Land-Level Changes Produced by the
            <i>M</i>
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            8.8 2010 Chilean Earthquake

Farías, Marcelo; Vargas, Gabriel; Tassara, Andrés Ollero; Carretier, Sébastien; Baize, Stéphane; Melnick, Daniel; Bataille, K.

doi:10.1126/science.1192094

Cited by 139 publications

(125 citation statements)

References 3 publications

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“…Namely, when the bathymetry changes during an earthquake-up to a few metres of uplift and subsidence have been measured for recent megathrust earthquakes (Meltzner et al 2006;Farías et al 2010)-the height of the water column is adjusted, resulting in a redistribution of water. Uplift of the seafloor results in a local water mass removal and subsidence leads to a local water accumulation, see the scheme of Fig.…”

mentioning

confidence: 99%

Ocean contribution to seismic gravity changes: the sea level equation for seismic perturbations revisited

Broerse¹,

Riva²,

Vermeersen³

2014

Geophysical Journal International

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S U M M A R YDuring megathrust earthquakes, great ruptures are accompanied by large scale mass redistribution inside the solid Earth and by ocean mass redistribution due to bathymetry changes. These large scale mass displacements can be detected using the monthly gravity maps of the GRACE satellite mission. In recent years it has become increasingly common to use the long wavelength changes in the Earth's gravity field observed by GRACE to infer seismic source properties for large megathrust earthquakes. An important advantage of space gravimetry is that it is independent from the availability of land for its measurements. This is relevant for observation of megathrust earthquakes, which occur mostly offshore, such as the M w ∼ 9 2004 Sumatra-Andaman, 2010 Maule (Chile) and 2011 Tohoku-Oki (Japan) events. In Broerse et al., we examined the effect of the presence of an ocean above the rupture on long wavelength gravity changes and showed it to be of the first order.Here we revisit the implementation of an ocean layer through the sea level equation and compare the results with approximated methods that have been used in the literature. One of the simplifications usually lies in the assumption of a globally uniform ocean layer. We show that especially in the case of the 2010 Maule earthquake, due to the closeness of the South American continent, the uniform ocean assumption is not valid and causes errors up to 57 per cent for modelled peak geoid height changes (expressed at a spherical harmonic truncation degree of 40). In addition, we show that when a large amount of slip occurs close to the trench, horizontal motions of the ocean floor play a mayor role in the ocean contribution to gravity changes. Using a slip model of the 2011 Tohoku-Oki earthquake that places the majority of slip close to the surface, the peak value in geoid height change increases by 50 per cent due to horizontal ocean floor motion. Furthermore, we test the influence of the maximum spherical harmonic degree at which the sea level equation is performed for sea level changes occurring along coastlines, which shows to be important for relative sea level changes occurring along the shore. Finally, we demonstrate that ocean floor loading, self-gravitation of water and conservation of water mass are of second order importance for coseismic gravity changes.When GRACE observations are used to determine earthquake parameters such as seismic moment or source depth, the uniform ocean layer method introduces large biases, depending on the location of the rupture with respect to the continent. The same holds for interpreting shallow slip when horizontal motions are not properly accounted for in the ocean contribution. In both cases the depth at which slip occurs will be underestimated.

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mentioning

confidence: 99%

Ocean contribution to seismic gravity changes: the sea level equation for seismic perturbations revisited

Broerse¹,

Riva²,

Vermeersen³

2014

Geophysical Journal International

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“…Posteriormente, el mismo Lomnitz (1983) revisita los principales argumentos dados previamente y propone un epicentro en la costa o mar adentro, sugiriendo una fuente en la interplaca. Finalmente, basado en un reconocimiento geológico, Lomnitz (2004) especula que la fuente del terremoto de 1647 podría haber estado asociada a la falla San Ramón, una falla inversa que corre a lo largo del piedemont andino al este de Santiago (Farías et al 2010a, Armijo et al, 2010. Aunque el registro instrumental no ha detectado sismicidad cortical asociada a la falla San Ramón durante los últimos 30 años (Barrientos, 2007), recientemente se ha reportado el hallazgo de un escarpe de falla que muestra actividad entre los últimos 22.000 y 8.000 años (Vargas y Rebolledo, 2012).…”

Section: La Catástrofe De 1647 Como Un Terremoto Intraplacaunclassified

“…Considerando que los terremotos corticales, asociados a los Andes, presentan una importante tasa de atenuación de intensidad (Campos et al, 2005), y que sus expresiones superfi ciales de fallamiento se extienden solo por unas decenas de kilómetros (Charrier et al, 2005;Farías et al 2010a;Armijo et al, 2010), es difícil sostener que puedan generar daños que se extiendan latitudinalmente a escala de centenares de kilómetros, como los producidos por el evento de 1647. En esa ocasión se reportaron daños a lo largo de 400 km, entre los ríos Choapa y Maule (Montessus de Ballore, 1912).…”

Section: La Catástrofe De 1647 Como Un Terremoto Intraplacaunclassified

El terremoto de 1647 de Chile central como un evento intraplaca: ¿otra amenaza para Chile metropolitano?

