TY  - JOUR
A1  - Melnick, Daniel
A1  - Hillemann, Christian
A1  - Jara Muñoz, Julius
A1  - Garrett, Ed
A1  - Cortes-Aranda, Joaquin
A1  - Molina, Diego
A1  - Tassara, Andrés
A1  - Strecker, Manfred
T1  - Hidden Holocene Slip Along the Coastal El Yolki Fault in Central Chile and Its Possible Link With Megathrust Earthquakes
JF  - Journal of geophysical research : Solid earth
N2  - Megathrust earthquakes are commonly accompanied by increased upper-plate seismicity and occasionally triggered fault slip. In Chile, crustal faults slipped during and after the 2010 Maule (M8.8) earthquake. We studied the El Yolki fault (EYOF), a transtensional structure midways the Maule rupture not triggered in 2010. We mapped a Holocene coastal plain using light detection and ranging, which did not reveal surface ruptures. However, the inner-edge and shoreline angles along the coastal plain as well as 4.3- to 4.0-ka intertidal sediments are back-tilted on the EYOF footwall block, documenting 10 m of vertical displacement. These deformed markers imply similar to 2-mm/year throw rate, and dislocation models a slip rate of 5.6 mm/year for the EYOF. In a 5-m-deep trench, the Holocene intertidal sediments onlap to five erosive steps, interpreted as staircase wave-cut landforms formed by discrete events of relative sea level drop. We tentatively associated these steps with coseismic uplift during EYOF earthquakes between 4.3 and 4.0 ka. The Maule earthquake rupture may be subdivided into three subsegments based on coseismic slip and gravity anomalies. Coulomb stress transfer models predict neutral stress changes at the EYOF during the Maule earthquake but positive changes for a synthetic slip distribution at the central subsegment. If EYOF earthquakes were triggered by megathrust events, their slip distribution was probably focused in the central subsegment. Our study highlights the millennial variability of crustal faulting and the megathrust earthquake cycle in Chile, with global implications for assessing the hazards posed by hidden but potentially seismogenic coastal faults along subduction zones.
KW  - Central Chile
KW  - megathrust earthquake
KW  - crustal fault
KW  - seismotectonic segmentation
KW  - Middle Holocene
KW  - sea level change
Y1  - 2019
U6  - https://doi.org/10.1029/2018JB017188
SN  - 2169-9313
SN  - 2169-9356
VL  - 124
IS  - 7
SP  - 7280
EP  - 7302
PB  - American Geophysical Union
CY  - Washington
ER  -