Welcome to Dr. Yoshi's world!

Welcome to the world of Dr. Yoshi! My name is Johan Gilchrist (Yoshi is my nickname) and I'm a National Science Foundation (EAR) Postdoctoral Fellow at the University of Oregon. I study the multiphase fluid dynamics of explosive volcanic eruptions, such as the 1980 eruption of Mt. St. Helens and the 2022 eruption of Hunga Tonga-Hunga Ha'apai using a combination of field-, laboratory- and computer-based methods. The ultimate goal of my research is to improve our understanding of the evolution of hazards during an eruption and the effects on Earth's surface, atmosphere and oceans for past and future eruptions. I also study glaciers and landslides in mountainous environments, particularly their response to climate change, and have extensive field experience working in these terrains. 

Recent Research

Our research featured in Nature Geoscience explores how the terraced slopes of submarine caldera volcanoes, such as Santorini, Greece, can be used to estimate elusive eruption source conditions. We show that fountain physics causes caldera-forming eruption columns to collapse periodically as doughnut shaped sedimentation waves that impact the sea surface to generate tsunamis, surfing hot rock avalanches, and submarine pyroclastic density currents that build terraced deposits on the seafloor. Our results may help explain why large caldera-forming eruptions, like the Jan 15, 2022 eruption of Hunga Tonga Hunga-Ha'apai, can have surprisingly little effects on climate. Free to download for a limited time here:

Submarine terraced deposits linked to periodic collapse of caldera-forming eruption columns. Gilchrist et al. 2023, Nature Geoscience

Listen to my overview of our work on CBC Radio's Quirks and Quarks:


Hunga Tonga Hunga Ha'apai Eruption 

Check out last year's UBC EOAS article on my ongoing study with Colin Rowell and Mark Jellinek on the Hunga Tonga-Hunga Ha'apai eruption that occurred on January 14th: 


NASA GOES-West Satellite view of the January 15, 2022 climactic eruption of Hunga Tonga Hunga Ha'apai volcano. Photo credit: NOAA.

Contact Information

Dr. Johan Gilchrist (he/him/his)

NSF EAR Postdoctoral Fellow

Dept. Earth Sciences

University of Oregon

Volcanology 206

1255 E 13th Avenue

Eugene, OR 97401

jgilchr2 @ uoregon dot edu

Curriculum Vitae