(upbeat music)
- Hi everybody.
I'm Mike Poland, the scientist
in charge of the Yellowstone Volcano Observatory,
and this is the monthly update for April 1st, 2023.
April 1st, April Fool's Day.
It's a time when some humans
might like to prank one another.
We thought it might be a good occasion to talk
about when animals prank humans.
This is actually something we see
in the volcano world pretty often.
For example, there might be herds
of elk or bison that pass by a seismometer.
They make a lot of noise.
These are large animals.
Now that's noise that we can filter out.
We can still see small earthquakes
when these herds are walking by.
But it's sort of a funny thought to think
that maybe these animals are kind of pranking us
as they're making a lot
of noise cruising by these seismometers.
Some of the seismometers that are out
for research deployments have been kicked by animals,
and it's kind of a funny thought to think maybe the bison
saw this and decided they were gonna play soccer with it.
We also see animals interacting
with some of our permanent stations.
Now, generally, we try to keep these stations
out of the way.
Of course, we want to coexist with the environment
so when we install a seismic station or a GPS station
we put it in a place that won't impact plant
and animal life to the extent that we can.
But just like humans,
animals are curious and when they see these things
they might go up to investigate.
We've seen plenty of evidence
of bison nose prints on solar panels
or bear paw prints on solar panels, and occasionally some
of the smaller critters might find some
of the wiring interesting, and they'll yank the wires
right out of the instrument boxes, birds and marmots
and things like that.
That causes the instrument go down.
So we have to go back and maybe do some repair work.
A lot of curiosity there just like humans.
A lot of pranks on those animals
just like humans might do to each other.
All right, now let's talk about what happened
during the month of March in Yellowstone,
including a little bit
about a small seismic swarm that occurred
in the north part of Yellowstone Lake on March 29th.
Seismicity in the Yellowstone region
in March was slightly above average, and this was mostly due
to the occurrence of two swarms in the park.
The University of Utah Seismograph Stations,
which operates the Yellowstone Seismic Network,
located 354 earthquakes during the month.
The largest was a magnitude 3.7, and it was part
of a swarm of about 106 earthquakes that occurred
beneath the north part of Yellowstone Lake.
This got a fair bit of attention
because it had these two magnitude three events,
a 3.7 and a 3.1, and occurred mostly on March 29th.
But that wasn't actually even the largest swarm
of the month in terms of numbers of earthquakes.
That belongs to this swarm over here that occurred
near West Yellowstone
between March 13th and March 18th.
There were 147 events that were part of this swarm,
the largest being a magnitude 2.7.
Aside from these two swarms, seismicity was scattered
throughout the region, and as usual,
most of it occurred in this area between Hebgen Lake
and the north central part of Yellowstone National Park.
This is the most seismically active part of the park.
And just to give you a little flavor
of what these seismic swarms look like
on our seismic records, this is the record
from Pelican Cone, a seismometer located in that area.
You can see it was quiet
through the 28th into the morning of the 29th,
and then the earthquakes just started to bang away.
And this is what a swarm looks like,
a number of discrete events.
Sometimes they happen so close together
that they're hard to tell apart from one another.
And there is the magnitude 3.7 right here
that occurred at about 8:24 in the morning, Mountain Time.
And after these events
it sort of petered back out,
just a couple of scattered ones.
This is a pretty typical swarm for the Yellowstone region.
Nothing really special about it.
About 100 events with magnitude threes is not unusual
in the Yellowstone area.
Now looking at deformation in the Yellowstone region,
we've seen continued trends
of what's been going on actually for many, many years.
Since 2015, Yellowstone caldera has been subsiding by a rate
of two to three centimeters, about an inch or two per year.
This is the last two years
of vertical deformation at the White Lake GPS station
on the east side of the caldera,
and each one of these blue dots represents a day of data.
And over the course of this two years
there's overall subsidence,
and you can see during the summer months
there's a little bit
of uplift or a pause in that subsidence.
That occurs as groundwater was recharged by melting snow.
That snow melt sort of puffs up the ground like a sponge.
And it lasts through the summer
and then you can see right here
in October we switched back to subsidence
that's been ongoing since the end of last summer.
If we go to the west side of the caldera
near Old Faithful on the Mallard Lake resurgence,
the story is much the same.
We had these summertime pauses in subsidence
or little bits of uplift, and then once the summer ends
here in October we go back to that subsidence
of a few centimeters, an inch or two per year.
Also see the same thing in the Norris area.
Norris doesn't have quite as much deformation
over the last few years as we've seen in the caldera,
but there's that summertime uplift
that occurred summer of 2022, again into October,
and then back to a slight amount of subsidence,
a couple of centimeters at this point,
just about an inch since the end of last summer.
And finally looking at the largest geyser
in the world in terms of eruption, Steamboat Geyser.
Unfortunately our temperature monitoring stations
continue to be down,
but there is the stream gage on Tantalus Creek
and that is where all of the water that comes
out of Steamboat Geyser eventually flows.
So we can use the stream gage to detect any eruptions
of Steamboat Geyser.
Now, these spikes that you're seeing here and there
throughout the month of March,
these are all related to storms, precipitation.
We don't see any spikes that are related obviously
to geyser eruptions.
It's possible there may be something hiding in there
but it doesn't look likely.
If you look at January when you had eruptions right here,
January 5th, and another one on January 28th,
those spikes are very, very apparent.
We don't see those at all in March, so it appears
that Steamboat has stayed quiet since the month of January.
Well, that does it
for the monthly update for April 1st, 2023.
Now remember, if you have any questions at all
or would like more information,
feel free to email us anytime.
Our address is yvowebteam, all one word, at usgs.gov.
We'll be back next month with the May 1st update.
Until then, please stay safe, stay healthy
and we'll see you next time.
Bye-bye.
(upbeat music)