Cisternas

2012

Rev. geogr. Norte Gd.

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RESUMENEl terremoto del 13 de mayo de 1647, la mayor catástrofe en la historia colonial de Chile central, es considerado como el segundo evento de la secuencia de terremotos interplaca que ha ocurrido con una sorprendente regularidad en esta parte de Chile. Sin embargo, el análisis histórico realizado sugiere que este terremoto, además de generar un enérgico y extenso sacudimiento en el valle central, no habría producido un tsunami. Ambas características podrían signifi car que se trató de un evento tipo intraplaca, originado superfi cialmente en la placa continental o profundo en la de Nazca. Los efectos reportados se asemejan más a los del terremoto de Chillán de 1939, un evento intraplaca de profundidad intermedia que aunque no produjo un tsunami generó grandes intensidades en el valle central y una enorme cantidad de víctimas. Si el terremoto de 1647 fue intraplaca, se plantea un problemático escenario de riesgo para la región más poblada del país.Palabras clave: Terremoto de 1647, terremoto intraplaca, sismología histórica, Chile central. ABSTRACTThe May 13, 1647 earthquake, the larger catastrophe in the colonial history of central Chile, is considered as the second event of the inter-plate earthquakes series that has occurred at regular intervals in this part of Chile. However, this historical analysis suggests this earthquake, besides generating a strong and widespread shaking in the central valley, did not produced a tsunami. Both features could imply it was an intra-plate event, sourced in the surface of the continental plate or deeper in the Nazca plate. The reported effects resemble those from the 1939 Chillan earthquake, a middle-depth intra-plate event that although it did not produce a tsunami it does generated large intensities in the central valley and a huge number of victims. If the 1647 earthquake was intra-plate, a problematic risk scenario is set for the most populated region of the country.

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“…Besides the consequences that a mega-earthquake has on the human activity, the released energy during the Maule earthquake and the way on which that release occurs, trigged natural phenomena that are difficult to be measured under normal conditions [Montgomery and Manga, 2003;Farías et al, 2010]. One of these events is documented and discussed here, and corresponds to the intense vertical mixing of the stratified Rapel reservoir during the Maule earthquake.…”

Section: Introductionmentioning

confidence: 99%

Strong vertical mixing of deep water of a stratified reservoir during the Maule earthquake, central Chile (M_w 8.8)

Fuente

Meruane²,

Contreras³

et al. 2010

Geophysical Research Letters

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[1] Vertical profiles of water temperature in Rapel reservoir (central Chile, 34°2′ 23″ S, 71°35′ 23″ W, 110 m.a.s.l.), recorded the hydrodynamic response of the stratified water column of the reservoir produced by the 8.8 magnitude Maule earthquake (epicentre located in 36°15′36″S, 73°14′ 20″W), showing an intense vertical mixing of deep water. The vertical mixing was characterized by changes in the potential energy of the water column and the eddy diffusivity of the mixing, and these values were used to estimate the mixing efficiency of the event. It is hypothesized that the turbulent flow that mixed the water column was mainly induced by the oscillation of the bed, although surface gravitational waves could also have contributed to the vertical mixing. So far, this is the first time that the hydrodynamic response of a reservoir during a mega-earthquake is measured and described.

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Land-Level Changes Produced by the M _w 8.8 2010 Chilean Earthquake

Cited by 139 publications

References 3 publications

Ocean contribution to seismic gravity changes: the sea level equation for seismic perturbations revisited

Ocean contribution to seismic gravity changes: the sea level equation for seismic perturbations revisited

El terremoto de 1647 de Chile central como un evento intraplaca: ¿otra amenaza para Chile metropolitano?

Strong vertical mixing of deep water of a stratified reservoir during the Maule earthquake, central Chile (M_w 8.8)

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Land-Level Changes Produced by the M w 8.8 2010 Chilean Earthquake

Cited by 139 publications

References 3 publications

Ocean contribution to seismic gravity changes: the sea level equation for seismic perturbations revisited

Ocean contribution to seismic gravity changes: the sea level equation for seismic perturbations revisited

El terremoto de 1647 de Chile central como un evento intraplaca: ¿otra amenaza para Chile metropolitano?

Strong vertical mixing of deep water of a stratified reservoir during the Maule earthquake, central Chile (Mw 8.8)

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Land-Level Changes Produced by the M _w 8.8 2010 Chilean Earthquake

Strong vertical mixing of deep water of a stratified reservoir during the Maule earthquake, central Chile (M_w 8.8)