Hi everyone,

Please join us for the Geodynamics Seminar in the Seismology Seminar Room (seismology 2nd floor) this coming Monday, October 28th at 2 pm. Hanchao Jian from the Woods Hole Oceanographic Institute will be presenting for us this week. If you would like to meet with the speaker on October 28th, please email Anne Bécel ([email protected]) to set up a time.

All the best,

Conor Bacon, Josh Murray, Collin Brandl, and Terry Plank

Title: Probing fluid processes at plate boundaries using ‘full-wavelength’ seismic imaging

Abstract: 

Fluid-related processes, such as melt transport, hydrothermal circulation, and mantle hydration, are essential to understanding plate boundary dynamics. These processes are pivotal to global water, carbon, and elemental cycles, with far-reaching implications for mantle rheology, climate stability, the origin of life on early Earth, submarine resources, subduction zone dynamics, and geohazards.

Controlled-source marine seismic surveys are powerful tools for investigating these processes due to the capacity to generate high-resolution, extensive images of the oceanic lithosphere. However, traditional methods—such as ocean-bottom seismometer (OBS) traveltime tomography and multichannel seismic (MCS) reflection imaging—often leave resolution gaps at various depths, limiting the quantitative imaging of fluid-related structures.

My research focuses on advancing and applying high-resolution full waveform inversion (FWI) techniques in marine seismic studies to bridge these gaps and achieve ‘full-wavelength imaging’. In this presentation, I will highlight case studies where FWI of MCS data unveils hydrothermal pathways within the ultramafic Rainbow massif at the Mid-Atlantic Ridge. These findings, combined with Vp/Vs structures derived from local earthquake tomography, underscore the role of lithological contrasts. Additionally, I will demonstrate how FWI of OBS data helps quantify melt in the lower crust of an ultraslow-spreading ridge segment and elucidates the ocean to-continent transition at a magma-poor rifted margin offshore Nova Scotia. Finally, I will briefly discuss ongoing research projects and future research directions.

Bio: Hanchao Jian is a Research Associate at Woods Hole Oceanography Institution (WHOI). He earned his PhD in Marine Geophysics in 2017 through a joint program between Peking University and Institut de Physique du Globe de Paris (IPGP). Before joinging WHOI, he did postdoctoral research at both IPGP and Dalhousie University. His research focuses on high-resolution imaging of oceanic crustal structure at plate boundaries, with a particular interest in fluid-related processes such as hydrothermal circulation and melt dynamics.

Zoom link:

https://columbiauniversity.zoom.us/j/92780275650?pwd=BgfOzfYBkYE2iTUEKMkE2wJLoDI7Ul.1

Meeting ID: 927 8027 5650

Passcode: 582874

For a complete view of the planned seminars this semester, please visit the calendar on the Geodynamics Seminar webpage.