TY - JOUR A1 - Moreno, Marcelo Spegiorin A1 - Melnick, Daniel A1 - Rosenau, M. A1 - Báez, Juan Carlos A1 - Klotz, Jan A1 - Oncken, Onno A1 - Tassara, Andres A1 - Chen, J. A1 - Bataille, Klaus A1 - Bevis, M. A1 - Socquet, Anne A1 - Bolte, John A1 - Vigny, C. A1 - Brooks, B. A1 - Ryder, I. A1 - Grund, Volker A1 - Smalley, B. A1 - Carrizo, Daniel A1 - Bartsch, M. A1 - Hase, H. T1 - Toward understanding tectonic control on the M-w 8.8 2010 Maule Chile earthquake JF - Earth & planetary science letters N2 - The Maule earthquake of 27th February 2010 (M-w = 8.8) affected similar to 500 km of the Nazca-South America plate boundary in south-central Chile producing spectacular crustal deformation. Here, we present a detailed estimate of static coseismic surface offsets as measured by survey and continuous GPS, both in near- and far-field regions. Earthquake slip along the megathrust has been inferred from a Joint inversion of our new data together with published GPS, InSAR, and land-level changes data using Green's functions generated by a spherical finite-element model with realistic subduction zone geometry. The combination of the data sets provided a good resolution, indicating that most of the slip was well resolved. Coseismic slip was concentrated north of the epicenter with up to 16 m of slip, whereas to the south it reached over 10 m within two minor patches. A comparison of coseismic slip with the slip deficit accumulated since the last great earthquake in 1835 suggests that the 2010 event closed a mature seismic gap. Slip deficit distribution shows an apparent local overshoot that highlight cycle-to-cycle variability, which has to be taken into account when anticipating future events from interseismic observations. Rupture propagation was obviously not affected by bathymetric features of the incoming plate. Instead, splay faults in the upper plate seem to have limited rupture propagation in the updip and along-strike directions. Additionally, we found that along-strike gradients in slip are spatially correlated with geometrical inflections of the megathrust. Our study suggests that persistent tectonic features may control strain accumulation and release along subduction megathrusts. KW - GPS KW - Chile KW - Maule KW - slip model KW - FEM Y1 - 2012 U6 - https://doi.org/10.1016/j.epsl.2012.01.006 SN - 0012-821X VL - 321 IS - 3 SP - 152 EP - 165 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Melnick, Daniel A1 - Moreno, Marcos A1 - Quinteros, Javier A1 - Carlos Baez, Juan A1 - Deng, Zhiguo A1 - Li, Shaoyang A1 - Oncken, Onno T1 - The super-interseismic phase of the megathrust earthquake cycle in Chile JF - Geophysical research letters N2 - Along a subduction zone, great megathrust earthquakes recur either after long seismic gaps lasting several decades to centuries or over much shorter periods lasting hours to a few years when cascading successions of earthquakes rupture nearby segments of the fault. We analyze a decade of continuous Global Positioning System observations along the South American continent to estimate changes in deformation rates between the 2010 Maule (M8.8) and 2015 Illapel (M8.3) Chilean earthquakes. We find that surface velocities increased after the 2010 earthquake, in response to continental-scale viscoelastic mantle relaxation and to regional-scale increased degree of interplate locking. We propose that increased locking occurs transiently during a super-interseismic phase in segments adjacent to a megathrust rupture, responding to bending of both plates caused by coseismic slip and subsequent afterslip. Enhanced strain rates during a super-interseismic phase may therefore bring a megathrust segment closer to failure and possibly triggered the 2015 event. KW - megathrust KW - earthquake KW - cycle KW - Chile Y1 - 2017 U6 - https://doi.org/10.1002/2016GL071845 SN - 0094-8276 SN - 1944-8007 VL - 44 IS - 2 SP - 784 EP - 791 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Tolorza, Violeta A1 - Mohr, Christian Heinrich A1 - Carretier, Sebastien A1 - Serey, Amador A1 - Sepulveda, Sergio A. A1 - Tapia, Joseline A1 - Pinto, Luisa T1 - Suspended sediments in chilean rivers reveal low postseismic erosion after the maule earthquake (Mw 8.8) during a severe drought JF - Journal of geophysical research : Earth surface N2 - We address the question of whether all large-magnitude earthquakes produce an erosion peak in the subaerial components of fluvial catchments. We evaluate the sediment flux response to the Maule earthquake in the Chilean