Wednesday Whatzits: Redoubt returns to normal and swarms at Long Valley

The big geology news right now is the M8 earthquake in American Samoa that generated a killer tsunami (which made it all the way to the Bay Area in California).


Mammoth Mountain in California's Long Valley region.

In more benign, volcano-related news:

  • The aviation alert level at Redoubt in the Alaska has been returned to Green/Normal, which means that for all intents-and-purposes, the eruption that started earlier this year is over. The new dome totals ~91 million cubic yards of lava, slowly adding back to the north side of the volcano.
  • Eruptions reader Doug C. pointed out to me that there was a couple small earthquake swarm (see the update for 9/28/2009 and 9/29/2009) this week at Long Valley/Mammoth Mountain in California. The earthquakes were all fairly small, in the M1 range - and deep, at ~20 km / 12 miles depth. Just shows that there might be magma burbling around down there somewhere, but this doesn't seem like much beyond some transient noise (and the alert level stays at Green/Normal).

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Karl

It appears that was an earthquake but not on Redoubt itself.

By theroachman (not verified) on 30 Sep 2009 #permalink

The tsunami wave photo. You will need to hit the 'prev' button on the screen about 13 times to get to the wave photo. Sorry that is the way the link works

http://www.nzherald.co.nz/nz/news/image.cfm?c_id=1&gal_objectid=1060056…

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Callan

Great write up on your visit to Long Valley. Did you get a chance to make it over to Devil's Post Pile or is that area still closed?

By theroachman (not verified) on 30 Sep 2009 #permalink

I wonder why there was no comment on the massive quakes that triggered Tsunami Warnings and killed scores of people within 24 hours.

The Quake that hit Indonesia happened in a region that includes the the most explosive volcano's which includes the region of lake Toba, the remnant of a eruption that almost caused human kind to go extinct.

There is a suspect connection between powerful quakes and volcanic eruptions.

The Pinatubo eruption happened within a year after the region was hit by a big quake.

There is also a most fascinating link between solar minimum (low solar pressure) and seismic and volcanic activity.

All these theories can now be tested as we find ourselves in a front seat row as nature is conduction a gigantic experiment.

Due to the current solar minimum, cosmic ray levels are up 19% compared to the last maximum values which allows us to test the Svensmark theory stating that the stars in our universe dictate cloud cover on earth which is responsible for warming and cooling cycles in our climate, instead of man.
It would be a discovery if we would find a confirmation of a link between our sun with volcanic eruptions.

There are reasons to assume this link is real.

During the Medieval Warmth period there were ample volcanic eruptions. The same goes for the past century which showed an active sun.

But during the Little Ice Age, the Maunder- and Dalton Minimum earth experienced about five VEI 7 eruptions per century.

These truly are interesting times.

http://wattsupwiththat.com/2009/09/29/nasa-cosmic-rays-up-19-since-last…

By Ron de Haan (not verified) on 30 Sep 2009 #permalink

Just don't camp on naturally occurring CO2 vents if you're on Mammoth Mountain.

@Origuy: Look at footage of a real tsunami (there's an awful lot thanks to cameras being common and the tragedy in the Indian Ocean); you don't get "bigger waves". You have normal waves and in many cases the water level is observed to receed (if the tide is low during high tide, run away). Then the whole ocean seems to swell and wash over; that is a big wave, but it's so big you probably don't see it coming, you just see the water rising quickly. You will see your usual wind-driven waves on top of the big 'un.

Short story: You get 1 *huge* wave, not an increase in the size of the usual waves you see.

By MadScientist (not verified) on 30 Sep 2009 #permalink

Ron: five VEI 7 eruptions per century during the Little Ice Age??? Could you give details please, because apart from Tambora 1815 I'm not aware of any in the last 1000 years.

Tsunamis are poorly understood by the average person. Even after all the Indonesia footage folks expect to see an enormous breaker, the kind surfers drool for.
They're more like a really quick extremely high tide. Normal waves are tall and wide but short from front to back. Tsunamis can be miles from front to back, so the wave just keeps piling up onto a shore.
Every documantary I've seen goes ahead and shows huge foamy breakers from the North Shore. Great for catching a curl, but not accurately informative with respect to tsunamis.

According to the news there were 4 tsunamis; I won't have time to look up any seismic records though - I'd expect 4 large shocks if there were 4 waves but my local newspaper doesn't mention multiple shocks. I wonder if there was anyone out on a ship in the region who can tell us about the "maremoto".

By MadScientist (not verified) on 01 Oct 2009 #permalink

You dont need 4 shocks to get 4 waves.
Most tsunamis are caused by a vertical displacement of the ocean floor, either up or down on one side of a fault. That sets a large mass of water basically pouring towards whichever is the new low area. Thats your first wave.
Subsequent waves are just the sloshing effect, just like ripples in a pond when you drop in a rock.
Worst part is the water level going down just before a wave hits. It draws the curious closer to the beach.

I flew over Redoubt twice on a commercial flight in July. Some aviation warning! The view of the degassing lava dome was great though, so I'm not complaining.

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