2016-09-06. Scientists may have solved mystery of giant Midwest earthquakes.
By Elizabeth Deatrick, Science.
2014-10-14. Earth’s magnetic field could flip within a human lifetime.
2014-06-16. The Earth’s Hidden Ocean. Excerpt: An analysis of seismic waves passing through the deep earth appears to confirm what laboratory experiments have suggested was possible: that an ocean of water is tied up in the mantle, 400 miles below the surface. Any voyager to the center of the earth could leave the wet suit behind, however. The water is not liquid, but rather bound in minerals that exist at the extreme pressures found at such depths. ...“It’s a new view of the structure of this part of the earth,” said Brandon Schmandt, a geophysicist at the University of New Mexico and an author of a recent paper in the journal Science describing the research. The work also adds credence to the idea that the earth’s water accumulated in the interior during the planet’s formation, rather than arriving later through the bombardment of icy comets. In this view, water bound up in minerals in the mantle, the 1,800-mile-thick layer between the thin crust and the hot metallic core, degassed over time and reached the surface. The scientists studied a part of the mantle called the transition zone, from about 300 to 440 miles deep. The ability of this zone to contain water — and apparently to retain a lot of it — “may have something to do with stabilizing or buffering the size of the oceans,” said Steven D. Jacobsen, a mineralogist at Northwestern University and another author of the paper. “It may be fortunate that the earth’s interior can act like a sponge.” ...it’s not as if there are huge chambers of magma hundreds of miles below the surface, Dr. Jacobsen said. The melting occurs on the boundaries of the mineral grains. “You end up having a mushy rock,” he said. http://www.nytimes.com/2014/06/17/science/the-earths-hidden-ocean.html. By Henry Fountain.
2012 May 28. Earth's Core - The Enigma 1,800 Miles Below Us. By Natalie Angier, The NY Times. Excerpt: Geologists have long known that Earth’s core, some 1,800 miles beneath our feet, is a dense, chemically doped ball of iron roughly the size of Mars and every bit as alien… Researchers have also known that the core’s heat helps animate the giant jigsaw puzzle of tectonic plates floating far above it, to build up mountains and gouge out seabeds. At the same time, the jostling of core iron generates Earth’s magnetic field. Now it turns out that existing models of the core, for all their drama, may not be dramatic enough. Dario Alfè of University College London and his colleagues presented evidence that iron in the outer layers of the core is frittering away heat through the wasteful process called conduction at two to three times the rate of previous estimates. The theoretical consequences of this discrepancy are far-reaching. The scientists say something else must be going on in Earth’s depths to account for the missing thermal energy in their calculations….
2010 September. What's Really Shaking. By Kathleen M. Wong, Science Matters @ Berkeley. Excerpt:
...Many types of phenomena, from the shudders of a glacier to the
detonation of a nuclear bomb, can move mountains and get entire regions
Berkeley professor of earth and planetary science Douglas Dreger
analyzes the seismic signatures left behind by these and other exotic,
earthquake-like events. His work is aiding fields as diverse as
glaciology, mine rescues, and nuclear treaty enforcement.
Dreger takes full advantage of the data from modern digital broadband
seismometers…. Dreger filters such digital seismograms to reveal far
more than shaking magnitude. Using a technique called moment tensor
inversion, he can distinguish true earthquakes from mine implosions,
volcanic eruptions, and nuclear tests.
2010 May. Bobbing for Carbon. By Kathleen M. Wong. ScienceMatters, Berkeley. Excerpt:
…Think your garden is green? The blue waters of the oceans are actually
much greener. Every year, microscopic marine plants called
phytoplankton convert roughly 50 petagrams—50 trillion kilograms—of
carbon dissolved in ocean surface waters into living tissue. That’s half
of all the photosynthesis that occurs on the planet, and it happens at
an astoundingly rapid pace.
…To overcome these hurdles, Bishop has developed a fully autonomous
phytoplankton sampling robot. Dubbed the Carbon Explorer, it is designed
to rise to the surface and sink back down to 1,000 meters, sampling
plankton and ocean conditions all the way. Bishop’s robots cost about
$30,000 each, the equivalent of operating a research vessel for a single
day, yet can continue gathering data twice a day in absence of ships
for over a year. And they are tough. One operated in the ice surrounding
Antarctica for an entire winter, transmitting data to shore weekly and
emerging unscathed in spring.
