Yellowstone – Behind The Black

Largest quake in Yellowstone since 2014

June 19, 2017 10:03 am Robert Zimmerman

The USGS today recorded a magnitude 4.5 earthquake at Yellowstone today, the largest since a magnitude 4.8 occurred in March 2014, and part of a continuing swarming of small quakes that began on June 12.

This sequence has included approximately thirty earthquakes of magnitude 2 and larger and four earthquakes of magnitude 3 and larger, including today’s magnitude 4.5 event.

It is hard to say whether this swarm of small quakes portend a really big volcanic event, or will simply die off in the coming days. Recent data at Yellowstone has suggested the former is possible, though not imminent.

One comment

Grizzly bear no longer endangered in Yellowstone

November 3, 2015 4:57 pm Robert Zimmerman

Good news! Federal wildlife officials have determined that the grizzly bear population in and around Yellowstone has recovered so well that they have the option of removing the species from the endangered species list.

The latest count of grizzlies in the Yellowstone region puts the estimated population of the hump-shouldered bruins at just over 750, well exceeding the government’s recovery goal of 500 animals, according to the U.S. Fish and Wildlife Service. That compares with just 136 believed left in the Yellowstone ecosystem – encompassing parts of Wyoming, Montana and Idaho – when grizzlies were formally listed as threatened throughout the Lower 48 states in 1975, after they were hunted, trapped and poisoned to near extinction.

Not surprisingly, the article notes how environmental and American Indian groups oppose changing the bear’s status. Want to bet that they win the day and the bear remains endangered? Science really has very little to do with the endangered species act these days. It is all politics.

2 comments

Seismic data of Yellowstone has found a bigger second magma chamber

April 24, 2015 9:52 am Robert Zimmerman

Geologists have mapped the existence of a second deeper and larger magma chamber under Yellowstone National Park.

Scientists had already known about a plume, which brings molten rock up from deep in the mantle to a region about 60 kilometers below the surface. And they had also imaged a shallow magma chamber about 10 kilometers below the surface, containing about 10,000 cubic kilometers of molten material. But now they have found a deeper one, 4.5 times larger, that sits between 20 and 50 kilometers below the surface. “They found the missing link between the mantle plume and the shallow magma chamber,” says Peter Cervelli, a geophysicist in Anchorage, Alaska, who works at the U.S. Geological Survey’s Yellowstone Volcano Observatory.

The discovery does not, on its own, increase the chance of an eruption, which is driven by an emptying of the shallow chamber. The last major eruption was 640,000 years ago, and today the threat of earthquakes is far more likely. But the deeper chamber does mean that the shallow chamber can be replenished again and again. “Knowing that you have this additional reservoir tells you you could have a much bigger volume erupt over a relatively short time scale,” says co-author Victor Tsai, a geophysicist at the California Institute of Technology in Pasadena. The discovery, reported online today in Science, also confirms a long-suspected model for some volcanoes, in which a deep chamber of melted basalt, a dense iron- and magnesium-rich rock, feeds a shallower chamber containing a melted, lighter silicon-rich rock called a rhyolite.

To environmentalists no warming and more bears means global warming and an endangered species

January 22, 2014 9:20 am Robert Zimmerman

A U.S. Geological Survey science team has determined that the grizzly bear population has recovered enough that the bear can be taken off the endangered species list.

A report delivered in November by the US Geological Survey’s Interagency Grizzly Bear Study Team describes a resilient and healthy bear population that has adapted to the loss of pine nuts by eating more elk and bison, keeping fat stores at levels that allow the bears to survive and reproduce. For Christopher Servheen, a biologist who oversees grizzly-bear recovery efforts at the Fish and Wildlife Service in Missoula, Montana, that is not surprising. “Bears are flexible,” he says. “It’s easier to say what they don’t eat than what they do eat.”

Not surprisingly, environmental activists don’t like this decision. They claim that, wait for it, global warming threatens the bear enough that it should not be delisted.
» Read more

2 comments

Geologists have determined that the magma reservoir under Yellowstone is much bigger than previously thought.

October 29, 2013 9:25 am Robert Zimmerman

The uncertainty of science: Geologists have determined that the magma reservoir under Yellowstone is much bigger than previously thought.

Jamie Farrell, a postdoctoral researcher at the University of Utah, mapped the underlying magma reservoir by analysing data from more than 4,500 earthquakes. Seismic waves travel more slowly through molten rock than through solid rock, and seismometers can detect those changes.

The images show that the reservoir resembles a 4,000-cubic-kilometre underground sponge, with 6–8% of it filled with molten rock. It underlies most of the Yellowstone caldera and extends a little beyond it to the northeast.

The geologists also noted that the threat from a huge volcanic eruption is less of a concern than that of earthquakes.