2024-03-23 Brian Sherrod — New Findings on Earthquakes of Salish Lowland with Tree Analysis
We enjoyed hearing in-person USGS geologist, Dr. Brian Sherrod, on February 24, 2024 and by Zoom March 23. THE LECTURE: High-resolution dating of a multi-fault earthquake and earthquake recurrence in the Salish Lowland Dr. Brian Sherrod discusses new evidence for a multi-fault rupture. This rupture occurred along the Seattle (SFZ) and Saddle Mountain (SM) faults in the winter of 923-924 CE. He presents new evidence for a proto-historic earthquake on the Seattle fault (in the 1830s), and he talks about recurrence of large earthquakes in the Salish Lowland. He employs photographs, USGS mapping, lidar measurements, charts, and graphs to elaborate… Read more2024-03-23 Brian Sherrod — New Findings on Earthquakes of Salish Lowland with Tree Analysis
2024-04-20 Ralph Haugerud – Glacial Landscape of Puget Sound
Post-Mortem of Southern Cordilleran Ice Sheet The Lecture: Post-mortem of the southern Cordilleran Ice Sheet Death of an ice sheet can have many causes, as shown by retreat of the southern Cordilleran Ice Sheet about 15,000 years ago. East of the Cascades, the margin of active south-flowing ice retreated north as less snow fell and more melted. West of the Cascades, the Juan de Fuca lobe of the ice sheet appears to have floated away in response to rising sea level, perhaps without a proximal climatic cause. Collapse of the Juan de Fuca lobe diverted ice from the Puget lobe, which consequently stagnated… Read more2024-04-20 Ralph Haugerud – Glacial Landscape of Puget Sound