Sedimentology seminars

Abyssal marine turbidites provide some of the longest and most spatially extensive records of subduction zone earthquake recurrence globally; however, correlation of these deposits over long distances and interpretation of synchronous emplacement requires both an understanding of the turbidite generating systems and precise dating. Here, we present an integrated suite of high-resolution bathymetry, subbottom profiles, and sediment cores from combined autonomous underwater vehicle, remotely operated vehicle, and ship-based studies at a key paleoseismic site in the southern Cascadia subduction zone. We demonstrate how widespread, earthquake-triggered landslides on the lower slope deposit discrete, proximal mass transport deposits (MTDs) that grade offshore into complex, interfingered abyssal turbidites, which correspond to records of megathrust earthquake history. We propose accretion and oversteepening of thrust folds on the lower slope both preconditions the slope to fail and provides a perpetual source of unstable material to fail during every earthquake cycle. Furthermore, we suggest the periodic and pervasive landsliding indicates coseismic deformation of the outer accretionary wedge during megathrust rupture.

This talk focuses on cascading river hazards in Taiwan generated by landslides triggered by earthquakes and tropical cyclones. Drawing on case studies from Typhoon Morakot and the 2024 Hualien earthquake, I explore how sediment pulses move through river systems, reshaping channels and sustaining hazard long after the initial event. Together, these examples show how extreme events can produce lasting and evolving impacts in steep landscapes.

Arctic landscapes are among the most vulnerable on Earth to climate change, largely due to the rapid degradation of permafrost. In steeper bedrock-dominated terrains, warming permafrost can lead to increased sediment production via mass wasting events and amplify the delivery of sediment to channels and lakes. However, there is a fundamental lack of data on current rates of sediment production and transport in Arctic watersheds, especially those still responding to post-glacial perturbations, making it impossible to predict the responses and rates of sediment transport processes under future climate change. In this talk, I will present findings from a field-based study of the Black Mountain catchment in the Aklavik Range (Canada). This site was chosen due to the presence of an alluvial fan that post-dates the retreat of the Laurentide Ice Sheet (LIS), providing a closed system where we can consider how both paraglacial and periglacial mass flow processes have influenced physical weathering and transport rates through time.