The intensity of earth's magnetic field has been weakening in the last couple of hundred years, leading some to claim that its polarity might be about to flip.

But the field's intensity is coming down from an abnormal high rather than approaching a reversal. And despite Doomsday prophecies stating otherwise, humans have lived through dips in the field's intensity before. Linking reversals in the more distant past to species extinctions is just speculation that can't be proved or disproved, which makes them ideal fodder for scary stories about nature.

Researchers have attempted to measure all the material leaving and entering a mountain range over millions of years and discovered that glacial erosion can, under the right circumstances, wear down mountains faster than plate tectonics can build them.

A study of the St. Elias Mountains on the Alaskan coast by researchers from The University of Texas at Austin, University of Florida, Oregon State University and elsewhere found that erosion accelerated sharply about one million years ago.

Oklahoma is in the news a lot for earthquakes because of activist claims about hydraulic fracturing, the modern process of natural gas extraction.

In reality, the earthquakes may be linked to conventional drilling but the numbers are nothing out of the ordinary - and those are nothing compared to just southern California, which has 30 every day. That's due to the San Andreas Fault system.

Cities that line the fault, like Los Angeles and San Francisco, have been fortunate for the last 100 years - there hasn't been a major destructive earthquake of magnitude 7.5 or more -- but it's coming. Large earthquakes occur at about 150-year intervals on the San Andreas, so the next 'big one' is near.

Scientists have nearly completed the first map of the mantle under the tectonic plate that is colliding with the Pacific Northwest and putting Seattle, Portland and Vancouver at risk of the largest earthquakes and tsunamis in the world.

The new report describes how the movement of the ocean-bottom Juan de Fuca plate is connected to the flow of the mantle 150 kilometers (100 miles) underground, which could help seismologists understand the forces generating quakes as large as the destructive Tohoku quake that struck Japan in 2011 and led to the tsunami that caused the issues at the Fukushima nuclear plant.

The Cascadia subduction zone (CSZ) has captured major attention from paleoseismologists due to evidence from several large (magnitude 8-9) earthquakes preserved in coastal salt marshes. Stratigraphic records are proving to be useful for learning about the CSZ's past, and microfossils may provide more answers about large ancient earthquakes.

They may also allow modelers to learn more about potential major hazards related to earthquakes in the area, which would contribute to public preparedness for such events.

By meticulously examining sediments in China's Yellow River, a Swedish-Chinese research group are showing that the history of tectonic and climate evolution on Earth may need to be rewritten. Their findings are published today in the highly reputed journal Nature Communications.

To reconstruct how the global climate and topography of the Earth's surface have developed over millions of years, deposits of eroded land sediment transported by rivers to ocean depths are often used. This process is assumed to have been rapid and, by the same token, not to have resulted in any major storages of this sediment as large deposits along the way.

In the Mediterranean climate of California, with its warm, wet winters and hot, dry summers, the snowpack in the Sierra Nevada mountains plays a critical role. It serves as a natural water storage system that feeds waterways and reservoirs during the dry summer months.

That’s why it was very fitting that when Governor Jerry Brown announced the first-ever mandatory statewide water restrictions, he did it from the snow-barren Phillips snow course station in the Sierra Nevada. The April 1 snowpack’s water content has been measured at this station since 1941 and has averaged at 66.5 inches over this period.

We can be concerned about erosion due to man-made causes but it is nothing like what nature will randomly do in a single year, without ever once consulting Natural Resources Defense Council or other industry-funded groups.

The historic September 2013 storm that triggered widespread flooding across Colorado's Front Range eroded the equivalent of hundreds, or even as much as 1,000 years worth of accumulated sediment from the foothills west of Boulder, researchers at the University of Colorado Boulder have discovered. The findings in Geology suggest that erosion may not always be a slow and steady process, like due to housing or shifts in vegetation, but rather can occur in sudden, rapid bursts due to extreme weather events such as hundred- and thousand-year storms.

In 1884, a delegation of international representatives convened in Washington, D.C. to recommend that Earth's prime meridian (the north-south line marking zero degrees longitude) should pass through the Airy Transit Circle at the Royal Observatory in Greenwich, England.

(A transit circle is an instrument for measuring star positions, and could be used for determining local time; this one was named for its designer, British Astronomer Royal George Airy.)