iiinova — where your digital self keeps evolving

Brandon Shuck, PhD @seismoshuck.bsky.social · 03/06/2026

Stoked to be a co-author on this excellent paper by @eirinipoulaki.bsky.social that analyzed granites from a messy exhumed mantle section sampled during #IODP X402. Geochronology and microstructures lead to new insights on exhumation rates and strain localization along oceanic detachment faults!!

000

Brandon Shuck, PhD @seismoshuck.bsky.social · 27/09/2025

Go Crystal!! Wonderful blog post. And glad you are teaching the geophysicists what the “red and blue blobs” look like in rock form 😅😉

030

Reposted by Brandon Shuck, PhD

LSU College of Science @lsuscience.bsky.social · 24/09/2025

New study in Science Advances by @lsu.bsky.social geologist Brandon Shuck @seismoshuck.bsky.social shows the Cascadia subduction zone breaking apart in pieces—shedding light on ancient microplates, volcanic activity, and seismic hazards. More: www.lsu.edu/science/news... @lsuresearch.bsky.social

lsu.edu

Earth’s Crust Is Tearing Apart Off the Pacific Northwest — and That’s Not Necessarily Bad News

031

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

Thanks to all my collaborators for working together on this piece! I'm excited to see it published. Thanks to #NSF for the funding to conduct this research. @lsuscience.bsky.social @cascadiaeqs.bsky.social

040

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

This doesn’t change the hazard outlook for Cascadia on human timescales — the system is still capable of producing massive earthquakes and tsunamis!! However, the work will inform models of how earthquake ruptures interact with tectonic complexities, such as slab tears and transform boundaries.

151

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

All in all, it looks like the Cascadia subduction zone will be getting shorter by ~75 km, or ~8% of its total length. While the Explorer segment is not entirely detached, it is already partially decoupled and well on its way toward subduction cessation.

130

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

We think this new 4D framework can explain the pattern of past scenarios where a mid-ocean ridge approaches a trench and subduction terminates and reorganizes into a transform plate boundary. It fits incredibly well with the fossil record of subduction termination along Baja California!

131

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

Transforms can fragment the incoming oceanic plate and progressively form microplates, driving diachronous slab tearing, piecewise subduction termination, and triple junction migration.

141

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

What does this say about how subduction zones terminate? Transform faults may be a key and overlooked mechanism for past events, such as the Farallon plate breakup and subduction termination preserved along western North America.

241

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

The transform boundary formed out of necessity due to resistance to subduction of the warm and buoyant oceanic lithosphere near the RTF triple junction. A trench-perpendicular transform can efficient fragment the incoming oceanic plate and slow its subduction. The tearing pattern is shown here:

171

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

The ephemeral transform boundary, called the Nootka Fault Zone which separates the Explorer microplate from the Juan de Fuca Plate, formed as a broad shear zone in rheology homogeneous oceanic lithosphere and progressively localized over time.

151

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

The northern oceanic slab is actively tearing apart in multiple directions — a trench-parallel tear propagating from the slab edge, and trench-perpendicular tearing along a unique transform boundary, which causes breakoff of the microplate’s slab, while allowing adjacent subduction to continue.

151

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

So what did we find? We focused this study on northern Cascadia which hosts a complex Ridge-Trench-Fault triple junction. New deep-penetrating seismic reflection images and detailed earthquake catalogs reveal the subsurface architecture and evolution during subduction termination.

161

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

🚨🚨 One of the clearest pictures of a subducting slab tearing to date? I think so, but tell me what you think! Super thrilled that our manuscript on slab tearing and subduction termination just went live in Science Advances! You can read all about it for free here: www.science.org/doi/10.1126/...

22811

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

The beauty of Syros Island in Greece!

000

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

Hooray! That’s who I want to connect with

100

Brandon Shuck, PhD @seismoshuck.bsky.social · 24/09/2025

Hahah yes I should’ve made the switch earlier when the big migration happened. Alas I’m here now

120

Brandon Shuck, PhD @seismoshuck.bsky.social · 21/09/2025

Just deleted my science twitter and made a bsky... My feed was getting full of crazy stuff, and I pretty much just want to see things about rocks, earthquakes, and fluffy dogs/cats. Wassup?

4333