TY - JOUR

T1 - Feedback between megathrust earthquake cycle and plate convergence

AU - Martin de Blas, Juan

AU - Iaffaldano, Giampiero

AU - Tassara, Andrés

AU - Melnick, Daniel

N1 - Correction: https://doi.org/10.1038/s41598-023-47731-3 Publisher Copyright: © 2023, The Author(s).

PY - 2023

Y1 - 2023

N2 - Over million years, convergence between the Nazca and South America tectonic plates results in Andean orogeny. Over decades/centuries, it fuels the earthquake cycle of the Andean megathrust. It is well recognised that, over the geologically-long term of million years, Andean orogeny feeds back onto plate convergence rates, generating temporal changes documented throughout the Neogene. In contrast, no feedback mechanism operated over the geologically-short term by the earthquake cycle is currently contemplated. In fact, it is commonly assumed that the rates of contemporary convergence, which are accurately measured via geodesy, remain steady during the megathrust earthquake cycle. Here we investigate whether the contemporary Nazca/South America plate motion varies over year-/decade-long periods in response to megathrust stress variations associated with the earthquake cycle. We focus on the decade preceding the three largest and most recent Mw>8 earthquakes (2010 Mw=8.8 Maule, 2014 Mw=8.1 Iquique, 2015 Mw=8.3 Illapel), and find slowdowns of both Nazca and South America whole-plate motions that exceed the impact of data uncertainty or noise. We show that the torque variations required upon Nazca and South America to generate the slowdowns are consistent with that arising from the buildup of interseismic stress preceding the earthquakes.

AB - Over million years, convergence between the Nazca and South America tectonic plates results in Andean orogeny. Over decades/centuries, it fuels the earthquake cycle of the Andean megathrust. It is well recognised that, over the geologically-long term of million years, Andean orogeny feeds back onto plate convergence rates, generating temporal changes documented throughout the Neogene. In contrast, no feedback mechanism operated over the geologically-short term by the earthquake cycle is currently contemplated. In fact, it is commonly assumed that the rates of contemporary convergence, which are accurately measured via geodesy, remain steady during the megathrust earthquake cycle. Here we investigate whether the contemporary Nazca/South America plate motion varies over year-/decade-long periods in response to megathrust stress variations associated with the earthquake cycle. We focus on the decade preceding the three largest and most recent Mw>8 earthquakes (2010 Mw=8.8 Maule, 2014 Mw=8.1 Iquique, 2015 Mw=8.3 Illapel), and find slowdowns of both Nazca and South America whole-plate motions that exceed the impact of data uncertainty or noise. We show that the torque variations required upon Nazca and South America to generate the slowdowns are consistent with that arising from the buildup of interseismic stress preceding the earthquakes.

UR - https://doi.org/10.1038/s41598-023-47731-3

U2 - 10.1038/s41598-023-45753-5

DO - 10.1038/s41598-023-45753-5

M3 - Journal article

C2 - 37903833

AN - SCOPUS:85175607059

VL - 13

JO - Scientific Reports

JF - Scientific Reports

SN - 2045-2322

M1 - 18623

ER -