TY  - JOUR
A1  - Melnick, Daniel
A1  - Moreno, Marcos
A1  - Motagh, Mahdi
A1  - Cisternas, Marco
A1  - Wesson, Robert L.
T1  - Splay fault slip during the M-w 8.8 2010 Maule Chile earthquake
T2  - Geology
N2  - Splay faults are thrusts that emerge from the plate boundaries of subduction zones. Such structures have been mapped at several convergent margins and their activity commonly ascribed to large megathrust earthquakes. However, the behavior of splay faults during the earthquake cycle is poorly constrained because typically these structures are located offshore and are difficult to access. Here we use geologic mapping combined with space and land geodesy, as well as offshore sonar data, to document surface-fault ruptures and coastal uplift at Isla Santa Maria in south-central Chile (37 degrees S) caused by the 27 February 2010 Maule earthquake (M-w 8.8). During the earthquake, the island was tilted parallel to the margin, and normal faults ruptured the surface and adjacent ocean bottom. We associate tilt and crestal normal faulting with growth of an anticline above a blind reverse fault rooted in the Nazca-South America plate boundary, which slipped during the Maule earthquake. The splay fault system has formed in an area of reduced coseismic plate-boundary slip, suggesting that anelastic deformation in the upper plate may have restrained the 2010 megathrust rupture. Surface fault breaks were accompanied by prominent discharge of fluids. Our field observations support the notion that splay faulting may frequently complement and influence the rupture of subduction-zone earthquakes.
Y1  - 2012
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/36095
SN  - 0091-7613
VL  - 40
IS  - 3
SP  - 251
EP  - 254
PB  - American Institute of Physics
CY  - Boulder
ER  -