Post-Seismic Deformation in the Northern Antarctic Peninsula Following the 2013 Magnitude 7.7 Scotia Sea Earthquake

Large earthquakes in the vicinity of Antarctica have the potential to cause post-seismic deformation on the continent, affecting measurements of displacement and gravity field change from GRACE or those attempting to constrain models of glacial isostatic adjustment.In November 2013 a magnitude 7.7 strike-slip earthquake occurred in the Scotia Sea around 650 km from the northern tip of the Antarctic Peninsula. GPS coordinate time series from the Peninsula region show a change in rate after this event indicating a far-field post-seismic deformation signal is present. At these far-field locations, the effects of fault after-slip are likely negligible and hence we consider the deformation to be due to post-seismic viscoelastic deformation. Here we use a global spherical finite element model to investigate the extent of post-seismic viscoelastic deformation in the northern Antarctic Peninsula. We investigate possible 1D earth models that can fit the GPS data and consider the effect of including a simple 3D earth structure in the region. These results, combined with previous results showing East Antarctica is still deforming following 1998 Mw&#160;8.2 intraplate earthquake, suggest that much of Antarctica is deforming due to recent post-seismic deformation.

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Terrigenous sediment supply in the Scotia Sea (Southern Ocean): response to Late Quaternary ice dynamics in Patagonia and on the Antarctic Peninsula

Palaeogeography Palaeoclimatology Palaeoecology ◽

10.1016/s0031-0182(00)00138-3 ◽

2000 ◽

Vol 162 (3-4) ◽

pp. 357-387 ◽

Cited By ~ 72

Author(s):

Bernhard Diekmann ◽

Gerhard Kuhn ◽

Volker Rachold ◽

Andrea Abelmann ◽

Uta Brathauer ◽

...

Keyword(s):

Southern Ocean ◽

Antarctic Peninsula ◽

Late Quaternary ◽

Sediment Supply ◽

Ice Dynamics ◽

Scotia Sea ◽

Terrigenous Sediment ◽

Ocean Response ◽

The Antarctic

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Estimation of present-day glacial isostatic adjustment, ice mass change and elastic vertical crustal deformation over the Antarctic ice sheet

Journal of Glaciology ◽

10.1017/jog.2017.37 ◽

2017 ◽

Vol 63 (240) ◽

pp. 703-715 ◽

Cited By ~ 5

Author(s):

BAOJUN ZHANG ◽

ZEMIN WANG ◽

FEI LI ◽

JIACHUN AN ◽

YUANDE YANG ◽

...

Keyword(s):

Antarctic Peninsula ◽

Crustal Deformation ◽

Ice Sheet ◽

East Antarctica ◽

Mass Change ◽

Glacial Isostatic Adjustment ◽

Antarctic Ice Sheet ◽

Isostatic Adjustment ◽

The Antarctic ◽

Vertical Crustal Deformation

ABSTRACTThis study explores an iterative method for simultaneously estimating the present-day glacial isostatic adjustment (GIA), ice mass change and elastic vertical crustal deformation of the Antarctic ice sheet (AIS) for the period October 2003–October 2009. The estimations are derived by combining mass measurements of the GRACE mission and surface height observations of the ICESat mission under the constraint of GPS vertical crustal deformation rates in the spatial domain. The influence of active subglacial lakes on GIA estimates are mitigated for the first time through additional processing of ICESat data. The inferred GIA shows that the strongest uplift is found in the Amundsen Sea Embayment (ASE) sector and subsidence mostly occurs in Adelie Terre and the East Antarctica inland. The total GIA-related mass change estimates for the entire AIS, West Antarctica Ice Sheet (WAIS), East Antarctica Ice Sheet (EAIS), and Antarctic Peninsula Ice Sheet (APIS) are 43 ± 38, 53 ± 24, −23 ± 29 and 13 ± 6 Gt a−1, respectively. The overall ice mass change of the AIS is −46 ± 43 Gt a−1 (WAIS: −104 ± 25, EAIS: 77 ± 35, APIS: −20 ± 6). The most significant ice mass loss and most significant elastic vertical crustal deformations are concentrated in the ASE and northern Antarctic Peninsula.

