Steamboat Geyser erupts again! Strange things about it...

In this post I am going to quickly talk about the most recent eruption from the time I am writing this. The most recent eruption was the 9th one of 2019 (also the 41st eruption since it reactivated in early-2018). This recent eruption carried the smallest amplitude ever recorded on seismic station YNM, the closest station to Steamboat Geyser. Although the amplitudes were much smaller, it is surprising to note that this eruption put out more water than the previous eruption. As usual, please click the title of this post or "read more" to continue...

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Steamboat geyser in the steam phase of eruption on March 16, 2018, just a day after the first water (hydrothermal) eruption of 2018. Photo taken by Behnaz Hosseini.

First off, if you wish to see my Steamboat Geyser 2019 page, which includes the most recent eruptions, then please go up to the seismic events dropdown menu and click "Steamboat Geyser (2019)". Also, don't forget to check out the 2018 page too!

So Steamboat Geyser erupted again last night. Here are the seismogram, spectrogram, and spectra plots of this eruption:

Note that this eruption carried the smallest amplitudes ever recorded by seismic station YNM for the Steamboat eruptions. Below is the 3-plot image I generated for the 8th eruption of 2019, the eruption right before last night's:

Notice the 8th eruption of 2019, shown directly above, was stronger than the 9th eruption of 2019, shown right before. So obviously it was a smaller eruption, right? Well hold on a second. Take a look at the following image. It is of the Tantalus creek stream gauge which can detect the amount of water ejected from the Steamboat eruptions:

So although the most recent eruption was much smaller in amplitude than the eruption just prior, the stream gauge data from Tantalus creek proves it was not smaller! The 9th eruption put out much more water than the 8th eruption, even though the 9th eruption was smaller. Isn't that strange? Also, as you will see in the slideshow directly below, this 9th eruption was also detected on seismic station YNR which resides to the SE of YNM and Steamboat Geyser. How is that possible if the weaker eruptions never used to show on YNR? What changed? Here, check it out:

So notice how on YNM there was a small burst in the eruption about 12 minutes or so prior to the main eruption burst? Well look at YNR! You can see the same increases in energy at the same exact times on both stations. So YNR definitely did detect this eruption. So how is this possible now when it wasn't before, in regards to eruptions weaker than 15,000 amplitude count? The only difference is that YNM is detecting much lower frequencies than YNR is. This can be seen especially on the spectra and spectrogram plots.

Since these eruptions still carried very low amplitudes, some of the background noise was getting in the way. So, in order to draw out these eruptions only, I decided to add an intricate filter to both plots. As you will see below, I did a pretty good job at drawing out the Steamboat eruption only! Note that YNM has a strong band pass filter of 11Hz to 25Hz. Also, YNR has a high pass filter of 18Hz. Both these settings on both of these 3-plot images will eliminate almost all background noise and will show only the eruptions. As you can see, it was detected on station YNR. But why? Something must have changed.

The U of U webicorders of YNM and YNR. The Steamboat eruption is close to the middle of the chart and is so small it is hard to see. Again, if this eruption was the smallest ever recorded then why did it put out much more water than the last eruption that was stronger? Very odd. Let me know what you think!