2006 November 13. THE DARKENING SEA. By ELIZABETH KOLBERT, "The New Yorker" Issue
of 2006-11-20. What carbon emissions are doing to the ocean. ...In the
nineteen-nineties, researchers ... collected more than seventy thousand
seawater samples ... analysis of ...which was completed in 2004, ...
nearly half of all the carbon dioxide that humans have emitted ...has
been absorbed by the sea. ...carbonic acid ...can change the water's pH.
Already, humans have pumped enough carbon into the oceans...to produce a
.1 decline in surface pH. Since pH ... is a logarithmic measure, a .1
drop represents a rise in acidity of about thirty per cent. The process
is ... "ocean acidification," ... term coined in 2003 by two climate
scientists, Ken Caldeira and Michael Wickett, ...at the Lawrence
Livermore National Laboratory. ...Caldeira ...to brief some members of
Congress... was asked, 'What is the appropriate stabilization target for
atmospheric CO2?' " ... "And I said, 'Well, I think it's inappropriate
to think in terms of stabilization targets. I think we should think in
terms of emissions targets.' And they said, 'O.K., what's the
appropriate emissions target?' And I said, 'Zero.' "If you're talking
about mugging little old ladies, you don't say, 'What's our target for
the rate of mugging little old ladies?' You say, 'Mugging little old
ladies is bad, and we're going to try to eliminate it.' ...Coral reefs
are under threat.... When water temperatures rise too high, corals
lose...the algae that nourish them. (The process is called "bleaching,"
because without their zooxanthellae corals appear white.) ...The seas
have a built-in buffering capacity: if the water's pH starts to drop,
shells and shell fragments that have been deposited on the ocean floor
begin to dissolve, pushing the pH back up again. This buffering
mechanism is highly effective, provided that acidification takes place
on the same timescale as deep-ocean circulation. (One complete exchange
of surface and bottom water takes thousands of years.) ...Currently, CO2
is being released into the air at least three times and perhaps as much
as thirty times as quickly ...so fast that buffering by ocean sediments
is not even a factor....
2005 November 23. HOW DOES RADIOACTIVE DECAY WORK?, Teaching Quantitative Skills in the Geosciences, Jennifer M. Wenner, University of Wisconsin-Oshkosh, SERC, The
concepts of spontaneous decay, isotopes, and half-lives are discussed
as well as how geoscientists make use of radioactive decay in dating
beds and deposits. This page is paired with another which tackles the
mathematical issues behind exponential growth and decay equations to
allow educators to teach both the abstract concept and the concrete
2005 February. The Virtual Physics Lab session
is about the particle model of matter and looks at examples of the
behavior of matter on a macroscopic level that are best explained by
assuming matter was made of particles.
2005 February. USGS Animation of recent earthquakes worldwide
4 October 2004. EARTHQUAKE
FORECAST PROGRAM HAS AMAZING SUCCESS RATE.
NASA news. A NASA
funded earthquake prediction program has an
amazing track record. Published in 2002, the
Rundle-Tiampo Forecast has accurately predicted
the locations of 15 of California's 16 largest
earthquakes this decade, including last week's
December 2003. A
Mission to the Earth's Core, by John G.
Alternate View Column, published in Analog
Science Fiction & Fact Magazine. Adventure
stories involving the exploration of the interior
of Planet Earth have a long and distinguished
history in science fiction. Jules Verne's
Journey to the Center of the Earth (1864)
was perhaps the first such tale. ...Following
Verne's lead and doing considerably more violence
to geology, paleontology, and physics, Edgar
Rice Burroughs wrote seven novels beginning
with At the Earth's Core (1922) that were
set in Pellucidar, a "land" occupying
the inner surface of a vast spherical hole
in the Earth's hollow interior.... David Stevenson,
a Professor of Planetary Science at CalTech,
has proposed mounting an ambitious NASA-style
mission to the Earth's core. He describes
his "modest proposal" (in the Swiftian
sense) in a paper recently published in the
journal Nature. ... He proposes to use a multi-megaton
nuclear weapon and one hour's worth of the
net iron production of the Earth's iron smelter
facilities (~10^8 kg). The annotated paper,
A Modest Proposal: Mission to Earth's Core,
is at http://www.gps.caltech.edu/faculty/stevenson/coremission/
2003 to Present
Earthquake animation site at USGS
Deep Carbon Observatory