At 11:37 pm on August 17, 1959, a magnitude 7.5 earthquake struck near Yellowstone Park. At the time, there were two geologists from the United States Geological Survey who were doing fieldwork in the area, and who were living in a camping trailer near the epicenter. The earthquake had a strong impact on how each of the two thought about their field, about how the earth operates, and about the longrunning geophilosophical debate between the uniformitarians and the catastrophists.
If you spend any time doing geology, you hear something about uniformitarianism and catastrophism. Uniformitarianism, we are usually told, basically means that the earth functions now more or less the way it always has. Catastrophism, by contrast, is the belief that the history of the earth has been shaped by a series of catastrophic events. The conventional wisdom holds that uniformitarianism kicked catastrophism's ass back in the mid-nineteenth century, but the catastrophists began staging a bit of a comeback in the 1980s, as we began to better understand the role of big flying rocks in the history of life.
Back in the late 1990s, I spent a couple of years working as a contract lab tech at the US Geological Survey's headquarters in Reston, Virginia. The USGS has a spectacularly good library there, and I've always been interested in history, so I spent quite a bit of time down in the basement reading through Victorian-era books and journals. Somewhere along the way I developed a particular interest in uniformitarianism and catastrophism, and I started to wonder what opinions - if any - the geologists on my team had on the topic. So I wandered around the halls and asked quite a few. As luck would have it, both of the geologists who were sitting in the camp trailer when the 1959 quake hit were still hanging around.
One of the geologists in question was Anita Harris. The views she expressed to me were (unsurprisingly enough) very similar to what she told John McPhee, when he traveled with her for his book In Suspect Terrain:
As the night returned to quiet and the ground ceased to move, Anita recovered whatever composure she had lost, picked up her deck of cards, and said to herself, "That's the way it goes, folks. The earth's a very shaky mobile thing, and that's how it works. Apparently, the mountains around here are still going up. Later, she would say, "We were taught all wrong. We were taught that changes on the face of the earth come in a slow steady march. But that isn't what happens. The slow steady march of geologic time is punctuated with catastrophes. And wat we see in the geologic record are the catastrophes. Look at a graded sandstone and see the bedding go from fine to coarse. That's a storm. That's one storm - when the water came up and laid the course material down over the fine. In the rock record, the tranquility of time is not well represented. Instead, you have the catastrophes. In the Southwest, they live from one catastrophe to another, from one flash flood to the next. The evolution of the world does not happen a grain at a time. It happens in the hundred-year storm, the hundred-year flood. Those things do it all. That earthquake made a catastrophist of me."
The earthquake made a catastrophist of Anita. But for her then-husband Jack Epstein, it reinforced his understanding of uniformitarianism. I don't have John McPhee's skills as a writer, and I didn't take great notes when I talked to Jack. But the ones I did take are more than enough to refresh my memory of what he told me.
When I asked him about uniformitarianism, he told me about the earthquake. That earthquake, Jack told me, is uniformitarianism in action. It's a big event to us, but not to the planet. The mountains, Jack pointed out, are the result of no one earthquake. They're the product of earthquakes and storms, some pushing up, some washing down, over huge periods of time.
One earthquake. Two geologists. The earthquake makes a catastrophist of one, and confirms the uniformitarianism of the other. What does that tell the rest of us?