David Ritchie, Alexander E. Gates, "Encyclopedia of Earthquakes and Volcanoes"
From aa to Yellowstone, if it's got anything at all to do with earthquakes or volcanoes, you're likely to find within the pages of this updated encyclopedia from science journalist David Ritchie and Rutgers geology professor Alexander Gates.
The 1,000-plus alphabetical listings range from historical volcanoes and quakes (both famous and obscure) to entries on specific seismic phenomena (everything from parasitic cones to jökulhlaup) and general geological principles, including a few excellent in-depth discussions on topics like plate tectonics and seismic wave types. The encyclopedia also contains a lengthy bibliography, a list of Internet resources, a chronological listing of notable quakes and eruptions, and a handful of unforgettable eyewitness accounts (after the eruption of Vesuvius in A.D. 79, apparently Pliny the Elder's party went out "having pillows tied upon their heads with napkins; and this was their whole defense against the storm of stones that fell around them").
With its clear, newspaper-style entries, the Encyclopedia of Earthquakes and Volcanoes will be navigable even to geo-newbies, but its a-to-z organization makes it more useful as a reference than as a stand-alone text.