Impact of the Iquique Ridge on structure and deformation of the north Chilean subduction zone

Ma, Bo; Geersen, Jacob; Klaeschen, Dirk; Contreras‐Reyes, Eduardo; Riedel, Michael; Xia, Yueyang; Tréhu, Anne M.; Lange, Dietrich; Kopp, Heidrun

doi:10.1016/j.jsames.2023.104262

Cited by 6 publications

(2 citation statements)

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“…Oceanic basement features vary in height, composition, and surface morphology and exhibit a wide variety of forms, comprising conical shapes (peaked or flat‐top), multiple branches, or parallel ridges (Figures 1b and 1c). Seamounts, which represent one of the most common and most widespread topographic features on oceanic plates, have been documented within numerous subduction zone systems, including Tonga‐Kermadec (Timm et al., 2013), Nankai (Bangs et al., 2006), Japan and Kuril (Lallemand et al., 1989), Cascadia (Tréhu et al., 2012), Hikurangi (Bell et al., 2014), northern Chile (Ma et al., 2023), and Central America (Ranero & Von Huene, 2000). Upper plate deformation associated with seamount subduction is manifested by re‐entrants or scarps at the margin toe (Ranero & Von Huene, 2000), gravitational submarine landslides (Brune et al., 2010), strike‐slip faulting (Davidson et al., 2020), regional uplift (Laursen et al., 2002) or the landward shift of the deformation front (Kopp et al., 2006).…”

Section: Introductionmentioning

confidence: 99%

Seamount and Ridge Subduction at the Java Margin, Indonesia: Effects on Structural Geology and Seismogenesis

Xia,

Kopp,

Klaeschen

et al. 2023

JGR Solid Earth

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The Java ‐ Lesser Sunda margin, which features multi‐scale subducting oceanic basement relief, is classified as neutral (Lombok and Sumbawa) to erosional (Central Java to Bali) in comparison to its accretionary counterpart offshore Sumatra. However, a comprehensive analysis of how plate boundary and upper plate structure across the neutral to erosional transition are modulated by the subduction of oceanic basement relief is lacking to date. To shed light on the tectonic parameters that push the margin into the neutral or erosional domain, we combine multi‐channel reflection seismic images derived through a grid‐based P‐wave velocity inversion, and multibeam bathymetric maps. The data document how different scales of subducting topography modify seafloor morphology, upper plate structure, and décollement position. Large‐scale subducting features cause a landward shift of the deformation front, shortening of the accretionary wedge, and seafloor steepening at the relief's trailing edge. Small‐scale subducting ridges primarily impact the frontal prism resulting in over‐steepening at the trench and localized slope failure. Ahead of subducting relief, deformation of the accretionary wedge encompasses enhanced compression and a reduction in seafloor slope but appears independent of the size of the relief. Ridge and seamount subduction induce frontal erosion and basal erosion offshore Lombok and Bali, respectively. Our P‐wave velocity models indicate that the rigidity of the upper plate's base along the eastern Sunda margin is significantly lower than the worldwide trend. We conclude that this favors the genesis of tsunami earthquakes that have occurred on the Java margin.

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Section: Introductionmentioning

confidence: 99%

Seamount and Ridge Subduction at the Java Margin, Indonesia: Effects on Structural Geology and Seismogenesis

Xia,

Kopp,

Klaeschen

et al. 2023

JGR Solid Earth

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“…By correlating gravity anomalies with bathymetry, studies have demonstrated the frictional control of individual geologic features on the spatial variation of seismogenic behaviour at subduction zones (Bürgmann et al, 2005;Song & Simons, 2003). Commonly observed features causing perturbations in the stress field at the plate interface include aseismic ridges (e.g., Ma et al, 2023), fracture zones (e.g., Kasahara et al, 1997), and seamounts (e.g., Bonnet et al, 2019). The relationship between roughness and seismicity has been well demonstrated at the southern America subduction zone where the spatial pattern of many large subduction earthquakes mimics the distribution of topographic highs which serve to segment the plate boundary (Bilek, 2010;Metois et al, 2016).…”

