Shi (Joyce) Sim
Postdoctoral Research Associate

Shi Joyce Sim

Research Interests

Early Earth; fluid dynamics; geodynamics; melt in the mantle; multi-phase flows; numerical modeling; parallel computing; plate tectonics; planetary formation and evolution


B.S., Earth Science, University of California, San Diego (2011)
M.S., Mechanical Engineering, University of California, San Diego (2013)
Ph.D., Geophysics, Scripps Institution of Oceanography, La Jolla (2018)

Contact & Links

  • (202) 478-8483
  • Department of Terrestrial Magnetism
    Carnegie Institution of Washington
    5241 Broad Branch Road, NW
    Washington, DC 20015-1305
  • curriculum vitae


Joyce Sim is generally interested in applying fluid dynamics (across Reynolds numbers) to Earth science problems, pertaining but not limited to understanding plate boundaries like mid-ocean ridges and subduction zones, Earth's long term evolution and physical volcanology. On the high Reynolds end of the spectrum, she studied how asymmetry in a volcanic vent might affect supersonic volcanic eruptions. On the slower end of the Reynolds spectrum, Sim focuses on two-phase dynamics beneath the mid-ocean ridge system, where 90% of the world's volcanism occurs as new oceanic crust are created. Her previous work includes a general view of mid-ocean ridges, particularly the evolution of mid-ocean ridge depths through Earth's history by analyzing whole Earth mantle convection models (Sim et al 2016). Then zooming in at the ridge system, she developed the Melt in the Mantle beneath Mid-ocean ridges models or M3LT that is based on TerraFERMA (Wilson et al 2017) to use two phase flow modeling to understand the dynamics happening beneath mid-ocean ridges. One of the exciting aspect of this work is figuring out how melt focus from a wide region of melt generation to a narrow neo-volcanic zone where oceanic crust are formed. Her work recognized and analyzed a new melt focusing mechanism that is a dominant melt-focusing mechanism beneath mid-ocean ridges. Another thrilling aspect of this work is the presence of time-dependent porosity waves, that carries melt in melt rich pockets towards the ridge axis to create new oceanic crust. Sim will continue this work with the goal to understand how such systems might have worked in early Earth conditions. Collaborators include: Dave Stegman, James Day, Marc Spiegelman, and Cian Wilson.

Going full circle to where oceanic crust are "destroyed" at subduction zones, Sim currently works on applying two phase flow modeling to subduction zone to understand carbon fluxes going into Earth's mantle or released as volatiles at volcanic systems. This involves an understanding of the oceanic crust along with sediments being subducted and the dynamics of the complex subduction system, where earthquakes and volcanoes occurs. This project is part of the Deep Carbon Observatory and involves Erik Hauri, Peter van Keken, Cian Wilson, Marc Spiegelman, and Peter Kelemen.

In her free time, Sim also dabbles in seismology where she studies micro-seismic signatures of major hurricanes in the Pacific and Atlantic with Gabi Laske.