Andes (Mw 8.8) using daily suspended sediment records from 31 river gauges. The catchments cover drainage areas of 350 to around 10,000 km(2), including a wide range of topographic slopes and vegetation cover of the Andean western flank. We compare the 3- to 8-year postseismic record of sediment flux to each of the following preseismic periods: (1) all preseismic data, (2) a 3-year period prior to the seismic event, and (3) the driest preseismic periods, as drought conditions prevailed in the postseismic period. Following the earthquake, no increases in suspended sediment flux were observed for moderate to high percentiles of the streamflow distribution (mean, median, and >= 75th percentile). However, more than half of the examined stations showed increased sediment flux during baseflow. By using a Random Forest approach, we evaluate the contributions of seismic intensities, peak ground accelerations, co-seismic landslides, hydroclimatic conditions, topography, lithology, and land cover to explain the observed changes in suspended sediment concentration and fluxes. We find that the best predictors are hillslope gradient, low-vegetation cover, and changes in streamflow discharge. This finding suggests a combined first-order control of topography, land cover, and hydrology on the catchment-wide erosion response. We infer a reduced sediment connectivity due to the postseismic drought, which increased the residence time of sediment detached and remobilized following the Maule earthquake. KW - earthquake KW - suspended sediment KW - Maule megathrust KW - Chile KW - catchment Y1 - 2019 U6 - https://doi.org/10.1029/2018JF004766 SN - 2169-9003 SN - 2169-9011 VL - 124 IS - 6 SP - 1378 EP - 1397 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Iturrizaga, Lasafam A1 - Charrier G., Reynaldo T1 - Sudden glacier advances in the Cachapoal Valley, Southern Central Andes of Chile (34 degrees S) JF - Journal of South American earth sciences N2 - Throughout the Andes Mountains of South America, a general trend of glacier shrinkage has taken place in modern times. However, a few glaciers have undergone considerable temporally advances or even surged during the mid-19th to 20th century CE. These valley glaciers are mainly located in the Central Andes of Chile and Argentina. The research presented here focuses on the changes of the Cachapoal Glacier in the Southern Central Andes of Chile. Spectacular glacier advances occurred at least three times in historical times, which lead to river blockages and successive lake outburst floods. The glacier advances were reconstructed with a multi-method approach including geomorphological mapping, Be-10 cosmogenic exposure dating of moraines, multi-temporal comparison of historical and recent photographs and paintings as well as the interpretation of aerial photographs and satellite images and the analysis of early travel reports. The article highlights the diversity of environmental conditions for the formation of glaciers in terms of the topographical and climatic setting and the resulting distinct glacier behavior along the Andes Mountains. It is argued for the Cachapoal Glacier that the glacier advances are intrinsic to the glacier type and may not be necessarily climate-dependent. This is characteristic for avalanche-fed glaciers of which the glacier dynamic is strongly controlled by the topographic setting and sudden inputs of ice and rock avalanches as well as by the specific debris transfer system and hydrological drainage pattern. At the regional level, the fluctuations of the Cachapoal Glacier are compared with glaciers of neighboring mountain ranges in the Southern Central Andes and at the global scale with those of the Karakoram Mountains in High Asia with a similar dynamic glacier behavior. KW - Cachapoal Glacier KW - Glacier surges KW - Topography-controlled glacier KW - advances KW - Glacier lake outbursts KW - Debris-covered glaciers KW - Central KW - Andes KW - Chile Y1 - 2021 U6 - https://doi.org/10.1016/j.jsames.2020.102787 SN - 0895-9811 SN - 1873-0647 VL - 105 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Mohr, Christian Heinrich A1 - Manga, Michael A1 - Wald, David T1 - Stronger peak ground motion, beyond the threshold to initiate a response, does not lead to larger stream discharge responses to earthquakes JF - Geophysical research letters N2 - The impressive number of stream gauges in Chile, combined with a suite of past and recent large earthquakes, makes Chile a unique natural laboratory to study several