Postseismic coastal uplift in southern Chile

Barrientos, Sergio; Plafker, George; Lorca, E.

doi:10.1029/92gl00210

Cited by 74 publications

(46 citation statements)

References 17 publications

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“…Deformation models often assume a purely elastic behaviour for the crust and upper mantle, and therefore the crust instantaneously responds to the motion on the rupture. When using the elastic approach, any time dependence of the deformation might be attributed to time-dependent fault slip (Kasahara, 1975;Linde and Silver, 1989;Barrientos et al, 1992). Several studies have shown good correlation between calculated positive elastic stress change and the location of aftershocks (Reasenberg and Simpson, 1992;Stein et al, 1992;King et al, 1994;Toda et al, 4 of 39 1998; Deng et al, 1999), as well as the triggering of moderate to large earthquakes Stein et al, 1994;Harris et al, 1995;Stein et al, 1997;Stein, 1999).…”

Section: Introductionmentioning

confidence: 99%

Elastic and inelastic triggering of earthquakes in the North Anatolian Fault zone

2006

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Deformation models used for explaining the triggering mechanism often assume pure elastic behaviour for the crust and upper mantle. In reality however, the mantle and possibly the lower crust behave viscoelastically, particularly at long-term scale. Consequently, the stress field of an earthquake is in general time dependent. In addition, if the elastic stress increase were enough to trigger a later earthquake, this triggered event should occur instantaneously and not many years later. Hence, it is adequate to include inelastic behaviour when analysing stress transfer and earthquake interaction.In this work, we analyse a sequence of 10 magnitude M s > 6.5 events along the North Anatolian Fault between 1939 and 1999 to study the evolution of the Coulomb stress field.We investigate the triggering of events in the series by stress transfer, taking viscoelastic relaxation into account. We evaluate the contribution of elastic stress changes, of post-seismic viscoelastic relaxation in the lower crust and mantle, and of steady tectonic loading to the total Coulomb stress field. We analyse the evolution of stress in the region under study, as well as on the rupture surfaces of the considered events and their epicentres. We study the state of the Coulomb stress field before the 1999 Izmit and Düzce earthquakes, as well as in the Marmara Sea region.In general, the Coulomb stress failure criterion offers a plausible explanation for the timing and location of the events in this area and for this sequence of events. However, we show that using a purely elastic model disregards an important part of the actual stress increase/decrease. In several cases, post-seismic relaxation effects are important and greater in magnitude than the stress changes due to steady tectonic loading. Consequently, viscoelastic relaxation should be considered in any study dealing with Coulomb stress changes. of 39According to our study, and assuming that an important part of the rupture surface must be stressed for an earthquake to occur, the most likely value for the viscosity of the lower crust or mantle in this region is 5⋅10 17 -10 18 Pa⋅s. Our results also suggest that other time-dependent processes apart from viscoelastic relaxation might have been involved in the triggering of the 1999 Düzce event. Finally, we argue that the Marmara Sea region is currently being loaded with positive Coulomb stresses at a much faster rate than would arise exclusively due to steady tectonic loading on the North Anatolian Fault.

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Section: Introductionmentioning

confidence: 99%

Elastic and inelastic triggering of earthquakes in the North Anatolian Fault zone

2006

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“…Chile is located on the tectonic convergent contact between the Nazca and South American plates, where large tsunamigenic subduction earthquakes occur, like the M w 8.8 Maule earthquake in 2010 (Madariaga et al 2010;Lay et al 2010;Vigny et al 2011), and the largest event recorded is M w 9.5 Valdivia earthquake in 1960 (Plafker and Savage 1970;Astiz and Kanamori 1986;Cifuentes 1989;Barrientos et al 1992;Vita-Finzi and Mann 1994;Lomnitz 2004). Almost all the cities in the Chilean country have experienced a megaor large-thrust earthquake in the last century.…”

