In the early 1900s, debate raged about Southern California’s earthquake risk. Intrigued by the adversaries, seismologist Susan Hough wrote a book about it.
By Alka Tripathy-Lang, Ph.D (@DrAlkaTrip)
Citation Tripathy-Lang, Alka, (2020), The Great Quake Debate: an interview with seismologist and author Susan Hough, Temblor, http://doi.org/10.32858/temblor.115
Growing up a self-proclaimed “geeky kid” whose hobbies were reading, writing and arithmetic, Susan Hough always had a penchant for the “writing” part, penning poems, stories or even comic strips in her spare time. She spent her childhood shuttling around North America because of her academic father, but landed in earthquake country for her undergraduate degree at the University of California Berkeley. Originally planning to major in math, astronomy or computer science, she ended up taking geophysics courses. She found the mathematically focused discipline appealing for its real-world relevance, and went on to obtain her Ph.D. from the Scripps Institution of Oceanography in San Diego. After a four-year stint at Lamont-Doherty Geological Observatory in New York, she returned to California as a seismologist for the U.S. Geological Survey (USGS), where she continues to research myriad topics in earthquake science for her day job, while writing books and doting on her grandsons in her spare time.
In her latest book, The Great Quake Debate, published July 23, 2020, Hough introduces us to the two men on either side of an important scientific and societal question in the early 1900s. On one side stood geologist Bailey Willis, described as the charismatic crusader who prophesied a big earthquake in Southern California. Leading the other side was fellow geologist Robert T. Hill, described as the ornery skeptic who decried Willis’ bold claim. With the benefit of hindsight, we know that Willis’ prediction rested on erroneous calculations. Of course, on the larger question of whether Los Angeles faced significant earthquake hazard, we now know Willis was right. Back then, however, the question of Southern California’s seismic hazard loomed large for scientists, businesses and citizens of the greater Los Angeles area, as well as those who wanted to migrate to the bustling oil town.
In our conversation, which has been edited for length and clarity, Hough shares her thoughts on this, her sixth, book, her inspirations, and how the two main characters’ lessons transpose onto modern problems — climate change and COVID among them.
Alka Tripathy-Lang (AT): What inspired you to write this book?
Susan Hough (SH): I was doing research on the 1925 Santa Barbara earthquake [which played a pivotal role in the debate]. I went to the Huntington Library to read Bailey Willis’ papers because he was on the spot when that earthquake happened. It occurred to me that he was one of these interesting individuals in science about whom not much had been written.
I was also aware, although I had never thought much about it, that there were different takes on [Hill’s role] in the central debate. There’s the classic take that Hill was in the back pocket of the business community. Then there’s another take that he was completely set up by local city boosters. I wondered what the real story was.
As I started looking into both Hill and Willis, I realized how interesting their lives were individually, but also how oddly parallel their lives were. They were born around the same time, worked at the USGS during the agency’s early years, and had a long history together as colleagues and rivals. The more I poked into it, the more interesting the story became.
AT: Tell me a little bit about Hill and Willis. How do you relate to them?
SH: When you dive into both of their childhoods, they both emerge as sympathetic characters. What Hill went through as a very young child, with his family torn apart by the Civil War, and then later on the Texas frontier … to have risen above that and made his way to Cornell is pretty remarkable. Willis was more privileged, growing up as the apple of his mother’s eye. Nevertheless, he lost his father at a young age and never had a father figure in his life.
Writing about historical figures is really interesting because you can start to relate to what people went through and how they reacted. Willis made a prediction that was fundamentally unfounded. It got people’s attention, but in my view, he stepped over a line that scientists shouldn’t cross. I definitely relate more to Hill, the one who [I imagine] said, “No, that prediction isn’t based on sound science, you can’t say that.” If you’re going to divide scientists into skeptics or crusaders, I’m definitely cut from the skeptic mold.
AT: The book is full of other secondary, yet important, characters. Who else made a substantial impact on the debate?
SH: There was this guy, Ralph Arnold, who was an interesting character. He was a geologist who went into the oil industry and got quite wealthy. But he was very well-connected politically and very influential — the ultimate politician. He illustrates how big of a role people can have behind the scenes. You have the ones who can end up center stage and visible, but then there are the movers and shakers that you may have never heard of who influence what’s happening.
AT: As you point out in the book, it’s really hard to figure out what people’s underlying motivation was.
SH: You find these tidbits along the way. It’s often not immediately clear why people or organizations were doing what they were doing, what their interests were. I looked not just at what happened, but why it happened. What were the driving forces and motivations at play? You don’t always find all the answers, but I was very fortunate to have extremely good archival material that helped me put a lot of puzzle pieces together.
AT: What are some lessons from the book?
SH: One of the lessons is underscoring the challenges of science communication. In any developing field, you have scientists trying to sort things out. The knowledge isn’t perfect. There are debates; there are points of agreement. There are messages that are important for the public to hear.
How that communication plays out was challenging then, and is challenging now. There’s a vanishingly fine line with effective science communication when you are dealing with potential mortal peril. You want to get people’s attention. You want them to take it seriously. But you have to avoid stepping over that line, into hype, at which point you’re crying wolf and people tune you out. It’s as tough today as it was back then.
But, in the end, things do move forward in a messy, imperfect way. There are actual truths in science. Some things aren’t debatable. And in earthquake science, earthquakes come along and settle the score. This remains true today. For example, there’s debate now about how strongly the ground will shake in Los Angeles when we have an earthquake like the 1857 Fort Tejon event, and how modern tall buildings will respond. Eventually, we’re going to see a big earthquake come to the southern San Andreas, and we’re going to find out. Hopefully we’ve got the building codes right and it won’t be a huge disaster.
Another lesson is that although there are debates in science, there is a body of knowledge — a body of agreement. If you look carefully at what Hill and Willis were saying, they were both saying that risk mitigation was important and buildings needed to be built properly. They both knew there are faults and earthquakes in California. They were debating the details.
AT: How do you think the book is relevant considering the perils we are currently facing, like COVID-19 and climate change?
SH: Today, there are unknowns about the [novel] coronavirus, but there’s still a fundamental body of knowledge that points us in a certain direction. We need to focus on that in terms of public messaging. We have to communicate what we don’t know, but also what we do know.
Another lesson of The Great Quake Debate is that there can be more going on behind the scenes than might be obvious to the public. I don’t want to give away too much of the story, but my research taught me that business leaders and civic boosters back then weren’t stupid people. Anyone who lived, worked or owned property in Los Angeles in the early 20th century had to care about earthquakes. They saw headlines about the huge disaster that played out after a 1923 earthquake near Kanto, Japan. In the face of today’s new perils, regardless of business owners’ political leanings, they have to care about the health and safety of their employees and their customers. And so some big companies are requiring that masks be worn inside their stores, even if political leadership is taking a stand against mask requirements.
When it comes to natural hazards — everything from earthquakes to biological pathogens — there’s a common ground dictated by science, not politics, that we all want to find.
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