I'm a seismologist, which means I spend my days looking at wiggles on a screen.
Typically these wiggles are recorded using very expensive slinkies (seismometers) buried in
the ground, which shake and bounce due to earthquakes, the oceans, or people doing things.
My particular interest is in the field of seismic imaging (specifically, adjoint tomography),
which means I use seismic waves and supercomputers to probe and understand the structure of the
Earth (think MRI or CT scans).
In adjoint tomography, we generate fake wiggles using computer simulations and 3D Earth models.
By systematically changing the model, we can line up the fake wiggles with the real wiggles.
Ultimately, this updated model can give us a better idea about the ground beneath our
feet. Neat!
My research in a nutshell: [left] a computer simulation of seismic waves radiating away
from an earthquake (black star) to be recorded by a seismometer (white triangle);
[right] vertical shaking comparing the actual recording of this earthquake (black) and the
simulated shaking (red). Note that time is sped up dramatically.
In October 2022, we held a virtual SPECFEM Users Workshop to teach new users how to use the spectral element solver, SPECFEM. Leveraging Docker containers, Jupyter notebooks and Zoom, we were able to host up to 180 participants over three days, where they learned how to run forward simulations, generate sensitivity kernels, and perform seismic inversions. Recordings and workshop material is free and available for use, check it out!
Using our new model of the Earth's crust below the North Island of New Zealand, myself and co-authors suggested that we have imaged two previously-unrecognized seamounts (underwater mountains) subducted below the continent. Their presence may affect how we think about seismic activity within this region. This work was chosen for an Editor's highlight in Eos!
My doctoral research (now published as a pair of companion papers: 1, 2) involved seismic imaging of the Hikurangi subduction zone and tectonic interpretations of newly resolved structures in the crust below the North Island of New Zealand. We employed an imaging method known as adjoint tomography, which seeks to minimize differences between observed and simulated seismic waveforms.
I am developing open-source Python packages that facilitate the automation of adjoint tomography workflows (SeisFlows), and seismic data handling and misfit quantification within these workflows (Pyatoa).
One of the main products of my PhD was the New Zealand Adjoint TOMography model (NZ ATOM). NZ_ATOM_north is an adjoint tomography-derived velocity model for the North Island of New Zealand, and the adjacent Hikurangi subduction zone.
The Broadband EAst COast Network (BEACON) was a temporary deployment of 20 broadband seismic instruments in the central Hawke's Bay and Tararua regions. The network was deployed to supplement receiver coverage over the Hikurangi subduction interface.
My master's work involved analysis of amplitudes from rotational ground motion sensors. Using a large catalog of global earthquakes, we empirically derived a rotational magnitude scale to understand the charactersitics of amplitude decay for rotation signals. I was also involved in development of a rotational seismology event database.
National Science Foundation Postdoctoral Fellow (2021 – 2023)
Active Tectonics and Crustal Structure of Northern Alaska
University of Alaska Fairbanks, Fairbanks, Alaska
Scientific Mentor: Carl Tape
Postdoctoral Researcher (May – September, 2021)
GNS Science, Lower Hutt, New Zealand
PhD, Geophysics (2018 – 2021)
Adjoint tomography of the Hikurangi subduction zone and the North Island of New Zealand
Victoria University of Wellington, Wellington, New Zealand
Advisors: Yoshihiro Kaneko, John Townend
(2021 Doctoral Dean's List recipient)
MSc, Geophysics (2015 – 2017)
Analysis of rotational motion amplitudes on local and global scales
Ludwig-Maximilians-Universität München & Technische Universität München, Munich, Germany
Advisors: Heiner Igel, Celine Hadziiannou, Stefanie Donner, Joachim Wassermann
BSc, Physics // Minor in German Studies (2011 – 2015)
Determining Love wave phase velocity through analysis of rotational ground motion
University of California Santa Barbara, Santa Barbara, California
Advisor: Toshiro Tanimoto
Strong upper-plate heterogeneity at the Hikurangi subduction margin (North Island,
New Zealand) imaged by adjoint tomography
Bryant Chow, Yoshihiro Kaneko, Carl Tape, Ryan Modrak, Nick Mortimer, Stephen Bannister,
John Townend
Journal of Geophysical Research: Solid Earth 127.1 (2022): e2021JB022865.
