these five water eruptions,
but each one was preceded by up to a couple of days
of this minor eruptive activity.
And that's something that's
pretty characteristic of Steamboat.
And it's kind of neat as well to see that sometimes
the minors only last for a couple days,
sometimes they last for many days.
And there isn't a real pattern in just how long
that minor activity occurs
before the big major eruption happens.
So you can go online and you can see this
on our website anytime.
It's updated daily, so you can keep track
of Steamboat eruptions even when there's no one there.
And unfortunately that's gonna happen
because winter conditions are coming to Yellowstone,
and park roads are gonna close on November 4th.
But we'll still keep this updated.
All right, well let's dive in and have a look at the data
for the month of October.
During the month of October, the University of Utah
seismograph stations, which is responsible for the operation
and analysis of the Yellowstone Seismic Network,
located 193 earthquakes
in the Yellowstone National Park region.
The largest event was a magnitude 2.9,
located right here on October 16th
at about 11:00 a.m. Mountain Time,
sort of between Mammoth Hot Springs
and the Mount Washburn area.
In addition to all the normal seismisty
that was scattered throughout the region,
there were two seismic swarms during the month.
The first occurred right here.
It was just on the western boundary of the park.
It included 39 earthquakes,
the largest of which was just a magnitude 2.1,
and it occurred in October 4th lasting through October 12th.
A largest form was south of the Mammoth Hot Springs area
and included 87 earthquakes
between October 26th and October 31st.
The largest magnitude earthquake in this form
was a magnitude 2.6.
These sorts of swarms are pretty common
in the Yellowstone region throughout the year,
and they account for roughly 50%
of all the seismisty in the region,
rather like this month, where they account
for about half of all earthquakes
that were located during October.
In terms of deformation, we didn't see a whole lot
of big changes at Yellowstone over the last month or so.
This is vertical deformation at the White Lake GPS Station.
Downward trends means subsidence,
and upward trends mean uplift.
So over the last two years,
you can see this trend of subsidence dominates.
Over the last two months,
the deformation's been somewhat variable,
with subsidence and then possibly a slight bit of uplift.
But the net deformation has basically been zero
over the last couple of months.
Looking at the Mallard Lake resurgent dome,
this is represented by a GPS station
that's located at Old Faithful,
you see the same general trend of subsidence
over the last two years.
Over the last two months, there was a bit of subsidence,
and then that sort of bottomed out in October.
So there hasn't been much net deformation recently.
Perhaps more interestingly is at Norris.
Norris had been uplifting since 2015,
and in October or so of 2018, that stopped.
And you can see how basically there wasn't much deformation
at Norris up until about September, October
of this year when Norris started to subside.
So we're starting to see it looks like the onset
of subsidence in the Norris region.
We'll have to keep an eye and see how that progresses
over the coming winter.
Finally, if you'd like more information, you can always go
to the Yellowstone Volcano Observatory website.
You can find our monthly dates there.
You can also go and look
at Yellowstone-specific information,
the current alerts, background information on geology,
history, hazards, all of our monitoring data
are accessible via the monitoring tab.
And our weekly "Caldera Chronicles" article
you can always access right here.
And remember, if you have any questions,
you can always reach out to us via email
at yvowebteam all one word @usgs.gov
We're always happy to answer
whatever questions you may have.
Well, that does it for the November update.
Hope you have a great month,
and we will see you again in December.
Take care.
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