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Glacier Fluctuations in George VI Sound Area, West Antarctica (Abstract only)

Annals of Glaciology ◽

10.1017/s0260305500003165 ◽

1982 ◽

Vol 3 ◽

pp. 345 ◽

Cited By ~ 1

Author(s):

C.M. Clapperton ◽

D.E. Sugden

Keyword(s):

Antarctic Peninsula ◽

Ice Age ◽

List Type ◽

West Antarctica ◽

Ice Shelf ◽

Scotia Sea ◽

Field Evidence ◽

Glacial Chronology ◽

History Of ◽

The Antarctic

George VI Sound lies between Alexander Island and the Antarctic Peninsula and is over 20 km wide and 500 km long. At present an ice shelf fills the sound and is nourished largely by ice from the Antarctic Peninsula which flows across the sound to ground against the coast of Alexander Island. Ice-free areas, comprising small nunataks and larger massifs, fringe both sides of the sound and contain evidence of the former glacial history of the area. This paper describes the field evidence in detail and uses geomorphological and sedimentary analyses to put forward a relative glacial chronology, constrained by two absolute dates. The chronology distinguishes: (1) a maximum state during which all ice-free areas were submerged by ice flowing into George VI Sound from both the Antarctic Peninsula and Alexander Island and thence along the sound as an ice stream. This occurred in the late Wisconsin and followed an interstadial or interglacial when George VI Sound was free of an ice shelf. (2) a valley-based stadial during overall deglaciation represented by pronounced marginal moraines on Alexander Island. (3) deglaciation to a stage where there was less landbased ice on Alexander Island than today. At this stage isostatic recovery was incomplete, relative sealevel was higher, and George VI Ice Shelf penetrated further into embayments on Alexander Island than at present. (4) probable disappearance of George VI Ice Shelf by 6.5 14C ka BP. (5) neoglacial readvance of local glaciers on Alexander Island to form three closely spaced terminal moraines and the growth of a new George VI Ice Shelf which was again more extensive than at present. (6) subsequent oscillations of both smaller Alexander Island glaciers and George VI Ice Shelf probably during the Little Ice Age. These fluctuations are similar to those in other sub-Antarctic Islands in the Scotia Sea and also in southern Chile.

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Upper mantle viscosity structure and lithospheric thickness of Antarctica inferred from recent seismic models

10.5194/egusphere-egu2020-12280 ◽

2020 ◽

Author(s):

Douglas Wiens ◽

Andrew Lloyd ◽

Weisen Shen ◽

Andrew Nyblade ◽

Richard Aster ◽

...

Keyword(s):

