FISH Lecture - Xiaotao Yang (Harvard)

Xiaotao Yang (Harvard)
Friday, February 21, 2020 - 12:00pm to 1:00pm

Dr. Xiaotao Yang, a Research Associate at Harvard, presents "Subduction segmentation along the Aleutian-Alaska margin and implications on the distribution of volcanic activity " at the MIT Earth Resources Labroatory.

"The along-strike variation of subducting slabs and volcanic activities has been observed globally. It is, however, unclear what controls the spatial distribution of volcanoes and the associated magma generation and migration. The Aleutian-Alaska margin, with non-uniform volcanism, is an ideal place to investigate this issue. Using full-wave ambient noise tomography, we present a high-resolution 3-D shear-wave velocity model of the Aleutian-Alaska margin. The model reveals distinct high-velocity features of the northwesterly dipping Pacific slab, the thicker, flatter, and more heterogeneous Yakutat slab, and the northeasterly dipping Wrangell slab. The linear Aleutian arc volcanoes reflect typical arc magmatism, with low-velocity partial melts within the uppermost mantle. The presence of a large low-velocity crustal magma reservoir beneath the Wrangell volcanic field accounts for the relatively large eruption volume and the clustering of volcanoes. The Denali volcanic gap is located above an average-velocity crust but an extremely fast mantle wedge, suggesting the lack of melt. Our findings explain the diverse volcanic activity along the Aleutian-Alaska margin, demonstrating the importance of mantle wedge dynamics and characteristics of the overriding crust in controlling arc magmatism."

"I am a seismologist, using seismological methods to solve geological/tectonic problems and to understand natural hazards. I am interested in a variety of research topics, including intraplate seismicity, structure and evolution of intracratonic basins and uplifts, dynamics of subduction systems, and improvements in seismic data processing methods. As a long-term interest, I aim to integrate results from multidisciplinary research fields, including geology, geophysics, geochemistry, and geodynamics in addressing tectonic questions. Since June 2019, I have been working in the vibrant Earthquake Seismology lab at Harvard University, under the supervision of Dr. Marine Denolle. I am conducting research on several exciting topics, mostly focusing on a better characterization of seismic wavefields and earthquake hazards for megathrust earthquakes at subduction zones, as well as earthquakes occurring along strike-slip faults. Prior to joining Harvard, I worked in the Seismology Lab at the Department of Geosciences, the University of Massachusetts Amherst from November 2016 to May 2019, as a postdoctoral researcher. At UMass, I had been focused on high-resolution tomography of crust and upper mantle structure beneath the northeastern U.S and Alaska. For my doctoral program, as a member of the collaborative OIINK (Ozark, Illinois, Indiana, and Kentucky) experiment, I worked with many researchers in geology, geophysics, and tectonics from multiple institutions. My Ph.D. projects involved in utilizing the high-quality seismic records from the OIINK network combined with the EarthScope USArray Transportable Array data and data from other regional networks."

FISH is the MIT Earth Resource Laboratory's Friday Informal Seminar Hour. Held most Fridays during the academic year in 54-209, the series features talks in our lab's areas of interest: geophysics, seismology, rock physics, imaging, inversion/inference, and machine learning.