The Talk. Unlike many regions in the country, the Seattle area is constantly reminded of its geologic past, present, and future. Whether it is our landslides, our glacier-carved topography, or our volatile volcanoes, this area’s geologic history is young, dynamic, and accessible. In this talk, I will explain why we can blame California for some of our geo hazards, how coal influenced our economic development, and why it’s harder to travel east/west than north/south.
Denny Hill, Seattle, 1910
The Lecturer. David B. Williams is an author, naturalist, and tour guide whose award-winning book, Homewaters: A Human and Natural History of Puget Sound is a deep exploration of the stories of this beautiful waterway. He is also the authorof Too High and Too Steep: Reshaping Seattle’s Topography, Stories in Stone: Travels Through Urban Geology, as well as Seattle Walks: Discovering History and Nature in the City. Williams is a Curatorial Associate at the Burke Museum and writes a free weekly newsletter, the Street Smart Naturalist.
Book sale/signing. David B. Williams will bring a supply of his award-winning books for sale before and after the lecture. He accepts cash, checks and can process credit cards.
Dr. Chris Goldfinger, explores the relation of offshore turbidites to the paleoseismic record of the Cascadia subduction zone.
During this presentation, Chris described that submarine paleoseismology is a multidisciplinary science that allows us to reconstruct earthquake histories extending back thousands of years. He provided information on the use of a variety of techniques, many originally developed for petroleum exploration, to study earthquake-generated submarine deposits (turbidites). By correlating these deposits over broad areas and examining their sedimentological characteristics, we gain insight into recurrence intervals, fault rupture lengths, event clustering, long-term strain histories, paleo-slip characteristics, and interactions between faults. He compared turbidite deposits associated with recent major earthquakes (e.g., 2004 Sumatra, 2016 New Zealand) with seismological records of those events is an important part of understanding ancient earthquakes.
He explained in Cascadia, a 10,000-year onshore-offshore record, developed in large part using submarine paleoseismology, has identified periods of earthquake clustering and quiescence. The pattern – clusters of 4-5 events separated by gaps of 700-1200 years – is unlikely to be randomly generated. Cascadia is broken into at least four segments that have differing recurrence intervals, decreasing from ~ 430-500 years in the north to ~ 240 years or less in the south. However, several lines of evidence suggest that inter-event time is not a good predicter of earthquake magnitude. Long turbidite records for Cascadia and the northern San Andreas Fault also reveal that the two faults have very similar event histories about 75% of the time, suggesting these major faults can trigger one other.
Dr. Chris Goldfinger, emeritus professor at Oregon State University (OSU), is a marine geologist and geophysicist with a focus on great earthquakes and structure of plate boundary fault zones around the world. Chris has been involved in over 45 oceanographic cruises over the last 30 years, using many geophysical tools (deep submersibles, sidescan sonar, seismic reflection, etc.). He is currently working on great subduction earthquakes along the Cascadia, NE Japan, the Caribbean, and Sumatran margins, as well as the northern San Andreas Fault, where he uses the evidence for earthquakes found in deep-sea sediments.
Chris received his PhD from OSU in 1994. He is a Fellow of GSA and was the recipient of the 2016 GSA Kirk Bryan Award for Quaternary Geology. Windsurfing in the Columbia River Gorge and aerobatic flying are some of his favorite sports, as well as sailing to the south Pacific.
Chris suggested watching “Earthstorm” featured on Netflix for more on these topics.
Developing and calibrating the geologic timescale — reconstructing Earth’s past from the raw rock record — is one of humanity’s greatest, but least appreciated, intellectual achievements. But as a society, we are time illiterate, lacking a sense for the durations of the chapters in Earth’s history, the rates of change during previous intervals of climate instability, and the intrinsic timescales of ‘natural capital’ like groundwater systems. This matters because environmental wrongs, social conflicts and existential malaise are all rooted in a distorted sense of humanity’s place in the history of the natural world. Thinking like a geologist can simultaneously ground us and elevate us. Paradoxically, this Earth-bound, very physical science can yield transcendent insights.
Timefulness was longlisted for the 2019 PEN/E.O. Wilson Prize for Literary Science Writing and was a finalist for the 2018 the Phi Beta Kappa Award in Science, and the LA Times Book Prize in Science & Technology.
Marcia Bjornerud, Professor of Geosciences at Lawrence University in Wisconsin, is a structural geologist whose research focuses on the physics of earthquakes and mountain building. She combines field-based studies of bedrock geology with quantitative models of rock mechanics. She has done research in high arctic Norway (Svalbard) and Canada (Ellesmere Island), as well as mainland Norway, Italy, New Zealand, and the Lake Superior region. Bjornerud is a Fellow of the Geological Society of America and has been a Fulbright Senior Scholar at the University of Oslo, Norway and University of Otago, New Zealand. A contributing writer to The New Yorker, Wired, the Wall Street Journal and the Los Angeles Times, she is also the author of several other books for popular audiences — Reading the Rocks: The Autobiography of the Earth and Geopedia: A Brief Compendium of Geologic Curiosities.