Interaction between forearc and oceanic plate at the south‐central Chilean margin as seen in local seismic data

Haberland, Christian; Rietbrock, Andreas; Lange, Dietrich; Bataille, K.; Hofmann, S.

doi:10.1029/2006gl028189

Cited by 61 publications

(133 citation statements)

References 33 publications

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“…1). However, shallow crustal seismicity observed near the coast has also largely been observed off southern Chile (Haberland et al 2006;Lange et al 2007;Dzierma et al 2012) in regions where subducting seamounts are absent. Alternatively, it may be attributed to the presence of crustal faulting defining the contact between a paleoaccretionary prism against the continental metamorphic basement (paleo-backstop) (Contreras-Reyes et al 2013).…”

Section: Interplay Between Continental Crustal Faults and Intraplate mentioning

confidence: 99%

Structure and tectonics of the central Chilean margin (31°–33°S): implications for subduction erosion and shallow crustal seismicity

Contreras‐Reyes¹,

Ruiz²,

Becerra³

et al. 2015

Geophys. J. Int.

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S U M M A R YThe pre-and current collision of the Juan Fernández Ridge with the central Chilean margin at 31• -33• S is characterized by large-scale crustal thinning and long-term subsidence of the submarine forearc caused by subduction erosion processes. Here, we study the structure of the central Chilean margin in the ridge-trench collision zone by using wide-angle and multichannel seismic data. The transition from the upper to middle continental slope is defined by a trenchward dipping normal scarp with variable offsets of 500-2000 m height. Beneath the scarp, the 2-D velocity-depth models show a prominent lateral velocity contrast of >1 s −1 that propagates deep into the continental crust defining a major lateral seismic discontinuity. The discontinuity is interpreted as the lithological contact between the subsided/collapsed outermost forearc (composed of eroded and highly fractured volcanic rocks) and the seaward part of the uplifted Coastal Cordillera (made of less fractured metamorphic/igneous rocks). Extensional faults are abundant in the collapsed outermost forearc, however, landward of the continental slope scarp, both extensional and compressional structures are observed along the uplifted continental shelf that forms part of the Coastal Cordillera. Particularly, at the landward flank of the Valparaíso Forearc Basin (32• -33.5• S), shallow crustal seismicity has been recorded in 2008-2009 forming a dense cluster of thrust events of M w 4-5. The estimated hypocentres spatially correlate with the location of the fault scarp, and they highlight the upper part of the seismic crustal discontinuity.

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Section: Interplay Between Continental Crustal Faults and Intraplate mentioning

confidence: 99%

Structure and tectonics of the central Chilean margin (31°–33°S): implications for subduction erosion and shallow crustal seismicity

Contreras‐Reyes¹,

Ruiz²,

Becerra³

et al. 2015

Geophys. J. Int.

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“…Temporary seismological networks of the ISSA (Integrated Seismological experiment in the Southern Andes) and TIPTEQ (from The Incoming Plate to mega-Thrust EarthQuake processes) projects observed seismic events in the region during , respectively (Bohm et al, 2002Bruhn, 2003;Haberland et al, 2006). These data demonstrate that shallow earthquakes (M ≤ 5) are concentrating north and south of the Arauco Peninsula; they are related to a northeast-striking reverse fault adjacent to the Isla Santa María and to the northwest-striking Morguilla and Lanalhue faults, respectively.…”

Section: Seismicity Neotectonics and Deformation At The Arauco Penimentioning

confidence: 99%

Forearc uplift rates deduced from sediment cores of two coastal lakes in south-central Chile

et al. 2010

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The present paper introduces a new approach for deriving information about local forearc tectonics and related uplift rates based on the study of lake sediments. We investigated two coastal lakes at the south-central Chile margin, lakes Lanalhue and Lleu Lleu, located south of the Arauco Peninsula (38°S). Both lakes developed within the valleys of ancient rivers that once drained to the Pacific Ocean, being subsequently dammed by rising sills in the late Pleistocene/early Holocene. Seismic profiling and sedimentological analyses of cores from both lakes revealed similar successions consisting of marine to brackish sediments covered by lacustrine deposits. Radiocarbon dating indicates that the marine-lacustrine transition occurred at 8 ka and 8.15 ka, respectively. The correlation of this transition with global sea-level curves allowed the calculation of local uplift rates for the Holocene. Uplift rates for the lake basins amount to 0.42 ± 0.71 and 0.49 ± 0.44 mm/a, respectively, which are consistent with rates determined from a late Pleistocene marine terrace in the area. However, conspicuously higher, though likely transient, vertical movements at 8.83 ± 2.7 mm/a and 11.36 ±1.77 mm/a, respectively, were calculated for the sills that block both lakes nowadays. These barriers are interpreted to be the surface expression of a blind reverse fault associated to the Morguilla fault system, a seismically-active structure that controls uplift and folding along the adjacent Arauco Peninsula.

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“…• S (TIPTEQ Seismology), consisting of an exceptionally dense, temporary, amphibious seismic network at the south-central Chilean continental margin (Rietbrock et al 2005;Haberland et al 2006;see also Fig. 2).…”

Section: Introductionmentioning

confidence: 99%

Shear wave velocity and Poisson's ratio models across the southern Chile convergent margin at 38°15′S

2016

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Interaction between forearc and oceanic plate at the south‐central Chilean margin as seen in local seismic data

Cited by 61 publications

References 33 publications

Structure and tectonics of the central Chilean margin (31°–33°S): implications for subduction erosion and shallow crustal seismicity

Structure and tectonics of the central Chilean margin (31°–33°S): implications for subduction erosion and shallow crustal seismicity

Forearc uplift rates deduced from sediment cores of two coastal lakes in south-central Chile

Shear wave velocity and Poisson's ratio models across the southern Chile convergent margin at 38°15′S

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