streams that recorded responses to multiple seismic events. We document changes in discharge in eight streams in Chile following two or more large earthquakes. In all cases, discharge increases. Changes in discharge occur for peak ground velocities greater than about 7-11cm/s. Above that threshold, the magnitude of both the increase in discharge and the total excess water do not increase with increasing peak ground velocities. While these observations are consistent with previous work in California, they conflict with lab experiments that show that the magnitude of permeability changes increases with increasing amplitude of ground motion. Instead, our study suggests that streamflow responses are binary. Plain Language Summary Earthquakes deform and shake the surface and the ground below. These changes may affect groundwater flows by increasing the permeability along newly formed cracks and/or clearing clogged pores. As a result, groundwater flow may substantially increase after earthquakes and remain elevated for several months. Here we document streamflow anomalies following multiple high magnitude earthquakes in multiple streams in one of the most earthquake prone regions worldwide, Chile. We take advantage of the dense monitoring network in Chile that recorded streamflow since the 1940s. We show that once a critical ground motion is exceeded, streamflow responses to earthquakes can be expected. KW - earthquake KW - streamflow KW - shaking KW - Chile KW - modeling Y1 - 2018 U6 - https://doi.org/10.1029/2018GL078621 SN - 0094-8276 SN - 1944-8007 VL - 45 IS - 13 SP - 6523 EP - 6531 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Ulloa, H. A1 - Iroume, A. A1 - Picco, L. A1 - Mohr, Christian Heinrich A1 - Mazzorana, B. A1 - Lenzi, Mario Aristide A1 - Mao, L. T1 - Spatial analysis of the impacts of the Chaiten volcano eruption (Chile) in three fluvial systems JF - Journal of South American earth sciences N2 - The eruption of the Chaiten volcano in May 2008 generated morphological and ecological disturbances in adjacent river basins, and the magnitude of these disturbances depended on the type of dominant volcanic process affecting each of them. The aim of this study is to analyse the morphological changes in different periods in river segments of the Blanco, El Amarillo and Rayas river basins located near the Chaiten volcano. These basins suffered disturbances of different intensity and spatial distribution caused by tephra fall, dome collapses and pyroclastic density currents that damaged hillslope forests, widened channels and destroyed island and floodplain vegetation. Changes continued to occur in the fluvial systems in the years following the eruption, as a consequence of the geomorphic processes indirectly induced by the eruption. Channel changes were analyzed by comparing remote images of pre and post eruption conditions. Two periods were considered: the first from 2008 to 2009-2010 associated with the explosive and effusive phases of the eruption and the second that correspond to the post-eruption stage from 2009-2010 to 2013. Following the first phases channel segments widened 91% (38 m/yr), 6% (7 m/yr) and 7% (22 m/yr) for Blanco, Rayas and El Amarillo Rivers, respectively, compared to pre-eruption condition. In the second period, channel segments additionally widened 42% (8 m/yr), 2% (2 m/yr) and 5% (4 m/yr) for Blanco, Rayas and El Amarillo Rivers, respectively. In the Blanco River 62 and 82% of the islands disappeared in the first and second period, respectively, which is 6-8 times higher than in the El Amarillo approximately twice the Rayas. Sinuosity increased after the eruption only in the Blanco River but the three study channels showed a high braiding intensity mainly during the first post-eruption period. The major disturbances occurred during the eruptive and effusive phases of Chaiten volcano, and the intensity of these disturbances reflects the magnitude of the dominant volcanic processes affecting each basin. Inputs of sediment from dome collapses and pyroclastic density currents and not ash fall seem to explain morphologic channel change magnitudes in the study segments. The resulting knowledge can facilitate land use planning and design of river restoration projects in areas affected by volcanic eruptions disturbances. (C) 2016 Elsevier Ltd. All rights reserved. KW - Volcanic disturbances KW - Changes in fluvial systems KW - Island KW - Riparian vegetation KW - Chaiten volcano KW - Chile Y1 - 2016 U6 - https://doi.org/10.1016/j.jsames.2016.04.008 