Now moved to 3rd Monday evenings at 7:00 p.m. Our speaker will be Dr. Emily Cahoon, and Alyssa Smith returns with her Geology in a Nutshell News and Research.

Zoom link here.

Title: Lithium Mining in Oregon

Look for field trip description postings about 3 weeks before each trip!

Reaching Back Through Time in Death Valley

Death Valley's aridity and extensive rock record allows recognition of most of the seminal geologic events that affected western North America. This talk will survey the area's modern features that are evolving today and then work back in time to it's earliest rocks formed during the Proterozoic.

Register for the Zoom event here. (No charge for registration)

Speaker Bio:

Marli B. Miller is a tenured senior instructor II at the University of Oregon where she teaches a variety of classes including structural geology and field camp, and studies fault zones and regional geology. She is a photographer and author of several books including Roadside Geology of Oregon, 2nd ed., Roadside Geology of Washington, 2nd ed. (co-author Darrel Cowan from University of Washington), Oregon Rocks! A Guide to 60 Amazing Geological Sites, and most recently Death Valley Rocks! Amazing Geologic Sites in America's Hottest Park. She has worked in Death Valley since the mid-1980's. Copies of her books will be available for purchase at the event. Her geology photos are available for free download at geologypics.com.

Now moved to 3rd Monday evenings at 7:00 p.m. Dr. Paul Hseih will present The Geology of Oman, and Alyssa Smith returns with her Geology in a Nutshell News and Research.

Zoom link here.

Title: Geology of Oman

Description: 

For someone passionate about geology, visiting Oman is akin to an art enthusiast visiting the Louvre. Oman is well known for its Semail Ophiolite, generally considered the world's largest and best-preserved sheet of oceanic crust and upper mantle emplaced onto continent. This presentation is a photo tour of geologic sites visited during a trip organized by the UK company GeoWorld Travel and led by the company founder, James Cresswell. Among the sites visited during 8 full days of travel in northeastern Oman are: outcrop of the Moho (transition between the upper mantle and oceanic crust), mountains made of mantle rock (peridotite), sheeted dyke complex, pillow basalt, thrust sheets of marine sediments, fossilized hydrothermal vents (black and white smokers), atoll formed on top of a submarine volcano, complexly folded radiolarian chert, and the world's largest sheath fold. Contemporary ideas of how the Semail Ophiolite was emplaced onto the Arabian continental margin are briefly explored.

Paul Hsieh retired in 2018 from the U.S. Geological Survey after 41 years of service as a research hydrologist. His research at the USGS spanned over diverse topics that included groundwater flow and contaminant transport in fractured rocks, development and application of computer simulation models, interaction between groundwater and earthquakes, and volcano hydrology. One of his goals during his retirement is to visit important geological sites in the US and around the world. In the last few years, he visited the Henry Mountains of Utah, rafted down the Colorado River through the Grand Canyon, hiked to Burgess Shale fossil sites in the Canadian Rockies, and travelled to Oman to see the Semail Ophiolite.

PSU graduate student Natalie Culhane will present Understanding Mount Hood's Twin Lakes Fault, and Alyssa Smith returns with her Geology in a Nutshell News and Research.

Zoom link here.

Title: Understanding Mount Hood's Twin Lakes Fault

Description: Immediately south of Mount Hood, the Twin Lakes fault cuts off several drainage channels, forming a series of basins. This talk will summarize findings from lake sediment coring, surficial geologic mapping, geophysical surveys, and paleoseismic trenching I and my colleagues performed between two of these fault-dammed basins, Frog Lake and Lower Twin Lake, in one busy summer of 2024. Preliminary interpretations of these various data sources suggest multiple fault ruptures in recent geologic time, deeming the Twin Lakes fault an active tectonic feature that should be considered in local seismic hazard modeling.

Brief bio: Natalie Culhane is a second-year masters student at PSU working in the Active Tectonics lab under Dr. Ashley Streig. On her path to becoming a professional geologist, she has cored lake sediment from the Australian alpine, produced a USGS data release and publication on the runout lengths of earthquake-triggered landslides, and performed geohazard assessments at a local consulting firm. She currently interns part-time at DOGAMI, mapping landslides in the Sandy River corridor.

Sunday, August 10, 2025 - Noon to 3:00 PM

Our potluck picnic will be held at the Hoyt Arboretum on Sunday August 10th at noon.  There is no fee - registration is required for planning purposes and will be open from July 20th through August 9th.  GSOC members and guests are invited. 

More details will be shared as they become available.

Hazards from the Nevado del Ruiz and Mount Rainier volcanoes — Leveraging lessons learned to prevent future disasters

Mount Rainier in the central Cascade Range of the U.S. and Nevado del Ruiz near the northern end of the Andes volcanic chain in Columbia exist a hemisphere apart. Similarities in their geographies, structures, eruption processes, and hazards make them an ideal couple for comparison and instruction. Both edifices contain weak and collapse-prone rock mantled by glacially distributed rock debris. Five major rivers descend each volcano within narrow valleys that serve as conduits for lahars. 

At Mount Rainier, evidence of a lahar 500 years ago comes alive in a scant extent of oral traditions. At Nevado del Ruiz, memories remain tender and just below the surface for survivors of a 1985 lahar that caused an estimated 25,000 fatalities. During this 40-year anniversary of that catastrophic lahar, we examine an exchange program that brings together public officials and educators of each nation for purposes of education, motivation, and exchange of best practices. We demonstrate that for improvements in risk reduction, commitment to motivating populations may be as important as understanding the nature of a volcano, and that a whole community approach is necessary to maintain preparedness for high consequence/low frequency volcanic events.

Register for the Zoom event here (no charge for registration)

Speaker Bio:

Carolyn Driedger is a Hydrologist now working in Scientist Emerita status at the U. S. Geological Survey's Cascades Volcano Observatory (CVO) in Vancouver, Washington. Her science career began in 1978 with research on glaciers and glacier-related hazards in Alaska and the Cascade Range. Carolyn witnessed the May 18, 1980 catastrophic eruption of Mount St. Helens and participated in the scientific response. The experience provided an opportunity for observation and reflection about the roles of scientists in society. It set the course for participation in multiple projects across science and societal disciplines. As the USGS-CVO long-term Outreach Coordinator, Carolyn has worked in partnership with public officials, emergency planners, media, park interpreters, and educators to advance the cause of eruption preparedness.