Antarctic Peninsula ◽

Upper Mantle ◽

Ice Sheet ◽

West Antarctica ◽

Lithospheric Thickness ◽

Isostatic Adjustment ◽

Low Viscosity ◽

Mantle Viscosity ◽

Seismic Models ◽

The Antarctic

Upper mantle viscosity structure and lithospheric thickness control the solid Earth response to variations in ice sheet loading. These parameters vary significantly across Antarctica, leading to strong regional differences in the timescale of glacial isostatic adjustment (GIA), with important implications for ice sheet models. &#160;We estimate upper mantle viscosity structure and lithospheric thickness using two new seismic models for Antarctica, which take advantage of temporary broadband seismic stations deployed across Antarctica over the past 18 years. Shen et al. [2018] use receiver functions and Rayleigh wave velocities from earthquakes and ambient noise to develop a higher resolution model for the upper 200 km beneath Central and West Antarctica, where most of the seismic stations have been deployed. Lloyd et al [2019] use full waveform adjoint tomography to invert three-component earthquake seismograms for a radially anisotropic model covering Antarctica and adjacent oceanic regions to 800 km depth. We estimate the mantle viscosity structure from seismic structure using laboratory-derived relationships between seismic velocity, temperature, and rheology. Choice of parameters for this mapping is guided in part by recent regional estimates of mantle viscosity from geodetic measurements. We also describe and compare several different methods of estimating lithospheric thickness from seismic constraints.The mantle viscosity estimates indicate regional variations of several orders of magnitude, with extremely low viscosity (< 1019 Pa s) beneath the Amundsen Sea Embayment (ASE) and the Antarctic Peninsula, consistent with estimates from GIA models constrained by GPS data. &#160;Lithospheric thickness is also highly variable, ranging from around 60 km in parts of West Antarctica to greater than 200 km beneath central East Antarctica. In East Antarctica, several prominent regions such as Dronning Maude Land and the Lambert Graben show much thinner lithosphere, consistent with Phanerozoic tectonic activity and lithospheric disruption. Thin lithosphere and low viscosity between the ASE and the Antarctic Peninsula likely result from the thermal effects of the slab window as the Phoenix-Antarctic plate boundary migrated northward during the Cenozoic. Low viscosity regions beneath the ASE and Marie Byrd Land coast connect to an offshore anomaly at depths of ~ 250 km, suggesting larger-scale thermal and geodynamic processes that may be linked to the initial Cretaceous rifting of New Zealand and Antarctica. Low mantle viscosity results in a characteristic GIA time scale on the order of several hundred years, such that isostatic adjustment occurs on the same time scale as grounding line retreat.&#160; Thus the associated rebound may lessen the effect of the marine ice sheet instability proposed for the ASE region.&#160;

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Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea

Deep Sea Research Part I Oceanographic Research Papers ◽

10.1016/j.dsr.2019.06.006 ◽

2019 ◽

Vol 150 ◽

pp. 103060 ◽

Cited By ~ 5

Author(s):

Mingshun Jiang ◽

Christopher I. Measures ◽

Katherine A. Barbeau ◽

Matthew A. Charette ◽

Sarah T. Gille ◽

...

Keyword(s):

Antarctic Peninsula ◽

Scotia Sea ◽

The Antarctic

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Reduced ice mass loss and three-dimensional viscoelastic deformation in northern Antarctic Peninsula inferred from GPS

Geophysical Journal International ◽

10.1093/gji/ggaa229 ◽

2020 ◽

Vol 222 (2) ◽

pp. 1013-1022 ◽

Cited By ~ 1

Author(s):

Nahidul Hoque Samrat ◽

Matt A King ◽

Christopher Watson ◽

Andrew Hooper ◽

Xianyao Chen ◽

...

Keyword(s):

Mass Loss ◽

Antarctic Peninsula ◽

Upper Mantle ◽

Three Dimensional ◽

Plate Motion ◽

Viscoelastic Deformation ◽

Lithospheric Thickness ◽

Isostatic Adjustment ◽

Wide Range ◽

Uplift Rates

SUMMARY We consider the viscoelastic rheology of the solid Earth under the Antarctic Peninsula due to ice mass loss that commenced after the breakup of the Larsen-B ice shelf. We extend the previous analysis of nearby continuous GPS time-series to include five additional years and the additional consideration of the horizontal components of deformation. They show strong uplift from ∼2002 to 2011 followed by reduced uplift rates to 2018. Modelling the GPS-derived uplift as a viscoelastic response to ongoing regional ice unloading from a new ice model confirms earlier estimates of low upper-mantle viscosities of ∼0.3–3 × 1018 Pa s in this region but allows a wide range of elastic lithosphere thickness. The observed and modelled north coordinate component shows little nonlinear variation due to the location of ice mass change to the east of the GPS sites. However, comparison of the observed and modelled east coordinate component constrains the upper-mantle viscosity to be less than ∼9 × 1018 Pa s, consistent with the viscosity range suggested by the uplift rates alone and providing important, largely independent, confirmation of that result. Our horizontal analysis showed only marginal sensitivity to modelled lithospheric thickness. The results for the horizontal components are sensitive to the adopted plate rotation model, with the estimate based on ITRF2014 suggesting that the sum of residual plate motion and pre-2002 glacial isostatic adjustment is likely less than ∼±0.5 mm yr−1 in the east component.

