John Dvorak
John Dvorak

John Dvorak, Ph.D., has worked on volcanoes and earthquakes for the U.S. Geological Survey.

April 21 2014 2:07 PMWill We Ever Be Able to Predict Earthquakes?Once, seismologists correctly predicted a major quake. They were only 12 years off on the timing.
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The History of American Slavery
Oct. 13 2015 3:34 PM How Did American Slavery End? History of American Slavery, Episode 9: The long process of emancipation.