Subduction earthquake deformation associated with 14 November 2007, Mw 7.8 Tocopilla earthquake in Chile: Results from InSAR and aftershocks

Motagh, Mahdi; Schurr, Bernd; Anderssohn, J.; Cailleau, B.; Walter, Thomas R.; Wang, Rongjiang; Villotte, J.P.

doi:10.1016/j.tecto.2010.04.033

Cited by 49 publications

(24 citation statements)

References 41 publications

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“…Submarine profiles developed in the Mejillones Bay show that the hanging wall of the fault is not rotated horizontally for amounts larger than 8° near the surface, suggesting that the geometry for the Mejillones Fault is not listric in this case. Although the downdip continuation of the Mejillones Fault to the interplate contact has not been demonstrated, Husen et al [1999] and Motagh et al [2010] identified some seismic aftershock activity in deep structural levels of other upper plate faults close the Mejillones Fault. This suggests that some faults of the upper plate, as with the main branch of the Atacama Fault Zone and the Mejillones Fault, extend sub‐vertically and are probably rooted into the seismogenic zone.…”

Section: Discussionmentioning

confidence: 95%

Paleoseismology of the Mejillones Fault, northern Chile: Insights from cosmogenic¹⁰Be and optically stimulated luminescence determinations

Binnie

et al. 2012

Tectonics

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[1] We have undertaken the first paleoseismological study on an upper plate fault in Chile. The selected structure was the Mejillones Fault, which is marked by a conspicuous fault-scarp. Using cosmogenic 10 Be and OSL dating and detailed sedimentary logging of trenches, we have constrained the abandonment of two alluvial surfaces by fault activity at ca. 35 ka and ca.14 ka. Based on stratigraphic observation we characterized the fault evolution in four intervals over the last ca. 35 ka. During the first three intervals the fault had a steady slip rate of 0.61 AE 0.26 m/ka. The fourth interval is delineated by the last vertical fault slip and the accumulation of un-deformed hillslope deposits after ca. 3.3 ka and has a slip rate of 0.22 AE 0.06 m/ka. The younger surface abandonment was caused by two Mw $ 7 paleoearthquakes with a recurrence interval of 5.0 AE 3.5 ka. The third interval is characterized by the interaction of hillslope deposits and aseismic slip and/or centimeter scale seismic slip events. At ca. 3.5 ka, a last large (Mw $ 6.6) earthquake took place. The recurrence intervals of large (Mw > 8.5) subduction earthquakes do not appear to be the same as the recurrence intervals of the Mw $ 7 events on the upper plate Mejillones Fault.

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Section: Discussionmentioning

confidence: 95%

Paleoseismology of the Mejillones Fault, northern Chile: Insights from cosmogenic¹⁰Be and optically stimulated luminescence determinations

Binnie

et al. 2012

Tectonics

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“…Second, geometrical complexities can damage the upper plate, generate crustal faults networks and affect the mechanical behavior of the interface [ Armijo and Thiele , 1990; Melnick and Bookhagen , 2009]. This may concern at least the Arauco peninsula and the Mejillones peninsula in North Chile (23°S) [ Béjar‐Pizarro et al , 2009; Motagh et al , 2010; Comte et al , 2010]. Third, the change in obliquity of the trench may produce geometrical boundaries that affect rupture propagation.…”

Section: Discussionmentioning

confidence: 99%

Interseismic coupling, segmentation and mechanical behavior of the central Chile subduction zone

Métois¹,

Socquet²,

Vigny³

2012

J. Geophys. Res.

179

199

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[1] Global Positioning System (GPS) measurements carried out in Chile over the last two decades showed that an entire portion of the Nazca-South America subduction zone (38°S À 24°S) was locked over this period of time. The induced accumulation of elastic deformation in the upper-plate was not released until the recent Maule earthquake of 27 February 2010 (M w 8.8) that ruptured the southern part of this section. Locking or coupling between the two plates varies both with depth and along strike. Here we use our own GPS data (an updated solution of our extended network in central Chile), combined with other published data sets, to quantify the spatial variations of the coupling that prevailed before the Maule earthquake. Using a simple elastic model based on the back-slip assumption, we show that coupling variations on the subduction plane are sufficient to explain the observed surface deformation, with no need of a sliver in central Chile. We identify four segments characterized by higher coupling and separated by narrow areas of lower coupling. This segmentation is in good agreement with historical and recent seismicity in Chile. In particular the narrow zones of lower coupling seem to have stopped most large seismic ruptures, including Maule's. These zones are often associated with irregular bathymetric or coastal features (fracture zones or peninsulas). Finally, coseismic and early post-seismic slip distribution of the Maule earthquake, occurring either in previously highly or weakly coupled zones, map a complex distribution of velocity-weakening and velocity-strengthening patches on the subduction interface.

