How can scientists best talk about the risks of natural hazards with the general public? And how can a lay reader assess debates among scientists? Susan Hough offers useful tips for both, drawing on her new book, The Great Quake Debate: The Crusader, the Skeptic, and the Rise of Modern Seismology.

Through spring of 2020, the publication process moved forward apace for The Great Quake Debate. In a sense, it might be considered a coming of age story, focusing on the chapter in time when a major metropolitan region, Los Angeles, first came to grips with a seemingly existential peril: earthquake hazard. Could the rapidly growing city—one of the leading oil-producing regions in the world—really be hit by a massive earthquake like the one that had left San Francisco in ashes not too many years earlier? The Great Quake Debate is a story complete with (putative) heroes and villains, drama and intrigue.

It is also a story with lessons for our times, in particular now that the entire world struggles to come to grips with a different mortal peril. In the early 20^th century, many people had the luxury of viewing earthquake hazard as somebody else’s problem. Later science would prove them only partly right, but, indeed, earthquakes pose a real and present dangerin some places than in others. Microbes, on the other hand, do not concentrate along narrow fault lines. Potentially they reach us all. The realization dawns, that some of the lessons of The Great Quake Debate are especially relevant for our tumultuous times, including lessons for both scientists and the public regarding the business of science communication. Let me pull out five of them, three for consumers of scientific information, and two for those who disseminate it.

1. If you want information, go to the source. As directly as possible, go to the source. When parts of The Great Quake Debate have been told before, renowned geologist Robert T. Hill has been painted as the villain, a “tool” used by local city boosters to advance their agenda. A generally well-researched earlier biography focused on the extent to which Hill was manipulated by city boosters, describing him as a victim of their machinations. The personal papers that he and others left behind tell a far more nuanced, complex story.
2. When you are looking for scientific information, know that science has limitations. There are truths in science, and as the saying goes, science doesn’t care what you believe. But in a rapidly developing field, science can be messy. The answers might not be black-and-white, and even well-respected scientists can be wrong. In his crusade to convince the public to take earthquake hazard seriously, in 1926 protagonist Bailey Willis made public statements that southern California would likely be wrenched by a great earthquake within three to 10 years of 1926. Although many saw the 1933 Long Beach earthquake as vindication of Willis’ prophesy, the magnitude-6.4 earthquake was not the major temblor that he had predicted. Hill’s refutation of the prediction, on the other hand, drew from sound science.
3. Listen to scientists. Wait, what? Why should anyone listen to scientists, if they might themselves be wrong? The thing is, scientists might not be right, but at any given time, their understanding is as good as it gets. Had people listened carefully to either Willis or Hill, they would have heard a debate on some key questions, but also very similar messages from both, delivered with no small degree of passion, regarding the importance of understanding earthquake hazard and taking steps to reduce earthquake risk.
4. For those of us who are ourselves scientists, beware the perils of over-stepping what science allows us to say. Willis based his prediction on analysis of early surveying data that he should have known to be highly uncertain. Hill correctly debunked the prediction, but did make statements downplaying the severity of earthquake hazard in Los Angeles. His reassuring statements, while never dismissing hazard entirely, were based on some misperceptions of his day, for example concerning the potential severity of shaking caused by moderately large earthquakes. He, too, should have known that such statements were not well-supported by available data. The media may have amplified the message, but scientists themselves set the tone. Where science collides with public welfare and public fears, missteps in one direction can assuage fears, while missteps in the other direction can fan flames. Neither serves the public good.
5. Sooner or later, the natural world will have the last word. Scientists can debate the severity of the perils that we face, and the need to take risk mitigation seriously. People and policy-makers can choose to heed warnings, or not. Depending on the nature of the risk, it can be expensive to heed warnings, or personally uncomfortable, or inconvenient. If worst fears are borne out, what will you wish you had done yesterday? Do it today.

Susan Hough is a research seismologist in Pasadena, California. Her popular-science books include Earthshaking Science: What We Know (and Don’t Know) about Earthquakes and Richter’s Scale: Measure of an Earthquake, Measure of a Man. Her latest book The Great Quake Debate: The Crusader, the Skeptic, and the Rise of Modern Seismology is available now.