Watching Rainier


After the magnitude  6.4 quake that struck just off Vancouver Island Sept. 9th, I was asked what volcanoes I would be watching because of that. I had just posted an article here on the Earthquake-Volcano Connection in which I outlined the long-term effects of earthquakes on the magmatic systems of volcanoes.

I was asked if I would be watching Mt. St. Helens after that quake, and said yes, and that I would also be watching Mt. Rainier, and so I have. This morning a second quake (4.1) occurred very near where that 6.4 hit on the 9th, and so I’m watching Rainier and St. Helens all the more intently.

Rainier, as long as I’ve been watching it, has been a relatively quiet volcano, with background seismicity including many small type A events and glacial activity showing up for the most part, however since the Vancouver quake on the 9th there have been a few larger than normal seismic events there that might be worth mentioning.

Ranier 09-15 STAR SHZ UH

A magnitude 2.4 quake was recorded on the 13th under Rainier, and a 1.5 on the 14th. This morning  we see this event on the right.

In general and overall Rainier has been a bit more internally noisy of late, so it’s magmatic systems definitely did ‘feel’ that quake on the 9th, and the energy transmitted by that quake may be having some effects at Rainier. Not to say that anything bad is about to happen there, but the increased seismicity there since the 9th seems to show that earthquakes do influence the magma chambers and magmatic systems of volcanoes at a distance.

STAR SHZ UH Sept 9 Vancouver quake

The Sept. 9th quake registered strongly on the STAR seismograph high on the west flank of Rainier as shown here. Since then things seem to have picked up there somewhat. On Sept. 12th the RCM station at Rainier registered some increasing seismic noise there which I found noteworthy.

Rainier RCM 09-12 increasing activity

This record from Sept. 12th  starts out with what for Rainier is quite normal background seismicity, and then gets noisy for quite a while. This noise continued for the next six hours and is something I’ve never seen there as long as I’ve been monitoring Rainier, which has been quite a long time. It quieted down the following day, but has started up again this morning. I had thought to check and see if it might be glacier movement, but can find no news items about glacial activity at Rainier, nor anyone I could write to and find out from. I think that had a glacier been moving down the flanks of Rainier for six straight hours on the 12th it would have been noted and something said somewhere online, but I see nothing about it, and the seismic activity for the 12th is far in excess of any glacial activity I’ve seen show up there.

So at least on the Seismographs there Rainier is more noisy these last few days, and has gotten my attention. After the second quake at Vancouver Rainier will be all the more interesting for me.

Later that same day…

After this morning’s seismic noise at the RCM station at Rainier we see the following:

Rainier RCM 09-15 tremor

I’m thinking this is probably not wind. At the STAR station on the other side of the volcano we see:

Ranier 09-15 STAR SHZ UH (2)

Well… that’s probably not wind either.

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About Martina Vaslovik

Volcano nerd and seismogeek
This entry was posted in earthquake, Mt. Rainier, Uncategorized, Volcanology. Bookmark the permalink.

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