Relation between oceanic plate structure, patterns of interplate locking and microseismicity in the 1922 Atacama seismic gap

0574082 - GFÚ 2024 RIV US eng J - Journal Article
González-Vidal, D. - Moreno, M. - Sippl, Christian - Báez, J. C. - Ortega-Culaciati, F. - Lange, D. - Tilmann, F. - Socquet, A. - Bolte, J. - Hormazábal, J. - Langlais, M. - Morales-Yáñez, C. - Melnick, D. - Benavente, R. - Münchmeyer, J. - Araya, R. - Heit, B.
Relation between oceanic plate structure, patterns of interplate locking and microseismicity in the 1922 Atacama seismic gap.
Geophysical Research Letters. Roč. 50, č. 15 (2023), č. článku e2023GL103565. ISSN 0094-8276. E-ISSN 1944-8007
EU Projects: European Commission(XE) 947856 - MILESTONE
Institutional support: RVO:67985530
Keywords : Atacama 1922 seismic gap * Chile * GNSS * interplate locking * locking degree * seismic catalog
OECD category: Volcanology
Impact factor: 5.2, year: 2022
Method of publishing: Open access
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2023GL103565

We deployed a dense geodetic and seismological network in the Atacama seismic gap in Chile. We derive a microseismicity catalog of >30,000 events, time series from 70 GNSS stations, and utilize a transdimensional Bayesian inversion to estimate interplate locking. We identify two highly locked regions of different sizes whose geometries appear to control seismicity patterns. Interface seismicity concentrates beneath the coastline, just downdip of the highest locking. A region with lower locking (27.5°S–27.7°S) coincides with higher seismicity levels, a high number of repeating earthquakes and events extending toward the trench. This area is situated where the Copiapó Ridge is subducted and has shown previous indications of both seismic and aseismic slip, including an earthquake sequence in 2020. While these findings suggest that the structure of the downgoing oceanic plate prescribes patterns of interplate locking and seismicity, we note that the Taltal Ridge further north lacks a similar signature.
Permanent Link: https://hdl.handle.net/11104/0344458