21 May 2023

I’ve come to the end of my run of reading John Dvorak’s geology books. This is the fourth one for me to consume, but it was apparently the first he wrote. The topic is earthquakes, specifically those that occur along the San Andreas Fault in California. I’ve read a fair bit, it feels like, about the San Andreas: Carl-Henry Geschwind’s history, Susan Hough’s books, and just yesterday I started Andrew Alden’s Deep Oakland, in which the San Andreas’s eastern neighbor the Hayward Fault takes the central role, but the San Andreas plays a supporting role. Dvorak’s book is overall an approachable summary of the geology and the geologists who figured out what we know about it. Andrew Lawson, Charles Richter, Kerry Sieh, and Tanya Atwater all have important contributions, and Dvorak tells their stories well, so far as I can tell. What gave me a bit of pause was that there’s one or two paragraphs about east coast geology offered in a sort of “compare and contrast” section, and I found much wrong there – both typos and what I would argue are errors of emphasis. The former were at least were obvious and plain, and should have been caught prior to publication. It shook my confidence in the rest of the book. Dvorak structures the book so that the big culmination is the idea of centuries-long “earthquake storms:” a series of big shocks and aftershocks as stress is transferred along a major fault and its neighbors and subsidiaries. The notorious sequence from 1939 to 1999 along the North Anatolian Fault in Turkey is cited as an example of this “storm” phenomenon, and it’s what Dvorak expects when the southern stretch of the San Andreas finally ruptures after so many years of accumulating tectonic stress. Not “the big one,” therefore; he’s expecting “some big ones.” An interesting take, and all too plausible. I’m very grateful that I got to see the southern portion of the San Andreas in person just a few months ago; it made reading Earthquake Storms feel more urgent and vital.