Friday Headlines : 9-26-14

Friday Headlines, September 24, 2014

THE LATEST IN THE GEOSCIENCES

 

Today’s round-up:

Ice worms?! Eww!

The Earth’s magnetic poles could flip?!

What next? An earthquake? YES!

 

Glacier Ice Worms in Action

Ok. I’m just putting this here because I didn’t even know there were worms living in the ice on the surface of glaciers.

See more on the article site.

 

Earth’s Impending Magnetic Flip

My initial reaction to this is that it’s the regularly-occurring hype about the Earth’s magnetic field decreasing in intensity, something that I’ve known about for a long time.

This is slightly newer and a bit different.

The Earth’s magnetic field, if considered to be like a simple bar magnet aligned with the planet’s rotation axis, has been known to flip North pole with South pole many times in Earth’s history. There is usually a decrease in the strength or intensity of the magnetic field leading up to a flip. It’s thought that these reversals tend to take around 2000 years, but can be as fast at 1000 or as slow as 20,000 years.

New research shows still that the Earth’s magnetic field is currently decreasing in its intensity at a faster rate than initially thought, meaning that if a reversal or flip is on its way, we might see a change in the next 1000 years.

It’s possible that the decrease in intensity is not going to end in a flip. There have been many episodes where flips started, and the intensity of the magnetic field was lost, but where the magnetic poles remained the same when the intensity returned.

Understanding why this is and how the magnetic field flips is a key area in geophysical research currently. We do not as yet fully understand how the magnetic field even forms in the Earth. We must understand this before we can understand what causes it to lose intensity and flip.

 

M6.2 – 95km WNW of Willow, Alaska

…Because geologic calamity always makes me happy.

Luckily, there was not significant damage from this earthquake. A magnitude 6.2 in an area equipped to deal with earthquakes is relatively minor.

But there was an earthquake in Alaska this morning. And I need some tectonics to round out my headlines for the day.

The earthquakes in Alaska and along the Aleutian Island chain (in fact the islands themselves) are due to the Pacific Plate, which underlies the Pacific Ocean, slipping under the North American Plate which is called Alaska right there.

The Aleutian Islands, showing how the Pacific Plate is moving below them. Credit: USGS
The Aleutian Islands, showing how the Pacific Plate is moving below them. Different colors indicate the depth to the surface of the Pacific Plate that is now fully underneath the North American plate. Credit: USGS

Friction between the Pacific Plate and the North American Plate is what causes the abundant earthquakes in Alaska.

A subduction zone. In the case of Alaska, the Pacific Plate is on the left being subducted below the North American Plate on the right. Credit: USGS

This particular earthquake was close to and felt in Anchorage near the eastern termination of the Aleutian Trench.

Intensity of the 6.2 magnitude quake near Anchorage. Cool colors indicate low intensity of shaking. Credit: USGS
Intensity of the 6.2 magnitude quake near Anchorage. Cool colors indicate low intensity of shaking. Credit: USGS

While this earthquake was relatively mild, it is part of the larger complexity of plate tectonics and the ‘Ring-of-Fire’ that encircles the Pacific Ocean.

Pacific Ring of Fire.svg
The Ring of Fire! “Pacific Ring of Fire” by Gringer (talk) 23:52, 10 February 2009 (UTC) – vector data from [1]. Licensed under Public domain via Wikimedia Commons.

Published by paleololigo

Scientist (Paleontology, Geochemistry, Geology); Writer (Speculative and Science Fiction, plus technical and non-technical Science); Mom to great boy on the Autism spectrum; possessor of too many hobbies.

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