← Back to Sessions

Rock, River, Record: Reading the Geomorphic Record of Seismic Cycles Through Bayesian Inversion of River-incised Landscapes

Description: 

Earth’s topography is a complex recorder of tectonic processes due to its continuous reshaping by surface processes. Deciphering the interplay between tectonic forces and surface processes is essential for extracting quantitative information about tectonics. Successfully retrieving tectonic forcing from landscape is particularly appealing in light of recent observations showing that seismic cycle deformation leaves a distinct spatial footprint in the long-term (~100+ kyrs) morpho-structure of forearcs, suggesting that subduction landscapes could provide valuable insights into the long-term behavior of seismic cycles (Oryan et al., 2024).

Here we present a method to invert river incised landscapes for geological uplift pattern shaping the terrain. We rely on the fact that rivers incise topography at rates strongly dependent on local slope, making them well-suited to encode information about long-term vertical displacements. We leverage the normalized slope-area analysis of rivers (χ-analysis) to constrain the spatially-varying, long-term uplift function that has shaped a mountainous region using a Gauss-Newton inversion algorithm that best linearizes river elevation in χ-space. We demonstrate the resilience of our inversion method by retrieving uplift patterns from synthetic landscapes that incorporate complexities beyond those described by our stream power model. Subsequently, we apply our inversion to five natural landscapes shaped by normal faults (half-grabens) and to a 200-km-wide region of the Himalayas. We show that our inversion extracts uplift fields consistent with patterns expected from upper crustal flexure and previous estimates derived from geomorphological markers. The success of our method highlights its potential application to subduction landscapes, where it can shed light on the intricate behavior of seismic cycles over timescales far longer than those covered by current seismo-geodetic observations.

Session: The Landscape Record of Earthquakes and Faulting - I

Type: Oral

Date: 4/16/2025

Presentation Time: 08:15 AM (local time)

Presenting Author: Bar

Student Presenter: No

Invited Presentation: 

Poster Number:

Authors