Upcoming Presentations

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• Three Fingered Jack: A dissected mafic composition volcano in the central Cascades

  • When
    28 Jan 2025
  •  
    5:30 PM
  • Location
    Online and in-person at Worthy Brewing

  Javaria Aziz

  Portland State University

  
  

  
  

  
  

  
  

  The central Oregon High Cascades are characterized by intra-arc extension and voluminous mafic lava flows erupted from scoria cones, shield volcanoes, and mafic composite cones. Three Fingered Jack is an eroded, large mafic composite volcano that stands out among smaller monogenetic cinder cones and shield volcanoes. It has been deeply dissected from glaciation, exposing much of its eruptive stratigraphy. Complete sequences of stacked, thin lava flows, are exposed on the southern and eastern flanks. The core of the edifice is highly stratified with layers of pyroclastic flows, scoria deposits and lava flows. The edifice core is cut by numerous dikes that are fed from intrusive plugs. In this talk, we will explore the eruptive products of Three Fingered Jack and discuss the changes in lava composition from a regional perspective.

  
  

  
  Please join us at:

  Worthy Brewing (eastside location)

  495 NE Bellevue Drive, Bend

  In the Hop Mahal Room

  
  

  5:30 pm social hour

  7:00 pm presentation

  
  

  COGS talk are free and open to the public -- all are welcome! Please join us for the social hour before the presentation.
  
  All presentations are also live-streamed through Zoom. There will be a registration link at the top of this page as we get closer to the date of this presentation.

  
  

  Show details
• How forests grow their own pot: Quantifying the role of trees as wind-wiggling, tap-dancing, and crowbar-wielding architects and builders

  • When
    25 Feb 2025
  •  
    5:30 PM
  • Location
    Online and in-person at Worthy Brewing

  Jill Marshall

  Portland State University

  
  

  
  

  
  

  
  

  
  

  
  

  
  

  
  

  
  

  
  

  In thin-soiled settings, we presume that trees play a significant role in converting rock into mobile sediment via physical weathering, with models centered on wind-driven tree throw. By combining novel force sensors at the tree-rock boundary with precipitation, solar radiation, wind, tree sway, and acoustic emission data, Jill Marshall has begun to quantify how species differences, wind, and root-water uptake contribute to tree-driven rock cracking. Her data suggests that changes in climate and forest structure may greatly influence tree-driven physical weathering and the rates at which trees grow their own soil pots.

  
  

  
  Please join us at:

  Worthy Brewing (eastside location)

  495 NE Bellevue Drive, Bend

  In the Hop Mahal Room

  
  

  5:30 pm social hour

  7:00 pm presentation

  
  

  COGS talk are free and open to the public -- all are welcome! Please join us for the social hour before the presentation.
  
  All presentations are also live-streamed through Zoom. There will be a registration link at the top of this page as we get closer to the date of this presentation.

  
  

  Show details
• Interdisciplinary volcanology: Combining geochronology and geophysics at the Three Sisters volcanic complex

  • When
    25 Mar 2025
  •  
    5:30 PM
  • Location
    Online and in-person at Worthy Brewing

  Annika Dechert

  University of Oregon

  
  

  
  

  
  

  
  

  As volcanologists, we look to the past to help us understand the future. We expect future eruption volumes, hazards, and timescales to loosely follow those of the past. This is a valuable assumption, but one that also needs to be considered. Specifically, does the magmatic system feeding the eruptions of the past match the modern-day magmatic system feeding the eruptions of the future? My research steps into this space, working to combine geochemistry, geochronology, and geophysics studies, connecting the past to the present.

  The Three Sisters volcanic complex in central Oregon is a great place to tackle an interdisciplinary project. Through geochronology, we establish younger eruption ages of two South Sister rhyolites, suggest distinct magma bodies through time, and highlight how the older eruption sequence is valuable for future hazard mitigation. Through geophysics, we identify modern anomalies in the crust below the Three Sisters and explore how they could evolve through time. By combining these two distinct but complementary datasets, we can address similarities and differences between the past and modern magmatic systems at the Three Sisters to aid in future hazard mitigation.

  
  

  Recent news coverage of Annika's work:

  U of O scientists find that South Sister was more volcanically active over shorter time frame than previously thought
  

  
  

  
  Please join us at:

  Worthy Brewing (eastside location)

  495 NE Bellevue Drive, Bend

  In the Hop Mahal Room

  
  

  5:30 pm social hour

  7:00 pm presentation

  
  

  COGS talk are free and open to the public -- all are welcome! Please join us for the social hour before the presentation.
  
  All presentations are also live-streamed through Zoom. There will be a registration link at the top of this page as we get closer to the date of this presentation.

  
  

  Show details
• Cascadia Earthquakes and Other Disasters: Are We Ready?

  • When
    22 Apr 2025
  •  
    5:30 PM
  • Location
    Online and in-person at Worthy Brewing

  Yumei Wang

  Portland State University

  
  

  
  

  
  

  
  

  
  

  Natural hazards, including Cascadia earthquakes and tsunamis, can cause extensive harm. To reduce the increasing frequency and destruction of natural disasters the nation is facing, Yumei Wang will discuss the urgent need to improve deficient lifeline systems—involving water, wastewater, electricity, natural gas, petroleum, communications, and transportation—so that we are safer and can quickly recover from natural disasters.

  
  

  
  Please join us at:

  Worthy Brewing (eastside location)

  495 NE Bellevue Drive, Bend

  In the Hop Mahal Room

  
  

  5:30 pm social hour

  7:00 pm presentation

  
  

  COGS talk are free and open to the public -- all are welcome! Please join us for the social hour before the presentation.
  
  All presentations are also live-streamed through Zoom. There will be a registration link at the top of this page as we get closer to the date of this presentation.

  
  

  Show details