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“…The Antofagasta earthquake triggered most uplift in the southwest of the Peninsula, an area exhibiting no vertical motion in the long‐term record (Figure 10). From InSAR observations of the Tocopilla earthquake [ Motagh et al , 2010] the uplift pattern again shows a decrease of coseismic uplift toward the Peninsula. Hence from the observation of opposed surface motion on the coseismic and long‐term time scale, we conclude that uplift of Mejillones Peninsula is not the sum of a series of major coseismic deformation events.…”

Section: Discussionmentioning

confidence: 99%

Long-term persistence of subduction earthquake segment boundaries: Evidence from Mejillones Peninsula, northern Chile

et al. 2011

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The Mejillones Peninsula in northern Chile has been recognized as the surface expression of a segment boundary for large subduction zone earthquakes. The sharp contact between the rupture planes of two instrumentally recorded earthquakes, the Mw = 8.0 Antofagasta (1995) and the Mw = 7.7 Tocopilla (2007) events, is located beneath the central part of Mejillones Peninsula. We present new chronostratigraphic and structural data that allow reconstructing the evolution of the Peninsula at the surface and correlation of the latter with seismic cycle deformation on the plate interface. Uplift commenced after 3.4 Myr, as recorded in the western highland. The central graben area on the Peninsula started uplifting above sea level as an anticlinal hinge zone prior to 400 kyr ago, most probably 790 kyr ago. The resulting E‐W trending hinge exactly overlies the limit between the rupture planes of the Antofagasta and Tocopilla earthquakes. By correlating the uplift data with the slip distribution of the above earthquakes, we demonstrate that deformation and uplift is focused during the postseismic and interseismic periods of the megathrust seismic cycle with coseismic deformation opposed to the long‐term motion. Additionally, the slip deficit beneath the Peninsula accumulating between events is probably largely recovered by creep. Hence we suggest that Mejillones Peninsula owes its existence to the lateral variation of the propensity for unstable slip at the interface. Since the latter is a material property, the long‐term spatial stability of the Peninsula as a barrier to rupture propagation since at least the middle Pleistocene is a necessary consequence.

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Subduction earthquake deformation associated with 14 November 2007, Mw 7.8 Tocopilla earthquake in Chile: Results from InSAR and aftershocks

Cited by 49 publications

References 41 publications

Paleoseismology of the Mejillones Fault, northern Chile: Insights from cosmogenic¹⁰Be and optically stimulated luminescence determinations

Paleoseismology of the Mejillones Fault, northern Chile: Insights from cosmogenic¹⁰Be and optically stimulated luminescence determinations

Interseismic coupling, segmentation and mechanical behavior of the central Chile subduction zone

Long-term persistence of subduction earthquake segment boundaries: Evidence from Mejillones Peninsula, northern Chile

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Subduction earthquake deformation associated with 14 November 2007, Mw 7.8 Tocopilla earthquake in Chile: Results from InSAR and aftershocks

Cited by 49 publications

References 41 publications

Paleoseismology of the Mejillones Fault, northern Chile: Insights from cosmogenic10Be and optically stimulated luminescence determinations

Paleoseismology of the Mejillones Fault, northern Chile: Insights from cosmogenic10Be and optically stimulated luminescence determinations

Interseismic coupling, segmentation and mechanical behavior of the central Chile subduction zone

Long-term persistence of subduction earthquake segment boundaries: Evidence from Mejillones Peninsula, northern Chile

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Paleoseismology of the Mejillones Fault, northern Chile: Insights from cosmogenic¹⁰Be and optically stimulated luminescence determinations

Paleoseismology of the Mejillones Fault, northern Chile: Insights from cosmogenic¹⁰Be and optically stimulated luminescence determinations