Future Meetings

February 2, 2026 SCGS Meeting and Lecture

Tuesday, February 2 at 6:00 PM

South Coast Geological Society invites you to attend our February meeting. Our lecturer, Nicholas Barth, spearheaded the creation of a new lidar-based San Gabriel Mountains bedrock landslide inventory that will be hosted by CGS (<10L landslides). His talk will feature an in depth discussion of the efforts to date some of the larger landslides to better understand their hazard and impact. Please come join us at Barth’s lecture titled: Legacy and Recurrence of Bedrock Landslides in the San Gabriel Mountains, CA

Speaker: Nicholas Barth

Position: Associate Professor of Geology at University of California, Riverside

Topic: Legacy and Recurrence of Bedrock Landslides in the San Gabriel Mountains, CA

When: Tuesday, February 2, 2026 @ Dave & Busters 20 City Blvd W, Orange, CA 92868

Abstract:

More than 90% of the 2400 km2 catchment area of the actively uplifting San Gabriel Mountains (SGM) drains southward towards Los Angeles, the second largest metropolitan area in the United States, through an extensive reservoir and flood control system. In terms of downstream effects, the SGM is arguably one of the most important mountain ranges in the United States. The prevailing view is that short-return fire-flood-debris flow cycles dominate denudation of the SGM, however, emerging research suggests the role of bedrock landslides is likely significantly underappreciated. This talk will highlight (1) geochronology results that demonstrate that some of the largest landslides in the SGM formerly thought to be Early Quaternary in age (1-2.5 Ma) occurred during the Late Holocene, (2) a bedrock landslide inventory of the SGM with over 11,000 landslide deposits that significantly increases their known abundance, and (3) case studies of major landscape effects including 150m vertical aggradation pulses and drainage reorganizations driven by landslides. This new perspective has important implications for the Los Angeles region, particularly if many of these landslides are coseismically triggered. To our knowledge the SGM landslide inventory (LSI) is the only systematic, range-scale, lidar-resolution inventory of its kind in the world to date; the talk will also cover some of the novel techniques employed to produce this LSI, example spatial analyses it enables, and ongoing efforts to have the database incorporated into the California Geological Survey’s statewide LSI.

Speaker Information:

Nicolas Barth is an Associate Professor of Geology at the University of California, Riverside. He received a BSc & MSc in Geology at UC Santa Barbara and a PhD at the University of Otago in New Zealand. Among diverse research interests, his main aim is to improve our understanding of active faults, bedrock landslides, and the evolution of landscapes.

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Thank you to our individual and corporate sponsors whose generous donations help make these events sustainable! If you or your company would like to become a 2026 corporate sponsor, please contact scgs.mgmt@gmail.com.

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Meeting Information:

Location:

Dave and Busters

20 City Blvd West

Orange, CA

Meeting Cost:

Member: $50

Non-Member: $60

Students: $20

Membership Dues:

As a reminder, annual membership dues expire at the end of each calendar year. 2026 Membership dues can be paid via Eventbrite as a registration add-on: $40

Agenda:

6:00 PM – Check-in and social hour

6:30 PM – Dinner served

7:00 PM – Presentation begins after brief announcements

Registration:

Please register by Friday, January 30. Walk-ins are accepted, but early registration helps ensure enough food is prepared.