Section: Subducting Sediment Thickness and Roughnessmentioning

confidence: 99%

Integrating onshore and offshore paleoseismic evidence to reveal past large earthquakes on the weakly coupled central Hikurangi margin, New Zealand

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Determining the location and recurrence of seismic slip at subduction zones is essential for constraining the hazard posed by great earthquakes. Although modern geodetic observations have revealed interseismically locked regions of the plate interface, it is unclear to what degree this reflects the potential for future rupture given the broad spectrum of possible slip behaviour and short instrumental record. Developing paleoearthquake records over multiple seismic cycles is therefore a powerful method of understanding spatiotemporal patterns in seismic slip behaviour at subduction margins. Conditionally stable parts of the plate interface adjacent to locked patches are identified as particularly important places to constrain long-term behaviour due to their potential to host multiple styles of interface slip.This thesis explores temporal variation in slip behaviour at subduction zones by investigating the paleoseismic record on the weakly coupled central Hikurangi margin in New Zealand. Previously, interpretation of paleoearthquake evidence in this region has been hindered by poorly constrained chronology, sparse distribution of study sites and incomplete consideration of source faults. Generating new paleoearthquake records was therefore necessary to constrain the timing and extent of large earthquakes, and to decipher whether they could represent rupture of the plate interface. Where precisely-dated tephra isochrons are available, they can provide a useful tool for accurate chronostratigraphic correlation between paleoseismic sites and improved temporal constraints within age-depth models of Holocene paleoearthquake chronologies. The age of the Waimihia tephra isochron was refined to 3574–3478 cal yr BP using integrated age modelling of 42 radiocarbon dates from proximal, distal onshore, and distal offshore locations. Using the refined isochron age alongside 68 radiocarbon dates, a new 5000-year record of four precisely-dated paleoearthquakes was generated at the Pakuratahi Valley near Napier, as a key locality for examining onshore coseismic deformation on the central Hikurangi margin. The evidence of both coseismic subsidence and uplift could have been caused by earthquakes on upper plate faults and/or the plate interface. To better distinguish between these sources and expand the paleoseismic record in space and time, a 7000- year record of seismoturbidites was developed from a suite of submarine sediment cores spanning the central margin. Integrating the onshore and offshore datasets permitted better characterization of evidence for widespread synchronous deformation across the central margin. The new interpretation of paleoseismic correlations suggests rupture of upper plate faults could generate some of the observed patterns of surface deformation, but that seismic slip on the subduction interface is likely for most earthquakes.Temporal agreement between the central Hikurangi paleoearthquakes and subduction earthquakes recorded on the southern, locked section of the margin provides strong evidence that multi-section ruptures, spanning a distance of >300 km, may have occurred. Examining the pattern of coseismic deformation on the central margin alongside current understanding of geophysical properties highlights the weakly coupled region of the interface between slow slip zones as an important location for propagating rupture along-strike from the locked patch. Conditional stability of this region is implied as a mechanism for supporting coseismic slip on the currently creeping part of the central Hikurangi margin. These observations add to the growing literature that suggests weakly coupled parts of the plate interface adjacent to locked patches can host multiple modes of interface slip and should therefore be considered a region of significant seismic hazard, due to their ability to support great (>Mw 8) multi-section subduction earthquakes.

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Offshore geometry of the South America subduction zone plate boundary

Contreras-Reyes,

Carvajal,

González

2025

Earth and Planetary Science Letters

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Impact of the Iquique Ridge on structure and deformation of the north Chilean subduction zone

Cited by 6 publications

References 61 publications

Seamount and Ridge Subduction at the Java Margin, Indonesia: Effects on Structural Geology and Seismogenesis

Seamount and Ridge Subduction at the Java Margin, Indonesia: Effects on Structural Geology and Seismogenesis

Integrating onshore and offshore paleoseismic evidence to reveal past large earthquakes on the weakly coupled central Hikurangi margin, New Zealand

Offshore geometry of the South America subduction zone plate boundary

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