Along‐Dip Segmentation of the Slip Behavior and Rheology of the Copiapó Ridge Subducted in North‐Central Chile

Abstract

The segmentation and the probable extent of seismic ruptures of subduction earthquakes along-strike and downdip are still under debate and remain as open questions. Several studies have proposed that the extent of seismic ruptures might be controlled by different factors such as: the presence of fluids and sediment entering the subduction zone (

Relation Between Oceanic Plate Structure, Patterns of Interplate Locking and Microseismicity in the 1922 Atacama Seismic Gap

“…Aseismic slip continued at least until September 2020, when the Atacama seismic sequence (see below) began to shadow the SSE signal. Non‐volcanic tremor events observed in 2019 (Pastén‐Araya et al., 2022) occurred directly updip of the 2014 SSE. In September 2020, only 2.5 months before the start of our catalog and GNSS observations, the Atacama seismic sequence occurred, featuring three major earthquakes of M w > 6.…”

“…Purple contours mark the location of aseismic slip during the 2014 SSE (Klein, Duputel, et al., 2018), the red dot marks the approximate position of the 2020 SSE (Klein et al., 2023). The latitudinal range of earthquake swarms in 1973, 1979, 2006, and 2015 (Ojeda et al., 2023) is indicated by the green bracket, and the pink ellipse shows where non‐volcanic tremor was identified in 2019 (Pastén‐Araya et al., 2022). Green, yellow and orange lines mark locking degree contour lines of 0.6, 0.7, and 0.8.…”

“…Swarm‐like seismicity sequences have been observed in 2006 and 2015 close to the town of Caldera, updip of the SSE's location (Holtkamp et al., 2011; Ojeda et al., 2023), as well as ∼50–100 km further south in 2020 (Klein et al., 2021). However, this segment of the margin has until recently only been sparsely instrumented, so that a first more comprehensive analysis of its seismicity has only recently been undertaken (Pastén‐Araya et al., 2022). The Atacama region was struck by a great ( M w ∼ 8.5) earthquake in 1922 and by a similar event in 1819 (Figure 1a), thus being considered a mature seismic gap, at risk of breaking in a great subduction earthquake (e.g., Yáñez‐Cuadra et al., 2022).…”

Travel-time seismic tomography for the seismic stratigraphic interpretation of the crust around the San Rafael knickpoint at Coca River, Ecuador

“…In the case of a well-developed seismic network over the Alps, the resolution obtained is higher than the value of 0.7 (Potin 2016). For experiments in a context of active subduction, such as the Chile Trench, where adequate azimuthal coverage throughout the territory is not possible, the limit for resolution drops to 0.6 (Pastén-Araya et al 2021, Pastén-Araya et al 2022). In the case of the tomography over Ecuador (Araujo et al 2021), the resolution value is reduced to 0.5 due to using a historical database with very heterogeneous seismic networks.…”