SN - 0895-9811 VL - 69 SP - 213 EP - 225 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Schuster, Isabell A1 - Krahé, Barbara A1 - Ilabaca Baeza, Paola A1 - Munoz-Reyes, Jose A. T1 - Sexual Aggression Victimization and Perpetration among Male and Female College Students in Chile JF - Frontiers in psychology N2 - Evidence on the prevalence of sexual aggression among college students is primarily based on studies from Western countries. In Chile, a South American country strongly influenced by the Catholic Church, little research on sexual aggression among college students is available. Therefore, the purpose of the present study was to examine the prevalence of sexual aggression victimization and perpetration since the age of 14 (the legal age of consent) in a sample of male and female students aged between 18 and 29 years from five Chilean universities (N = 1135), to consider possible gender differences, and to study the extent to which alcohol was involved in the reported incidents of perpetration and victimization. Sexual aggression victimization and perpetration was measured with a Chilean Spanish version of the Sexual Aggression and Victimization Scale (SAV-S), which includes three coercive strategies (use or threat of physical force, exploitation of an incapacitated state, and verbal pressure), three victim-perpetrator constellations (current or former partners, friends/acquaintances, and strangers), and four sexual acts (sexual touch, attempted sexual intercourse, completed sexual intercourse, and other sexual acts, such as oral sex). Overall, 51.9% of women and 48.0% of men reported at least one incident of sexual victimization, and 26.8% of men and 16.5% of women reported at least one incident of sexual aggression perpetration since the age of 14. For victimization, only few gender differences were found, but significantly more men than women reported sexual aggression perpetration. A large proportion of perpetrators also reported victimization experiences. Regarding victim-perpetrator relationship, sexual aggression victimization and perpetration were more common between persons who knew each other than between strangers. Alcohol use by the perpetrator, victim, or both was involved in many incidents of sexual aggression victimization and perpetration, particularly among strangers. The present data are the first to provide a systematic and detailed picture of sexual aggression among college students in Chile, including victimization and perpetration reports by both men and women and confirming the critical role of alcohol established in past research from Western countries. KW - sexual aggression KW - victimization KW - perpetration KW - prevalence KW - coercive strategies KW - relationship constellations KW - alcohol KW - Chile Y1 - 2016 U6 - https://doi.org/10.3389/fpsyg.2016.01354 SN - 1664-1078 VL - 7 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Schuster, Isabell A1 - Krahé, Barbara A1 - Ilabaca Baeza, Paola A1 - Munoz-Reyes, Jose Antonio T1 - Sexual Aggression Victimization and Perpetration among Male and Female College Students in Chile JF - Frontiers in psychology N2 - Evidence on the prevalence of sexual aggression among college students is primarily based on studies from Western countries. In Chile, a South American country strongly influenced by the Catholic Church, little research on sexual aggression among college students is available. Therefore, the purpose of the present study was to examine the prevalence of sexual aggression victimization and perpetration since the age of 14 (the legal age of consent) in a sample of male and female students aged between 18 and 29 years from five Chilean universities (N = 1135), to consider possible gender differences, and to study the extent to which alcohol was involved in the reported incidents of perpetration and victimization. Sexual aggression victimization and perpetration was measured with a Chilean Spanish version of the Sexual Aggression and Victimization Scale (SAV-S), which includes three coercive strategies (use or threat of physical force, exploitation of an incapacitated state, and verbal pressure), three victim-perpetrator constellations (current or former partners, friends/acquaintances, and strangers), and four sexual acts (sexual touch, attempted sexual intercourse, completed sexual intercourse, and other sexual acts, such as oral sex). Overall, 51.9% of women and 48.0% of men reported at least one incident of sexual victimization, and 26.8% of men and 