Bear in mind when, I say seismic data, I'm not talking about the number of earthquakes or tremors that occur or their severity, but rather seismic activity--some natural, some artificial--used to map out the two remaining magma chambers beneath the Yellowstone caldera. And considering that catastrophic supereruptions have occurred in the Yellowstone caldera on average every 730,000 years, you can't say that Yellowstone is overdue for a supereruption.
Don't forget too, a lot of that heat from the mantle plume is dissipated in non-explosive eruptions of the low viscosity mafic magma extruded as basaltic lava surrounding the rhyolitic area that makes up the Yellowstone caldera. Could another supereruption occur. Sure! It's possible. Is it likely. No. It's very unlikely. We will see eruptions from the Yellowstone caldera, but at most, they will be comparable to the typical eruption of a composite or stratovolcano like Mt. Redoubt this last year....certainly nothing nationally, much less globally catastrophic.
Consider a larger plume than is found at Toba or most any other site.
The enormous size of Yellowstone caldera suggests that it could have an extraordinary charging system, unlike the slow and steady systems seen elsewhere.
We really have nothing to base our best estimates on how quickly it can become truly active to the point of bursting the plug and having a massive eruption . I am not wishing for this event. We study it closely so as to grasp as much information as we can. No one can determine how much notice we shall have . It remains a natural wonder.
There is no way to be certain about the timing of events, hence the extremely large error bars associated with the estimates of recurrence times. However, even with those error bars, there are long intervals between eruptions at Yellowstone. The chances of a major eruption event at Yellowstone in the next 1000 years is essentially 0.0. Beyond that point the probabilities begin to grow very slowly.
If hot spots are not stationary, it is interesting that they always seem to move opposite the drifting plate.
Unless someone has an example of a hot spot that moves in the same direction or at right angles to a plate?
And you have to remember too that when they're talking about whether or not plumes are stationary, they're talking over long periods of time.
Lava Creek Tuffs. So we are actually in the historic time frame for another major eruption though it could still be a couple hundred thousand years off.
I want to thank you guys for the interesting opinions and the links.
The concept of the plumes moving, even that one, much like Hawaii's is
most interesting .
On the question of activity, is it 600,000 or 730,000 years, or is the range of opportunity nearly open ended or just wide spread?
The YNLV Hotspot (Yellowstone-Newberry-Long Valley) is an intresting study, as it apprears there might be part of the same system.
On your question on timing, Dan, most volanoes tend to exhibit cyclic behavior. They erupt, then go quiet while thier magma chamber refills, then they erupt again.
Mt. Redoubt erupts about once every 20 years.
St. Helens erupts about once every 150 years.
Neberry Caldera erupts about once every 2500 years.
Yellostone area has an minor eruption about once every 70000 years, and a supereruption about once every 700,000.
These are basically averages over the life span of the volcano.
It's driven by quite a few variables, such as:
How fast the magma chamber refills, which can change over time. (Yellowstone appears to be slowing down it's fill rate)
What kind of magma the chamber is fillign with. Fluid bassalts can fill a chamber faster then less fluid ryolites or ascendites.
The condition of the volcanic chimney left from the last eruption.
there are quite a few other variables as well. So the cyclic behavior is just really an average, as volcanos age, thier behaviors change over time.
Very well stated, dgavin and quite accurate!
Hi, As yet, have we any way of sounding the dimensions of the magmatic chamber at a depth of 25 kilometers? I think that mystery may remain unsolved for quite some time.
Far as I know Yellowstone cladera is a single chamber volcanic system.
The main Magma chamber is sort of U shaped the upper forks of the U as close as 8km to the surface, and the base of the U as deep as 20km. The bulk of the Magma lies at about 12 km average debth.
There may be a very deep lower magma chamber, but I have not heard of any such chamber being seismicly detected as of yet.
Hi, Interesting links and lucid practical information. Thank you.
Thanks for the links dgavin. Interesting.
Yellowstone hit by swarm of earthquakesMost are less than magnitude 1; too small to show at USGS map.Yellowstone National Park has been rattled by more than 250 earthquakes in the past two days following a period of 11 months of quiet seismic activity in the park.
The quakes have been gaining strength, with a 3.1 tremor recorded at 11:03 a.m. today. A 2.9 quake was recorded at 12:38 p.m.
Prof. Robert B. Smith, a geophysicist at the University of Utah and one of the leading experts on earthquake and volcanic activity at Yellowstone, said that the activity is a "notable swarm."
"The swarm is located about 10 miles northwest of Old Faithful, Wyo., and nine miles southeast of West Yellowstone, Montana," said Smith.
It's looking lively. The strongest events so far (in order) were 3.1, 2.9, 3.4, 3.0 and 3.3 magnitude. While most of the quakes were at a debth of 8-10km, there have been two of the more recent ones (in the 2's magnitude) a debths of less then one km.
There has also been two minor (very minor) sort duration harmonic tremors following some of the quakes. This swarm event was also preceeded by a longer duratation harmonic tremor on the 15th, however it was also a minor tremor.
The rapid decrese in debth towards surface events, is telling me that this is likely a hydrothermal event, and not magma. At this point i'd guess that these events will trail off in about a weeks time. I also don't think there will be any magma eruptions, or hint of magma activity. There might be a slim channe of a new gyser forming, or of some alteration to existing gysers. However take this with a grain of salt, a few days of seismograph readings are really no basis for anything but a guess, at best.
You know I was wondering, could the earthquake in Haiti have anything to do with the swarm now hitting Yellowstone? A resonance of a sort?
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According to USGS 490+ events and still going. They have released an info statement indicating it's Tectonic (Fault related) activity, and not volcanic or hydrothermal.
I'm seeing atleast 4 2 minute duration harmonic tramors on todays seismograph alone, one of them obviously so. So i'm going to stand by my hydrothermal assement for a while longer.
I'll work on some charts (time/debth) (Time/Position) tonight of the events to date.
I have the charts done, and will export them to graphics for posting here tonight sometime.
People can wind down thier doomsday clocks!
Look like this swarm of earthquakes might be approaching it's end.
Only 4 events logged today compared to 32 yesterday (for the same time frame).
Also the Haiti quake was not unusual as far as annual quakes around the world go. There are and have been quakes of that magnitude every year somewhere in the world. If they were going to shake anything loose, it would have happened long ago.
Just a comment on the hydrothermic event potential: I was just in Yellowstone last Fall and saw a number of craters from extremely large hydrothermal explosions. While they may not be as exciting as the magma dome rising, they can still be relatively large events.