Is The Yellowstone Caldera Calling? (external - login to view)
- SCIENCE/HEALTH/CLIMATE/NATURE (external - login to view)
Over the last few months things have been heating up in our famous National Park and none of it is good.
Over eight days, more than 1,270 mostly tiny earthquakes have struck between Old Faithful and West Yellowstone. The strongest dozen or so have ranged between magnitudes 3.0 and 3.8. These are beginning to become serious in size, as a growing swarm of course, but the vast majority have been too weak to be felt even nearby.
Here is why I am not dismissing this latest quake swarm out of hand as another in a long series of false-alarms.
Ever since the Boxing Day Quake in 2004, the entire Pacific Ocean tectonic Plate has been re-adjusting. As a result, we started seeing increases in seismic events traveling north along the Japan Islands and South along Malaysia into New Guinea/Fiji/New Zealand. There followed more quakes traveling east alone the north and south edges of the plate, which being lightly occupied area mostly went unreported outside the seismological community.
Inevitably the readjustment has arrived at the eastern edge of the Pacific Plate and we seem to be seeing increased seismic events along that edge, which is also the western edge of the Americas.
Plate links to plate and the Pacific Plate connects to the Nazca Plate and Cocos Plates, which abut South America and link to the Caribbean Plate. The Pacific Plate forms the western side of the San Andreas fault along North America's west coast.
So, we have had major quakes in Haiti and Chile. Not too long ago there was a rare major quake on the Mid-Atlantic Ridge along a fault junction that connects to the Caribbean Plate.
Got that "Fall down, bounce around, shake the town, Earthquake Boogie!"
So, follow me on this; The Pacific Plate thrusts underneath the North American Plate angling towards the east as it dips deeper into the Earth. The magma chamber under Yellowstone sinks down towards the west. Prior to the recent determination of the scape of the Yellowstone Mama chamber it was assumed that the Yellowstone Supervolcano was a "hot spot" volcano similar to what we have here in Hawaii, but with the true scale and direction of the Yellowstone magma chamber currently understood, it seems more likely that Yellowstone is a classic subduction volcano.
But whether Yellowstone is directly connected to the subducting Pacific Plate or not, in geological terms they are in close proximity and Yellowstone's lava, like that of all exploding volcanoes, contains massive amounts of dissolved gasses like CO2.
Just as a sudden shock to a warm glass of soda pop will trigger an episode of increased fizzing, a major quake along the Pacific plate will send compression waves through the Earth and into the Yellowstone Magma Chamber and unbalance the current dynamic equilibrium of dissolved gasses. That might well trigger a significant eruption of Yellowstone.