@article{PAR00008844,
  title = {{A}n intermediate-depth tensional earthquake ({M}-{W} 5.7) and its aftershocks within the {N}azca slab, central {C}hile : a reactivated outer rise fault ?},
  author = {{M}arot, {M}. and {M}onfret, {T}ony and {P}ardo, {M}. and {R}analli, {G}. and {N}olet, {G}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A}n intermediate-depth earthquake (7 {J}anuary 2003, {M} 5.7) occurred within the subducing {N}azca plate at longitude 70.3 degrees {W}, latitude 33.8 degrees {S} and depth 113 km. {I}ts focal mechanism shows normal faulting with a slight strike-slip component. {W}e detected 50 aftershocks within {J}anuary 2003 using a temporary seismic network installed in the zone. {T}heir local magnitudes {M}-{I} range between 1.9 and 3.5, with the strongest events occurring around the mainshock. {T}heir spatial distribution, including the mainshock, defines an area of similar to (35 +/- 5) x (10 +/- 2) km(2), cutting through almost half of the slab's total thickness at an angle of similar to 60 degrees to the slab's surface. {T}his area agrees well with one of the mainshock nodal planes. {H}owever, the total seismic area, as defined by the aftershock distribution, is larger than the rupture area normally expected for an earthquake of moderate magnitude. {W}e compare the orientation of the seismic plane with the outer rise fault pattern offshore central {C}hile and find a correlation with the strike of the seafloor spreading fabric {T}he seismic sequence shows similarities with other intermediate-depth cases, notably the 13 {J}une 2005 {T}arapaca earthquake in northern {C}hile and similar cases in the {P}acific slab beneath {J}apanin all these cases, the inferred reactivated fault planes probably originate from the outer rise region, in agreement with the hypothesis that intermediate-depth seismicity is linked to inherited faults. {C}onsequently, even moderate-sized earthquakes can reactivate large areas of inherited faults within slabs at depths > 100 km. {F}urthermore, the occurrence of multiple other local events ({M}-w> 5), with similar focal mechanism and depth to the {J}anuary 2003 event, appear to indicate that the slab becomes mechanically weak similar to 100 km depth. {T}he depth extent in the slab of the reactivated pre-existing faults is likely governed by the slab's bending/unbending stress regime, i.e. the depth to the neutral plane. {D}ehydration embrittlement is a possible factor for triggering the seismic sequence.},
  keywords = {subduction ; intermediate-depth seismicity ; fault reactivation ; outer-rise faults ; dehydration embrittlement ; {CHILI}},
  booktitle = {},
  journal = {{E}arth and {P}lanetary {S}cience {L}etters},
  volume = {327},
  numero = {},
  pages = {9--16},
  ISSN = {0012-821{X}},
  year = {2012},
  DOI = {10.1016/j.epsl.2012.02.003},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00008844},
}