Pole Shift Underway Earths spin and volcanic eruptions: evidence for mutual cause-and-effect interactions? The angular velocity of Earths rotation shows decadal oscillations due to the lunisolar gravitational torque, as well as inter- or intra-annual changes arising from the angular momentum exchange between the atmosphere and the solid Earth. The energies involved in the Length of Day (LOD) variations may affect the crustal deformation rate and seismic energy release on a global scale. Moreover, the injection of sulphur gases into the atmosphere during major eruptions is accompanied by significant inter-annual LOD variations. onlinelibrary.wiley/enhanced/doi/10.1111/ter.12073/ Eruptions Caused by Climate Change In recent decades, it has become apparent that the consequences of planetary ice loss might not end with rising sea levels. Evidence has been building that in the past, periods of severe loss of glaciers were followed by a significant spike in volcanic activity. Ice sheets are heavy. Each year, Antarctica’s loses around 40 billion metric tons. They are so heavy, in fact, that as they grow, they cause the Earth’s crust to bend – like a plank of wood when placed under weight. The corollary of this is that, when an ice sheet melts, and its mass is removed, the crust springs back. This upward flexing can lead to a drop in stress in the underlying rocks, which, the theory goes, makes it easier for magma to reach the surface and feed volcanic eruptions. blogs.discovermagazine/crux/2014/09/25/why-volcanic-eruptions-come-in-clusters/#.VCYXh_4gtDT Satellite Swarm Spots North Pole Drift The first high-definition measurements from Swarm have been made and what’s become apparent are weakening regions within the core-generated magnetic field over the western hemisphere, while parts of the southern Indian Ocean show strengthening fields. Swarm measurements also confirm the march of the magnetic north pole toward Russia. news.discovery/earth/satellite-swarm-spots-north-pole-drift-140622.htm Earths Inconstant Magnetic Field (And NASAs constant Flip-Flop -.-) Sometimes the field completely flips. The north and the south poles swap places. Such reversals, recorded in the magnetism of ancient rocks, are unpredictable. They come at irregular intervals averaging about 300,000 years; the last one was 780,000 years ago. Are we overdue for another? No one knows. To understand whats happening, says Glatzmaier, we have to take a trip ... to the center of the Earth where the magnetic field is produced. At the heart of our planet lies a solid iron ball, about as hot as the surface of the sun. Researchers call it the inner core. Its really a world within a world. The inner core is 70% as wide as the moon. It spins at its own rate, as much as 0.2o of longitude per year faster than the Earth above it, and it has its own ocean: a very deep layer of liquid iron known as the outer core. Earths magnetic field comes from this ocean of iron, which is an electrically conducting fluid in constant motion. Sitting atop the hot inner core, the liquid outer core seethes and roils like water in a pan on a hot stove. The outer core also has hurricanes--whirlpools powered by the Coriolis forces of Earths rotation. These complex motions generate our planets magnetism through a process called the dynamo effect. Using the equations of magnetohydrodynamics, a branch of physics dealing with conducting fluids and magnetic fields, Glatzmaier and colleague Paul Roberts have created a supercomputer model of Earths interior. Their software heats the inner core, stirs the metallic ocean above it, then calculates the resulting magnetic field. They run their code for hundreds of thousands of simulated years and watch what happens. What they see mimics the real Earth: The magnetic field waxes and wanes, poles drift and, occasionally, flip. Change is normal, theyve learned. And no wonder. The source of the field, the outer core, is itself seething, swirling, turbulent. Its chaotic down there, notes Glatzmaier. The changes we detect on our planets surface are a sign of that inner chaos. Theyve also learned what happens during a magnetic flip. Reversals take a few thousand years to complete, and during that time--contrary to popular belief--the magnetic field does not vanish. It just gets more complicated, says Glatzmaier. Magnetic lines of force near Earths surface become twisted and tangled, and magnetic poles pop up in unaccustomed places. A south magnetic pole might emerge over Africa, for instance, or a north pole over Tahiti. Weird. But its still a planetary magnetic field, and it still protects us from space radiation and solar storms. And, as a bonus, Tahiti could be a great place to see the Northern Lights. In such a time, Larry Newitts job would be different. Instead of shivering in Resolute Bay, he could enjoy the warm South Pacific, hopping from island to island, hunting for magnetic poles while auroras danced overhead. nasa.gov/vision/earth/lookingatearth/29dec_magneticfield.html Earths Magnetic Field Made Quick Flip-Flop Earths magnetic field reversed extremely rapidly soon after modern humans first arrived in Europe, completely flip-flopping in less than a thousand years, new research suggests. news.discovery/earth/weather-extreme-events/earth-magnetic-field-poles-flip-fast-121024.htm More Links: 50kview.blogspot.de/2014/03/april-01-2014-hmo-update-earth-pole.html
Posted on: Sat, 27 Sep 2014 02:57:59 +0000
Trending Topics
Recently Viewed Topics
© 2015