Seismicity distribution in the vicinity of the Chile Triple Junction, Aysén Region, southern Chile

Agurto‐Detzel, Hans; Rietbrock, Andreas; Bataille, K.; Miller, Matthew; Iwamori, Hikaru

doi:10.1016/j.jsames.2013.12.011

Cited by 25 publications

(30 citation statements)

References 35 publications

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“…This swarm thus clearly illustrates the potential causal relationship between volcanic and seismic activity in the study area, as is also postulated by Vargas et al (2013). This thus confirms the conclusions by Agurto-Detzel et al (2014), who argued that high-magnitude earthquakes can be related to eruptive phases of the Hudson Volcano. The MTDs at SL-D were triggered in the southernmost part of Aysén Fjord and thus hint to an earthquake source south of the fjord, toward Hudson Volcano.…”

Section: Cascading Events: Possible Link Between Seismic and Volcanicsupporting

confidence: 91%

Holocene Event Record of Aysén Fjord (Chilean Patagonia): An Interplay of Volcanic Eruptions and Crustal and Megathrust Earthquakes

et al. 2018

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In the first months of 2007, the Aysén region in southern Chile was affected by a crustal seismic swarm. Its largest earthquake (Mw 6.2) occurred in April and had its epicenter in Aysén Fjord. Seismic intensities became so high that hundreds of onshore mass movements were triggered, several of which entered into the fjord, resulting in mass transport deposits (MTDs) preserved at the fjord bottom. Here we present a Holocene record of paleo‐earthquakes in the previously unstudied Patagonian fjordland based on MTD stratigraphy. High‐resolution seismic data retrieved using two different seismic systems (sparker and TOPAS) reveal multiple older MTDs on different stratigraphic levels. Correlation of the seismic stratigraphy with sedimentological data obtained from a long Calypso core (MD07‐3117) allows conclusion on the seismic origin of these deposits. Additionally, radiocarbon dating permits constructing an age model, validated by tephrochronology, providing an age for the different MTD levels. We thus present a highly detailed paleoseismological history of the Aysén region, including at least six major Holocene earthquakes, one of which is likely related to a known megathrust earthquake. Other earthquakes are related to activity of the Liquiñe‐Ofqui Fault Zone (LOFZ), forming the main source of seismic hazard in the area. We can infer a general average recurrence time for LOFZ earthquakes of ~2,100 years in the vicinity of Aysén Fjord with clustered events during the early and late Holocene. Finally, we argue that cascading events (causal link between volcanic and seismic events) may be a frequent phenomenon along the LOFZ.

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Section: Cascading Events: Possible Link Between Seismic and Volcanicsupporting

confidence: 91%

Holocene Event Record of Aysén Fjord (Chilean Patagonia): An Interplay of Volcanic Eruptions and Crustal and Megathrust Earthquakes

et al. 2018

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“…The activity of the Cachet Fault and the Exploradores Fault Zone that we infer is further supported by the patterns of crustal microseismicity registered by a local seismic network installed between 44.6°S and 48.3°S between 2004 and 2005 [ Miller et al ., ; Agurto‐Detzel et al ., ] (Figure ). The distribution of microseismicity occurs in clusters, notably associated with the Hudson Volcano located ~80 km north of the NPI, the LOFZ, and the CTJ, and the clusters are mostly shallower than 10 km depth, where stick‐slip fault behavior and intraplate seismicity might be expected.…”

Section: Discussionmentioning

confidence: 99%

“…Agurto‐Detzel et al . [] speculated that calving events and avalanches were possible seismogenic sources for “glacial earthquakes” based on the coincidence of terminal zones of calving glaciers. We consider this explanation unlikely, mainly because (1) the interpretation was not supported by the necessary frequency analysis of the seismic waveforms, necessary to distinguish between tectonic and glacial sources [ Ekström et al ., ; Amundson et al ., ; West et al ., ]; (2) the seismic events in question occur mainly at depths between 2 and 10 km, which is not compatible with glacial triggers located at shallow depths; and (3) there are several other larger calving outlet glaciers at the NPI that do not exhibit such seismic activity.…”

Section: Discussionmentioning

confidence: 99%

“…(a) Seismicity distribution in the vicinity of the Chile Triple Junction (CTJ) with data from the study by Agurto‐Detzel et al . []. The inverted white triangles indicate locations of seismic stations.…”

Section: Discussionmentioning

confidence: 99%

“…HV: Hudson Volcano, CBM: Cerro Bayo Mine, LOFZ: Liquine‐Ofqui Fault Zone. (b) Distribution of background local seismicity at the Northern Patagonian Icefield [ Agurto‐Detzel et al ., ]. The circles represent single seismic events color‐coded by depth.…”

Section: Discussionmentioning

confidence: 99%

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Tectonic control on rock uplift, exhumation, and topography above an oceanic ridge collision: Southern Patagonian Andes (47°S), Chile

et al. 2016

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The subduction of bathymetric anomalies at convergent margins can profoundly affect subduction dynamics, magmatism, and the structural and geomorphic evolution of the overriding plate. The Northern Patagonian Icefield (NPI) is located east of the Chile Triple Junction at ~47°S, where the Chile Rise spreading center collides with South America. This region is characterized by an abrupt increase in summit elevations and relief that has been controversially debated in the context of geodynamic versus glacial erosion effects on topography. Here we present geomorphic, thermochronological, and structural data that document neotectonic activity along hitherto unrecognized faults along the flanks of the NPI. New apatite (U‐Th)/He bedrock cooling ages suggest faulting since 2–3 Ma. We infer the northward translation of an ~140 km long fore‐arc sliver—the NPI block—results from enhanced partitioning of oblique plate convergence due to the closely spaced collision of three successive segments of the Chile Rise. In this model, greater uplift occurs in the hanging wall of the Exploradores thrust at the northern leading edge of the NPI block, whereas the Cachet and Liquiñe‐Ofqui dextral faults decouple the NPI block along its eastern and western flanks, respectively. Localized extension possibly occurs at its southern trailing edge along normal faults associated with margin‐parallel extension, tectonic subsidence, and lower elevations along the Andean crest line. Our neotectonic model provides a novel explanation for the abrupt topographic variations inland of the Chile Triple Junction and emphasizes the fundamental effects of local tectonics on exhumation and topographic patterns in this glaciated landscape.

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The 2011 Hudson volcano eruption (Southern Andes, Chile): Pre-eruptive inflation and hotspots observed with InSAR and thermal imagery

et al. 2014

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Seismicity distribution in the vicinity of the Chile Triple Junction, Aysén Region, southern Chile

Cited by 25 publications

References 35 publications

Holocene Event Record of Aysén Fjord (Chilean Patagonia): An Interplay of Volcanic Eruptions and Crustal and Megathrust Earthquakes

Holocene Event Record of Aysén Fjord (Chilean Patagonia): An Interplay of Volcanic Eruptions and Crustal and Megathrust Earthquakes

Tectonic control on rock uplift, exhumation, and topography above an oceanic ridge collision: Southern Patagonian Andes (47°S), Chile

The 2011 Hudson volcano eruption (Southern Andes, Chile): Pre-eruptive inflation and hotspots observed with InSAR and thermal imagery

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