16.5% of women reported at least one incident of sexual aggression perpetration since the age of 14. For victimization, only few gender differences were found, but significantly more men than women reported sexual aggression perpetration. A large proportion of perpetrators also reported victimization experiences. Regarding victim-perpetrator relationship, sexual aggression victimization and perpetration were more common between persons who knew each other than between strangers. Alcohol use by the perpetrator, victim, or both was involved in many incidents of sexual aggression victimization and perpetration, particularly among strangers. The present data are the first to provide a systematic and detailed picture of sexual aggression among college students in Chile, including victimization and perpetration reports by both men and women and confirming the critical role of alcohol established in past research from Western countries. KW - sexual aggression KW - victimization KW - perpetration KW - prevalence KW - coercive strategies KW - relationship constellations KW - alcohol KW - Chile Y1 - 2016 U6 - https://doi.org/10.3389/fpsyg.2016.01354 SN - 1664-1078 VL - 7 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Mohr, Christian Heinrich A1 - Korup, Oliver A1 - Ulloa, Hector A1 - Iroume, Andres T1 - Pyroclastic Eruption Boosts Organic Carbon Fluxes Into Patagonian Fjords JF - Global biogeochemical cycles N2 - Fjords and old-growth forests store large amounts of organic carbon. Yet the role of episodic disturbances, particularly volcanic eruptions, in mobilizing organic carbon in fjord landscapes covered by temperate rainforests remains poorly quantified. To this end, we estimated how much wood and soils were flushed to nearby fjords following the 2008 eruption of Chaiten volcano in south-central Chile, where pyroclastic sediments covered >12km(2) of pristine temperate rainforest. Field-based surveys of forest biomass, soil organic content, and dead wood transport reveal that the reworking of pyroclastic sediments delivered similar to 66,500+14,600/-14,500tC of large wood to two rivers entering the nearby Patagonian fjords in less than a decade. A similar volume of wood remains in dead tree stands and buried beneath pyroclastic deposits (similar to 79,900+21,100/-16,900tC) or stored in active river channels (5,900-10,600tC). We estimate that bank erosion mobilized similar to 132,300(+21,700)/(-30,600)tC of floodplain forest soil. Eroded and reworked forest soils have been accreting on coastal river deltas at >5mmyr(-1) since the eruption. While much of the large wood is transported out of the fjord by long-shore drift, the finer fraction from eroded forest soils is likely to be buried in the fjords. We conclude that the organic carbon fluxes boosted by rivers adjusting to high pyroclastic sediment loads may remain elevated for up to a decade and that Patagonian temperate rainforests disturbed by excessive loads of pyroclastic debris can be episodic short-lived carbon sources. Plain Language Summary Fjords and old-growth forests are important sinks of organic carbon. However, the role of volcanic eruptions in flushing organic carbon in fjord landscapes remains unexplored. Here we estimated how much forest vegetation and soils were lost to fjords following the 2008 eruption ofunknownChaiten volcano in south-central Chile. Pyroclastic sediments obliterated near-pristine temperateunknownrainforest, and the subsequent reworking of these sediments delivered in less than a decade similar to 66,000 tC of large wood to the mountain rivers, draining into the nearby Patagonian fjords. A similar volume of wood remains in dead tree stands and buried beneath pyroclastic deposits or stored in active riverunknownchannels. We estimate that similar to 130,000 tC of organic carbon-rich soil was lost to erosion, thus adding to the carbon loads. While much of the wood enters the long-shore drift in the fjord heads, the finerunknownfraction from eroded forest soils is likely to be buried in the fjords at rates that exceed regional estimates by an order of magnitude. We anticipate that these eruption-driven fluxes will remain elevated forunknownthe coming years and that Patagonian temperate rainforests episodically switch from carbon sinks to hitherto undocumented carbon sources if disturbed by explosive volcanic eruptions. KW - Chile KW - Patagonia KW - rainforest KW - volcanic eruption KW - organic carbon KW - biomass Y1 - 2017 U6 - https://doi.org/10.1002/2017GB005647 SN - 