<http://schema.org/alternativeHeadline>
"The size of released volcanic particles depends on how deep eruptions originate and how often rocks run into each other on their way out."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/earth-matters/wilderness-resources/stories/why-all-volcanic-eruptions-are-not-created-equal>