A small explosion (possibly 20 meters tall) at El Hierro on Nov. 8, 2011. Image courtesy of St. Thomas Productions (http://www.saint-thomas.net/)

The activity at El Hierro has brought up a lot of questions about just exactly what happens when a volcanic eruption occurs underwater — and specifically, what happens if that eruption begins to occur in shallower water. This is the realm of “hydrovolcanism” or “phreatovolcanism” — when water and magma interact, either directly or indirectly, to produce volcanic activity.

A phreatic explosion on April 12, 1980 at Mount St. Helens. Image from the USGS.

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The monument to the Berkeley Free Speech Movement, decorated by Occupy Cal supporters after their eviction.

The Occupy movement took a turn for the symbolic in Berkeley this week, harkening back to a heritage of protest, social unrest, and progressive causes.

And, according to one former member of the Free Speech Movement, which began in the same spot, the implications of the Occupy movement could reverberate for a generation — even if the protesters only force small institutional changes.