Speaker:
Jessica Pilarczyk
Associate Professor, Tier II Canada Research Chair in Natural Hazards, School of Environmental Science, Simon Fraser University
Talk title:
Constraining Earthquake and Tsunami Hazards Along the Cascadia Subduction Zone: Insights from Northern Cascadia
Tidal marsh in Fair Harbour containing geologic evidence for the northern limit of rupture in 1700 C.E. (Photo credit: Jessica Pilarczyk)
Tidal marsh in Fair Harbour containing geologic evidence for the northern limit of rupture in 1700 C.E. (Photo credit: Jessica Pilarczyk)Talk Abstract:
The Cascadia Subduction Zone (CSZ) is a well-recognized source of great earthquakes and tsunamis, including the 1700 C.E. event that inundated coastlines of the Pacific Northwest and generated a far-field tsunami recorded in Japan. In the absence of instrumental observations from a CSZ megathrust earthquake, the geologic record provides one of the only means to constrain the frequency, magnitude, and rupture extent of past events. Recent advances in geophysics raise the possibility of segmented or northern-focused ruptures centered offshore Vancouver Island, challenging the prevailing paradigm of exclusively margin-wide great earthquakes and suggesting scenarios that may be more frequent and, in some regions, more hazardous than previously assumed. However, earthquake reconstructions in northern Cascadia remain sparse relative to those in southern portions of the margin.
Unearthing evidence for past Cascadia earthquakes and tsunamis in Port Alberni’s tidal marsh (Photo credit: Jessica Pilarczyk)
Unearthing evidence for past Cascadia earthquakes and tsunamis in Port Alberni’s tidal marsh (Photo credit: To date, detailed reconstructions have been completed primarily in the Tofino region, leaving more than 300 km of coastline unstudied and contributing to substantial uncertainty in rupture models and regional hazard assessments. This presentation addresses the challenges inherent in reconstructing earthquake and tsunami histories in northern Cascadia, including complex coastal geomorphology and variable sediment preservation. Emerging results on the spatial distribution of coseismic subsidence are presented, illustrating how new subsidence estimates can be used to refine CSZ rupture models and reduce uncertainty in regional earthquake and tsunami hazard assessments.
Speaker Bio:
Jessica Pilarczyk in a trench containing the 1700 C.E. earthquake contact and tsunami sand. Tofino, BC (Photo credit: Anthony Giang)
Jessica Pilarczyk in a trench containing the 1700 C.E. earthquake contact and tsunami sand. Tofino, BC (Photo credit: Anthony Giang)Jessica Pilarczyk is Associate Professor and Canada Research Chair (Tier II) in Coastal Hazards in the School of Environmental Science, Simon Fraser University. She aims to understand how coastal systems have been altered by both extreme events (storms, tsunamis) and gradual environmental changes over the Holocene. Her objective is to extend the short-term instrumental record, and through this improved understanding of impacts and processes, enhance our ability to forecast how coastal systems will respond in the future. Many of the best reconstructions of coastal systems have been derived from sedimentological and paleontological proxies. She primarily uses sedimentary, geochemical, and microfossil evidence to better understand the paleo-record in a variety of coastal systems (temperate, tropical, and arid environ- ments). Her current research interests fall into, but are not limited to, three broad themes: (1) the application of microfossils in monitoring and reconstructing coastal environments, (2) the role of storms and tsunamis on coastal evolution, and (3) the assessment of the risk of future great earthquakes along subduction zone coastlines using paleoseismology. She is looking for graduate students interested in developing long-term records of coastal hazards including earthquakes, tsunamis, and storms.
This is hybrid event hosted in Geog 229 and on zoom.