Evidence for deeply-subducted
lower-plate seamounts at the Hikurangi subduction margin: implications for seismic and
aseismic behavior
Bryant Chow, Yoshihiro Kaneko, John Townend
Journal of Geophysical Research: Solid Earth 127.1 (2022): e2021JB022866.
(EOS Editor's Highlight: Adjoint tomography illuminates Hikurangi margin complexity)
An automated workflow for adjoint
tomography — Waveform misfits and synthetic inversions for the North Island,
New Zealand
Bryant Chow, Yoshihiro Kaneko, Carl Tape, Ryan Modrak, John Townend
Geophysical Journal International 223.3 (2020): 1461-1480.
Love wave amplitude decay from
rotational ground motions
Bryant Chow, Joachim Wassermann, Berhard S A Schuberth, Celine Hadziioannou,
Stefanie Donner, Heiner Igel
Geophysical Journal International 218.2 (2019): 1336-1347.
Fieldwork at Giotto's Bell Tower on the Piazza del Duomo, where we installed broadband and rotational seismometers at various floors to measure the normal modes of this freestanding tower (Florence, Italy; 2016).
I received formal training to operate 4WD vehicles and side-by-sides (pictured) to take on BEACON fieldwork (mentioned above). Typically this involved zippin' around muddy farm paddocks and lugging marine batteries in and out of a ute (Hawke's Bay, New Zealand; 2018).
Fieldwork has gotten me to some amazing places, like this snow-covered mountain top in the southern Alps (New Zealand), where our seismic station was buried so deep we had to break out the GPS to figure out where to dig (Southern Alps, New Zealand; 2018).
I have experience installing, servicing and removing a variety of seismic site installations, from temporary (battery-only), to semi-permanent (solar panel sites; pictured) to permanent (hooked up to city mains) stations (Southern Alps, New Zealand; 2018).
During my PhD, I had the privilege to join in on "South Island fieldwork" (twice!) maintaining seismic stations along New Zealand's Alpine Fault, either from the tailgate of a ute, or (shown here) ferried in by some of New Zealand's finest heli pilots (Southern Alps, New Zealand; 2018).
I started climbing in 2012, on sandstone boulders in Santa Barbara. I learned to lead and fall at Malibu Creek and New Jack City, and have been lucky enough to climb in Bishop, Joshua Tree, Tahoe, Yosemite, the Bavarian pre-alps, seaside crags around New Zealand, and on granite outcrops in interior Alaska. Rock climbing was a big inspiration for studying Earth science. Pictured: topping out Crystal Crag (Mammoth Lakes, California; 2015).
I got my first bike (Suzuki DRZ400S) in 2013. I generally consider that a solid life decision. Since then I've owned a Honda CBR600F4i and a Suzuki DR650. I'm equally happy carving canyon roads or sliding around on dirt and gravel (see video below). Pictured: our group of hooligans on Coast Rd. (Wainuiomata, New Zealand; 2019).
Occasionally I can be persuaded to dip my toes in the water, e.g., pictured here preparing to embark on a five day pre-Christmas canoe ride down the Whanganui river, North Island New Zealand (Whanganui, New Zealand; 2020).
I moved to Alaska in September, 2021. It snowed that week and then I didn't see the ground until April. Naturally I picked up winter sports. Here you see me prepped for an 11 mile trip to Tolovana Hot Springs, where I quickly realized I was a below-average skiier, that we had packed too much weight into our pulk (gear sled), and that I really enjoy an Alaskan winter (Elliot Highway, Alaska; 2022).
My first time riding over Devil's Gate, Red Rocks, on Wellington's South Coast, just down the road from my flat in Wellington. I had only started riding my motorbike offroad a few weeks earlier, so tackling this steep rock face had my heart pounding (Wellington, New Zealand; 2018).