0886-6236 SN - 1944-9224 VL - 31 SP - 1626 EP - 1638 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Schuster, Isabell A1 - Krahe, Barbara T1 - Predictors of sexual aggression perpetration among male and female college students BT - Cross-Cultural Evidence From Chile and Turkey JF - Sexual abuse : official journal of the Association for the Treatment of Sexual Abusers (ATSA) N2 - This two-wave longitudinal study examined risky sexual scripts and sexual behavior regarding consensual sexual interactions, sexual self-esteem, initiation assertiveness, and religiosity as predictors of sexual aggression perpetration in a cross-cultural comparison of college students in Chile and Turkey. As predicted, risky sexual scripts were linked to higher odds of perpetration through more risky sexual behavior cross-sectionally in both the Chilean and the Turkish sample and indirectly predicted perpetration 12 months later. High sexual self-esteem increased the likelihood of perpetration via higher initiation assertiveness in the Turkish sample only. High religiosity reduced the odds of perpetration through less risky sexual scripts and less risky sexual behavior in both samples. In addition, high religiosity increased the probability of perpetration through lower sexual self-esteem in the Turkish sample. Implications of these findings and the role of cultural factors contributing to the differential functioning of religiosity and sexual self-esteem are discussed. KW - sexual aggression perpetration KW - risk factors KW - sexual scripts KW - Chile KW - Turkey Y1 - 2019 U6 - https://doi.org/10.1177/1079063218793632 SN - 1079-0632 SN - 1573-286X VL - 31 IS - 3 SP - 318 EP - 343 PB - Sage CY - Thousand Oaks ER - TY - JOUR A1 - Schuster, Isabell A1 - Krahe, Barbara T1 - Predicting Sexual Victimization Among College Students in Chile and Turkey: A Cross-Cultural Analysis JF - Archives of sexual behavior : the official publication of the International Academy of Sex Research KW - Sexual victimization KW - Sexual scripts KW - Religiosity KW - Chile KW - Turkey Y1 - 2019 U6 - https://doi.org/10.1007/s10508-018-1335-z SN - 0004-0002 SN - 1573-2800 VL - 48 IS - 8 SP - 2565 EP - 2580 PB - Springer CY - New York ER - TY - JOUR A1 - Bernhardt, Anne A1 - Schwanghart, Wolfgang A1 - Hebbeln, Dierk A1 - Stuut, Jan-Berend W. A1 - Strecker, Manfred T1 - Immediate propagation of deglacial environmental change to deep-marine turbidite systems along the Chile convergent margin JF - Earth & planetary science letters N2 - Understanding how Earth-surface processes respond to past climatic perturbations is crucial for making informed predictions about future impacts of climate change on sediment "uxes. Sedimentary records provide the archives for inferring these processes, but their interpretation is compromised by our incomplete understanding of how sediment-routing systems respond to millennial-scale climate cycles. We analyzed seven sediment cores recovered from marine turbidite depositional sites along the Chile continental margin. The sites span a pronounced arid-to-humid gradient with variable relief and related sediment connectivity of terrestrial and marine environments. These sites allowed us to study event related depositional processes in different climatic and geomorphic settings from the Last Glacial Maximum to the present day. The three sites reveal a steep decline of turbidite deposition during deglaciation. High rates of sea-level rise postdate the decline in turbidite deposition. Comparison with paleoclimate proxies documents that the spatio-temporal sedimentary pattern rather mirrors the deglacial humidity decrease and concomitant warming with no resolvable lag times. Our results let us infer that declining deglacial humidity decreased "uvial sediment supply. This signal propagated rapidly through the highly connected systems into the marine sink in north-central Chile. In contrast, in south-central Chile, connectivity between the Andean erosional zone and the "uvial transfer zone probably decreased abruptly by sediment trapping in piedmont lakes related to deglaciation, resulting in a sudden decrease of sediment supply to the ocean. Additionally, reduced moisture supply may have contributed to the rapid decline of turbidite deposition. These different causes result in similar depositional patterns in the marine sinks. We conclude that turbiditic strata may constitute reliable recorders of climate change across a wide range of climatic zones and geomorphic conditions. However, the