Is Cascadia Overdue? We Checked 10,000 Years of Megaquakes

CHAPTERS 0:00 Is Cascadia Overdue? 0:41 The Forest That Died in One Winter 2:24 A Tsunami With No Earthquake 4:16 The Seafloor Kept Score 6:23 Line Up 10,000 Years 8:33 The Coast Is Being Loaded Right Now DATA IN THIS VIDEO Past earthquakes: the 19 seafloor sand layers (turbidites) that record quakes breaking most or all of the fault in about 10,000 years (Goldfinger and others, 2012, Table 10). Gaps are measured between neighboring layers using the OxCal combined ages, with the latest set to January 1700. The 1700 date: tree rings from dead western red cedars and Japanese written records of the tsunami (USGS Professional Paper 1707). Tsunami sites and heights in Japan: NOAA NCEI Global Historical Tsunami Database. The tsunami spreading across the Pacific is our own rough travel-time calculation from NOAA ETOPO 2022 depths; the "about ten hours" figure is from USGS. GPS: Nevada Geodetic Laboratory MIDAS velocities for 507 stations with at least 10 years of data, measured relative to the North American plate. Neah Bay (station NEAH) uses yearly averages, 1997 to 2024. The fault line offshore and the sinking plate: USGS Slab2 (the red line is the western edge of the model). Maps and 3D terrain: NOAA ETOPO 2022 and USGS 3DEP elevation. Night lights: NASA Black Marble (2016). Earthquake chances: USGS Fact Sheet 2025-3050. Photos and video: USGS, NOAA, U.S. Fish and Wildlife Service, Bureau of Land Management and Wikimedia Commons. SOURCES 1. Wirth, E., and others (2025). Earthquake Probabilities and Hazards in the U.S. Pacific Northwest. USGS Fact Sheet 2025-3050. https://pubs.usgs.gov/fs/2025/3050/fs... 2. Goldfinger, C., and others (2012). Turbidite event history: Methods and implications for Holocene paleoseismicity of the Cascadia subduction zone. USGS Professional Paper 1661-F. https://doi.org/10.3133/pp1661F 3. Atwater, B.F., Musumi-Rokkaku, S., Satake, K., Tsuji, Y., Ueda, K., and Yamaguchi, D.K. (2015). The Orphan Tsunami of 1700: Japanese Clues to a Parent Earthquake in North America, 2nd ed. USGS Professional Paper 1707. https://doi.org/10.3133/pp1707 4. NOAA NCEI. Global Historical Tsunami Database, event 361 (Cascadia, 1700). https://www.ngdc.noaa.gov/hazel/view/... 5. Blewitt, G., Kreemer, C., Hammond, W.C., and Gazeaux, J. (2016). MIDAS robust trend estimator for accurate GPS station velocities without step detection. Journal of Geophysical Research: Solid Earth 121. https://doi.org/10.1002/2015JB012552 (data: Nevada Geodetic Laboratory, https://geodesy.unr.edu) 6. Michel, S., Gualandi, A., and Avouac, J.-P. (2019). Interseismic coupling and slow slip events on the Cascadia megathrust. Pure and Applied Geophysics. https://doi.org/10.1007/s00024-018-19... 7. Pacific Northwest Seismic Network. Cascadia Subduction Zone. https://pnsn.org/outreach/earthquakes... 8. Hayes, G. (2018). Slab2: A Comprehensive Subduction Zone Geometry Model. USGS data release. https://doi.org/10.5066/F7PV6JNV NOTES The gap count depends on which ages you use. With the table's simple average ages instead of the OxCal ages, five gaps come out shorter than 326 years, not four. The shortest gaps have the least certain dates. The 3D seafloor views stretch height 2.5 times, and the coast-to-Rainier view 1.6 times. CREDITS Rialto Beach photos: Roller Coaster Philosophy, CC BY 2.0 (https://creativecommons.org/licenses/..., via Wikimedia Commons. Jodogahama Beach photos: Raita Futo, CC BY 2.0, via Wikimedia Commons. Mt. Fuji from Miho Coast: Σ64, CC BY 3.0 (https://creativecommons.org/licenses/..., via Wikimedia Commons. WATCH NEXT Mount Rainier's Real Danger Isn't an Eruption    • Mount Rainier's Real Danger Isn't an Eruption   #Cascadia #Earthquake #PacificNorthwest