The life and times of volcanoes, earthquakes, crustal bumps and grinds are told with wit and style by newsman and magazine writer David Ritchie. Following Mt. St. Helens' blastoff, one might have expected a fallout of popular geologies. Apparently not. So it's pleasant to report that if this is it, for the moment, it's a dandy--abrim with eye-catching references to, for instance, lava that billowed out in ""great dark-gray rounded formations like a frozen cascade of discolored shaving cream."" The setting of the Cascades and Mt. St. Helens provides the lead and the tie-in to the title: the volcanic chain in the northwest is but one sector of a narrow band of intense earthquake and volcanic activity--the Ring of Fire--that stretches from Tierra del Fuego to the Aleutians. The ring follows the eastern Pacific coast and then curves around to Kamchatka and south to Japan, eastern China, Indonesia, the Philippines, and New Zealand. There are other foci, too, in the Middle East, the mid-Mediterranean, and north India, for example. Ritchie discusses the theory and evidence for earth's geological changes and provides vivid accounts of some of the major upheavals: Krakatoa, Tsunamis off Japan, and some manmade events--it's possible that Russian underground nuclear explosions triggered the 1978 Iranian earthquake. There are biographical sketches of celebrities like Alfred Wegener, who, we learn, died of a heart attack while trekking across Greenland, whose icy mountains he adored. Also on tap: the potential of geological warfare; popular superstitions; questions about the predictability of quakes; and what we can learn about earth's origins and sources of energy by studying global ""hot spots."" You may not think you care all that much about plate tectonics and mid-ocean ridges--or John McPhee's Basin and Range may have started your conversion. Credit Ritchie's skills as a writer that he, like McPhee, makes you care.