HOW DID WE FIND OUT ABOUT EARTHQUAKES?

As in his other How Did We Find Out books, Asimov begins with the beliefs of primitives and ancients; later come summaries of other theories that "didn't work out" either, plus a synopsis of landmarks in the development and application of the seismograph. As earthquakes can't be considered today without reference to plate tectonics, Asimov starts that story with Wegener's continental drift theory, touches on the evidence from the seafloor, and—with a diagram showing where the plates line up today—concludes that most earthquakes take place on the cracks between them. With a stretched-out discussion of whether people should "leave" (evacuate) on the mere possibility of a quake, this is one of the flimsier entries in Asimov's history-oriented series. Readers will come away from Fodor's Earth in Motion (p. 638, J-154), about plate tectonics, with a better understanding of earthquakes than they get here; for a fuller all-around discussion of the subject, see Lauber's Earthquakes (1972).