underlying causes for similar signal manifestations in the sinks may differ, ranging from maintained high system connectivity to abrupt connectivity loss. (C) 2017 Elsevier B.V. All rights reserved. KW - signal propagation KW - turbidity currents KW - Chile KW - sediment-routing system connectivity KW - Last Glacial Maximum Y1 - 2017 U6 - https://doi.org/10.1016/j.epsl.2017.05.017 SN - 0012-821X SN - 1385-013X VL - 473 SP - 190 EP - 204 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Moreno, Marcelo Spegiorin A1 - Melnick, Daniel A1 - Rosenau, M. A1 - Bolte, John A1 - Klotz, Jan A1 - Echtler, Helmut Peter A1 - Báez, Juan Carlos A1 - Bataille, Klaus A1 - Chen, J. A1 - Bevis, M. A1 - Hase, H. A1 - Oncken, Onno T1 - Heterogeneous plate locking in the South-Central Chile subduction zone building up the next great earthquake JF - Earth & planetary science letters N2 - We use Global Positioning System (GPS) velocities and kinematic Finite Element models (FE-models) to infer the state of locking between the converging Nazca and South America plates in South-Central Chile (36 degrees S -46 degrees S) and to evaluate its spatial and temporal variability. GPS velocities provide information on earthquake-cycle deformation over the last decade in areas affected by the megathrust events of 1960 (M-w = 9.5) and 2010 (M-w = 8.8). Our data confirm that a change in surface velocity patterns of these two seismotectonic segments can be related to their different stages in the seismic cycle: Accordingly, the northern (2010) segment was in a final stage of interseismic loading whereas the southern (1960) segment is still in a postseismic stage and undergoes a prolonged viscoelastic mantle relaxation. After correcting the signals for mantle relaxation, the residual GPS velocity pattern suggests that the plate interface accumulates slip deficit in a spatially and presumably temporally variable way towards the next great event. Though some similarity exist between locking and 1960 coseismic slip, extrapolating the current, decadal scale slip deficit accumulation towards the similar to 300-yr recurrence times of giant events here does neither yield the slip distribution nor the moment magnitude of the 1960 earthquake. This suggests that either the locking pattern is evolving in time (to reconcile a slip deficit distribution similar to the 1960 earthquake) or that some asperities are not persistent over multiple events. The accumulated moment deficit since 1960 suggests that highly locked patches in the 1960 segment are already capable of producing a M similar to 8 event if triggered to fail by stress transfer from the 2010 event. KW - GPS KW - Chile KW - Maule KW - locking degree KW - postseismic deformation KW - earthquake cycle Y1 - 2011 U6 - https://doi.org/10.1016/j.epsl.2011.03.025 SN - 0012-821X VL - 305 IS - 3-4 SP - 413 EP - 424 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Melnick, Daniel A1 - Cisternas, Marco A1 - Moreno, Marcos A1 - Norambuena, Ricardo T1 - Estimating coseismic coastal uplift with an intertidal mussel calibration for the 2010 Maule Chile earthquake (M-w=8.8) JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - Coseismic coastal uplift has been quantified using sessile intertidal organisms after several great earthquakes following FitzRoy's pioneer measurements in 1835. A dense survey of such markers may complement space geodetic data to obtain an accurate distribution of fault slip and earthquake segmentation. However, uplift estimates based on diverse intertidal organisms tend to differ, because of few methodological and comparative studies. Here, we calibrate and estimate coastal uplift in the southern segment of the 2010 Maule, Chile earthquake (M-w = 8.8) using > 1100 post-earthquake elevation measurements of the sessile mussel Perumytilus purpuratus. This mussel is the predominant competitor for rocky shores all along the Pacific coast of South America, where it forms fringes or belts distinctively in the middle intertidal zone. These belts are centered at mean sea level and their width should equal one third of the tidal range. We measured belt widths close to this value at 40% of the sites, but overall widths are highly variable due to the unevenness in belt tops; belt bases, in turn, are rather regular. Belt top unevenness apparently results from locally-enhanced wave splash, whereas belt base evenness is controlled by predation. According to our measurements made beyond the earthquake rupture, the belt base is at the bottom of the