Section: Introductionmentioning

confidence: 99%

Improving seismotectonics and seismic hazard assessment along the San Ramón Fault at the eastern border of Santiago city, Chile

et al. 2013

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The San Ramón Fault is an active west-vergent thrust fault system located along the eastern border of the city of Santiago, at the foot of the main Andes Cordillera. This is a kilometric crustal-scale structure recently recognized that represents a potential source for geological hazards. In this work, we provide new seismological evidences and strong ground-motion modeling from hypothetic kinematic rupture scenarios, to improve seismic hazard assessment in the Metropolitan area of Central Chile. Firstly, we focused on the study of crustal seismicity that we relate to brittle deformation associated with different seismogenic fringes in the main Andes in front of Santiago. We used a classical hypocentral location technique with an improved 1D crustal velocity model, to relocate crustal seismicity recorded between 2000 and 2011 by the National Seismological Service, University of Chile. This analysis includes waveform modeling of seismic events from local broadband stations deployed in the main Andean range, such as San José de Maipo, El Yeso, Las Melosas and Farellones. We selected events located near the stations, whose hypocenters were localized under the recording sites, with angles of incidence at the receiver\5°and S-P travel times\2 s. Our results evidence that seismic activity clustered around 10 km depth under San José de Maipo and Farellones stations. Because of their identical waveforms, such events are interpreted like repeating earthquakes or multiplets and therefore providing first evidence for seismic tectonic activity consistent with the 123Nat Hazards (2014) 71:243-274 DOI 10.1007 crustal-scale structural model proposed for the San Ramón Fault system in the area (Armijo et al. in Tectonics 29(2):TC2007, 2010). We also analyzed the ground-motion variability generated by an M w 6.9 earthquake rupture scenario by using a kinematic fractal k -2 composite source model. The main goal was to model broadband strong ground motion in the near-fault region and to analyze the variability of ground-motion parameters computed at various receivers. Several kinematic rupture scenarios were computed by changing physical source parameters. The study focused on statistical analysis of horizontal peak ground acceleration (PGAH) and ground velocity (PGVH). We compared the numerically predicted ground-motion parameters with empirical ground-motion predictive relationships from Kanno et al. (Bull Seismol Soc Am 96:879-897, 2006). In general, the synthetic PGAH and PGVH are in good agreement with the ones empirically predicted at various source distances. However, the mean PGAH at intermediate and large distances attenuates faster than the empirical mean curve. The largest mean values for both, PGAH and PGVH, were observed near the SW corner within the area of the fault plane projected to the surface, which coincides rather well with published hanging-wall effects suggesting that ground motions are amplified there.

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“…In this study, we show that volumetric viscoelastic relaxation of the asthenosphere mantle, as opposed to the post-seismic afterslip models [Barrientos and Ward, 1990;Barrientos et al, 1992], can explain the Types 1, 2, and 3 geodetic observations equally well. We first invert for a viscosity model that can best explain the post-seismic deformation data.…”

Section: Introductionmentioning

confidence: 76%

“…In this way, Barrientos and Ward [1990] proposed an afterslip model, i.e., the deeper patches of their slip model (70-150 km), to explain the post-seismic signals in Types 1 and 2 observations. For Type 3 observations, Barrientos et al [1992] inverted for another afterslip model at the depth of 50-100 km.…”

Section: Introductionmentioning

confidence: 99%

Lithospheric dynamics of Earth�s subduction zones and Martian tectonic provinces

Ding¹

2015

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This thesis investigates lithospheric dynamics of Earth's subduction zones and Martian tectonic provinces on multiple time scales ranging from short-term earthquake deformation to long-term tectonic loading. In Chapter 2, I use geodetic observations to constrain the postseismic viscoelastic deformation following the 1960 M9.5 Valdivia, Chile earthquake and quantify its stress loading on the rupture zone of the 2010 M8.8 Maule, Chile earthquake. Results of analysis reveal that the post-1960 viscoelastic process might have contributed to the triggering of the 2010 earthquake. Chapter 3 presents numerical experiments to investigate elastoplastic deformation and faulting in the overriding plates of subduction zones caused by the movement of subducted seamounts. Numerical simulations show that a group of normal faults would first appear on the seaward side of a subducted seamount, followed by a group of thrust faults on the landward side of the seamount. In Chapter 4, I use the most recent Martian gravity and topography data to constrain spatial variations in lithospheric flexural deformation for various tectonic regions on Mars. The effective lithospheric thickness is estimated to be relatively small for the plain regions in the southern highland, but relatively large for the impact basins in the northern lowland as well as for volcanic montes in the Tharis province. The regional variations in the estimated effective lithospheric thickness might reflect both spatial and temporal changes in the thermal state of Mars.

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Postseismic coastal uplift in southern Chile

Cited by 74 publications

References 17 publications

Elastic and inelastic triggering of earthquakes in the North Anatolian Fault zone

Elastic and inelastic triggering of earthquakes in the North Anatolian Fault zone

Improving seismotectonics and seismic hazard assessment along the San Ramón Fault at the eastern border of Santiago city, Chile

Lithospheric dynamics of Earth�s subduction zones and Martian tectonic provinces

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