The early evolution of a young normal fault in the Aysén Fjord, Chile
Author(s)
Coveney, Saoirse M
Bell, Rebecca E
Wils, Katleen
Lastras, Galderic
Whittaker, Alexander C
Type
Journal Article
Abstract
Seismic reflection data have been used to investigate the evolution of faults in oil and gas basins for decades and typically image deeply buried faults at low resolution, with biostratigraphic age control to date horizons at scales of 10 Myr. This study applies quantitative fault analysis techniques typically utilized in the oil and gas industry to ultra-high resolution seismic reflection data from the Aysén Fjord in Chile to investigate active faulting. By combining these fault analysis techniques with sedimentological observations of a long marine core with a new time depth relationship derived for the study area, we are able to quantitatively constrain the ages of past surface ruptures of the Río Pescado Fault at 103–104 yr timescales. This study presents a palaeoseismic record over ∼13 kyr and constrains the gradual evolution and linkage of a young fault by the hybrid fault growth model. In particular, two palaeoearthquakes, each with maximum backstripped throws of ∼2.80 and ∼1.23 m are identified, which occurred at 1,791 ± 65 cal yrs BP and ∼8,000 ± 60 cal yrs BP respectively. This research provides a proof of concept for the use of ultra-high resolution seismic reflection data combined with sediment cores as a tool to conduct quantitative well constrained palaeoseismological studies and highlights its importance in constraining the early structural evolution of faults by resolving individual segment growth and linkage over millennial timescales.
Date Issued
2025-07-01
Date Acceptance
2025-06-14
Citation
Tectonics, 2025, 44 (7)
ISSN
0278-7407
Publisher
Wiley
Journal / Book Title
Tectonics
Volume
44
Issue
7
Copyright Statement
© 2025. The Author(s). This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
License URL
Publication Status
Published
Article Number
e2025TC008835
Date Publish Online
2025-07-07