middle intertidal zone, and thus we propose to estimate coastal uplift using the belt base mean elevation plus one sixth of the tidal range to reach mean sea level. Within errors our estimates agree with GPS displacements but differ from other methods. Comparisons of joint inversions for megathrust slip suggest combining space geodetic data with estimates from intertidal organisms may locally increase the detail of slip distributions. KW - Coastal uplift KW - Maule earthquake KW - Chile KW - Intertidal organisms KW - Perumytilus mussels KW - Slip distribution Y1 - 2012 U6 - https://doi.org/10.1016/j.quascirev.2012.03.012 SN - 0277-3791 VL - 42 IS - 5 SP - 29 EP - 42 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Oeser, Ralf Andreas A1 - Stroncik, Nicole A1 - Moskwa, Lisa-Marie A1 - Bernhard, Nadine A1 - Schaller, Mirjam A1 - Canessa, Rafaella A1 - van den Brink, Liesbeth A1 - Köster, Moritz A1 - Brucker, Emanuel A1 - Stock, Svenja A1 - Pablo Fuentes, Juan A1 - Godoy, Roberto A1 - Javier Matus, Francisco A1 - Oses Pedraza, Romulo A1 - Osses McIntyre, Pablo A1 - Paulino, Leandro A1 - Seguel, Oscar A1 - Bader, Maaike Y. A1 - Boy, Jens A1 - Dippold, Michaela A. A1 - Ehlers, Todd A1 - Kühn, Peter A1 - Kuzyakov, Yakov A1 - Leinweber, Peter A1 - Scholten, Thomas A1 - Spielvogel, Sandra A1 - Spohn, Marie A1 - Ubernickel, Kirstin A1 - Tielbörger, Katja A1 - Wagner, Dirk A1 - von Blanckenburg, Friedhelm T1 - Chemistry and microbiology of the Critical Zone along a steep climate and vegetation gradient in the Chilean Coastal Cordillera JF - Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution N2 - From north to south, denudation rates from cosmogenic nuclides are similar to 10 t km(-2) yr(-1) at the arid Pan de Aziicar site, similar to 20 t km(2) yr(-1) at the semi-arid site of Santa Gracia, -60 t km(-2) yr(-1) at the Mediterranean climate site of La Campana, and similar to 30 t km(-2) yr(-1) at the humid site of Nahuelbuta. A and B horizons increase in thickness and elemental depletion or enrichment increases from north (similar to 26 degrees S) to south (similar to 38 degrees S) in these horizons. Differences in the degree of chemical weathering, quantified by the chemical depletion fraction (CDF), are significant only between the arid and sparsely vegetated site and the other three sites. Differences in the CDF between the sites, and elemental depletion within the sites are sometimes smaller than the variations induced by the bedrock heterogeneity. Microbial abundances (bacteria and archaea) in saprolite substantially increase from the arid to the semi-arid sites. With this study, we provide a comprehensive dataset characterizing the Critical Zone geochemistry in the Chilean Coastal Cordillera. This dataset confirms climatic controls on weathering and denudation rates and provides prerequisites to quantify the role of biota in future studies. KW - Weathering KW - Denudation KW - Microbial abundance KW - Climate KW - Chile Y1 - 2018 U6 - https://doi.org/10.1016/j.catena.2018.06.002 SN - 0341-8162 SN - 1872-6887 VL - 170 SP - 183 EP - 203 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Korup, Oliver A1 - Mohr, Christian Heinrich A1 - Manga, Michael M. T1 - Bayesian detection of streamflow response to earthquakes JF - Water resources research : an AGU journal N2 - Detecting whether and how river discharge responds to strong earthquake shaking can be time-consuming and prone to operator bias when checking hydrographs from hundreds of gauging stations. We use Bayesian piecewise regression models to show that up to a fifth of all gauging stations across Chile had their largest change in daily streamflow trend on the day of the M-w 8.8 Maule earthquake in 2010. These stations cluster distinctly in the near field though the number of detected streamflow changes varies with model complexity and length of time window considered. Credible seismic streamflow changes at several stations were the highest detectable in eight months, with an increased variance of discharge surpassing the variance of discharge following rainstorms. We conclude that Bayesian piecewise regression sheds new and unbiased insights on the duration, trend, and variance of streamflow response to strong earthquakes, and on how this response compares to that following rainstorms. KW - Bayesian analysis KW - Chile KW - discharge KW - earthquake KW - streamflow changes Y1 - 2021 U6 - https://doi.org/10.1029/2020WR028874 SN - 0043-1397 SN - 1944-7973 VL - 57 IS - 7 PB - Wiley CY - Hoboken, NJ ER -