TY  - JOUR
A1  - Moreno, Marcelo Spegiorin
A1  - Melnick, Daniel
A1  - Rosenau, M.
A1  - Bolte, John
A1  - Klotz, Jan
A1  - Echtler, Helmut Peter
A1  - Báez, Juan Carlos
A1  - Bataille, Klaus
A1  - Chen, J.
A1  - Bevis, M.
A1  - Hase, H.
A1  - Oncken, Onno
T1  - Heterogeneous plate locking in the South-Central Chile subduction zone  building up the next great earthquake
JF  - Earth & planetary science letters
N2  - We use Global Positioning System (GPS) velocities and kinematic Finite Element models (FE-models) to infer the state of locking between the converging Nazca and South America plates in South-Central Chile (36 degrees S -46 degrees S) and to evaluate its spatial and temporal variability. GPS velocities provide information on earthquake-cycle deformation over the last decade in areas affected by the megathrust events of 1960 (M-w = 9.5) and 2010 (M-w = 8.8). Our data confirm that a change in surface velocity patterns of these two seismotectonic segments can be related to their different stages in the seismic cycle: Accordingly, the northern (2010) segment was in a final stage of interseismic loading whereas the southern (1960) segment is still in a postseismic stage and undergoes a prolonged viscoelastic mantle relaxation. After correcting the signals for mantle relaxation, the residual GPS velocity pattern suggests that the plate interface accumulates slip deficit in a spatially and presumably temporally variable way towards the next great event. Though some similarity exist between locking and 1960 coseismic slip, extrapolating the current, decadal scale slip deficit accumulation towards the similar to 300-yr recurrence times of giant events here does neither yield the slip distribution nor the moment magnitude of the 1960 earthquake. This suggests that either the locking pattern is evolving in time (to reconcile a slip deficit distribution similar to the 1960 earthquake) or that some asperities are not persistent over multiple events. The accumulated moment deficit since 1960 suggests that highly locked patches in the 1960 segment are already capable of producing a M similar to 8 event if triggered to fail by stress transfer from the 2010 event.
KW  - GPS
KW  - Chile
KW  - Maule
KW  - locking degree
KW  - postseismic deformation
KW  - earthquake cycle
Y1  - 2011
U6  - https://doi.org/10.1016/j.epsl.2011.03.025
SN  - 0012-821X
VL  - 305
IS  - 3-4
SP  - 413
EP  - 424
PB  - Elsevier
CY  - Amsterdam
ER  -