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Testing early life connectivity using otolith chemistry and particle-tracking simulations

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f10-065 ◽

2010 ◽

Vol 67 (8) ◽

pp. 1303-1315 ◽

Cited By ~ 25

Author(s):

Julian Ashford ◽

Mario La Mesa ◽

Bettina A. Fach ◽

Christopher Jones ◽

Inigo Everson

Keyword(s):

Antarctic Peninsula ◽

Early Life ◽

Large Scale ◽

Circulation Model ◽

Model Material ◽

Otolith Chemistry ◽

Larval Phase ◽

Scotia Sea ◽

South Georgia ◽

The Antarctic

We measured the otolith chemistry of adult Scotia Sea icefish ( Chaenocephalus aceratus ), a species with a long pelagic larval phase, along the Antarctic Circumpolar Current (ACC) and compared the chemistry with simulated particle transport using a circulation model. Material laid down in otolith nuclei during early life showed (i) strong heterogeneity between the Antarctic Peninsula and South Georgia consistent with a population boundary, (ii) evidence of finer-scale heterogeneity between sampling areas on the Antarctic Peninsula, and (iii) similarity between the eastern and northern shelves of South Georgia, indicating a single, self-recruiting population there. Consistent with the otolith chemistry, simulations of the large-scale circulation predicted that particles released at depths of 100–300 m on the Antarctic Peninsula shelf during spring, corresponding to hatching of icefish larvae from benthic nests, are transported in the southern ACC, missing South Georgia but following trajectories along the southern Scotia Ridge instead. These results suggest that the timing of release and position of early life stages in the water column substantially influence the direction and extent of connectivity. Used in complement, the two techniques promise an innovative approach for generating and testing predictions to resolve early dispersal and connectivity of populations related to the physical circulation of oceanic systems.

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Copepods, hydromedusae and siphonophores: Diversity and distribution in the Gerlache Strait, Antarctic Peninsula

Bulletin of Marine and Coastal Research ◽

10.25268/bimc.invemar.2021.50.suplesp.942 ◽

2021 ◽

Vol 50 (SuplEsp) ◽

pp. 169-186

Author(s):

Edgar Dorado ◽

Cristina Cedeño

Keyword(s):

Antarctic Peninsula ◽

Weddell Sea ◽

Dominant Form ◽

Scotia Sea ◽

Frequent Species ◽

Bellingshausen Sea ◽

Antarctic Expedition ◽

The Antarctic ◽

Oceanographic Conditions

Project Biodiversity and oceanographic conditions of the strait of Gerlache “Biogerlache-Antarctica”, aims to carry out the characterization of the Antarctic fauna of the strait, generating new contributions to the biological inventories of Antarctica. Present work focuses on the biodiversity of the zooplanktonic community, specifically on copepods, hydromedusae and siphonophorae collected during the III Antarctic Expedition of Colombia “Admiral Padilla” (2016-2017). Sampling was carried out in seven oceanographic stations located along the Gerlache strait, with vertical trawls between the maximum depth of the station and the surface. 4100 organisms belonging to 38 species of the phylum Arthropoda (Orders Calanoid and Cyclopoid) and 10 species of the phylum Cnidaria (Subclasses Hydroidolina and Trachylina) were identified. Copepods families with the greatest richness of genera are Aetideidae and Metridinidae, with Metridia gerlachei, Chiridius polaris and Gaetanus tenuispinosus being frequent species in more than 50 % of the stations. Identified species are common to the Antarctic Peninsula (Bellingshausen Sea, Scotia Sea and the Weddell Sea), also the range of four copepods are extended for the epipelagic and mesopelagic waters of the Gerlache Strait. Other frequent species are the hydromedusae Arctapodema sp. and Solmundella bitentaculata and the siphonophores Dimophyes arctica and Diphyes antarctica, the latter being collected in both polygastric and eudoxic forms (the dominant form in all stations).

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