TY  - JOUR
A1  - Rodriguez Piceda, Constanza
A1  - Scheck-Wenderoth, Magdalena
A1  - Cacace, Mauro
A1  - Bott, Judith
A1  - Strecker, Manfred
T1  - Long-Term Lithospheric Strength and Upper-Plate Seismicity in the Southern Central Andes, 29 degrees-39 degrees S
JF  - Geochemistry, geophysics, geosystems
N2  - We examined the relationship between the mechanical strength of the lithosphere and the distribution of seismicity within the overriding continental plate of the southern Central Andes (SCA, 29 degrees-39 degrees S), where the oceanic Nazca Plate changes its subduction angle between 33 degrees S and 35 degrees S, from subhorizontal in the north (<5 degrees) to steep in the south (similar to 30 degrees). We computed the long-term lithospheric strength based on an existing 3D model describing variations in thickness, density, and temperature of the main geological units forming the lithosphere of the SCA and adjacent forearc and foreland regions. The comparison between our results and seismicity within the overriding plate (upper-plate seismicity) shows that most of the events occur within the modeled brittle domain of the lithosphere. The depth where the deformation mode switches from brittle frictional to thermally activated ductile creep provides a conservative lower bound to the seismogenic zone in the overriding plate of the study area. We also found that the majority of upper-plate earthquakes occurs within the realm of first-order contrasts in integrated strength (12.7-13.3 log Pam in the Andean orogen vs. 13.5-13.9 log Pam in the forearc and the foreland). Specific conditions characterize the mechanically strong northern foreland of the Andes, where seismicity is likely explained by the effects of slab steepening.
KW  - subduction zone
KW  - Andes
KW  - rheology
KW  - seismicity
KW  - flat-slab
Y1  - 2022
U6  - https://doi.org/10.1029/2021GC010171
SN  - 1525-2027
VL  - 23
IS  - 3
PB  - American Geophysical Union
CY  - Washington
ER  -