<i>P</i>-wave velocity structure beneath the northern Antarctic Peninsula: evidence of a steeply subducting slab and a deep-rooted low-velocity anomaly beneath the central Bransfield Basin

Park, Yongcheol; Kim, Kwanghee; Lee, Joohan; Yoo, Hyung Joun; Plasencia, P L Milton

doi:10.1111/j.1365-246x.2012.05684.x

Cited by 11 publications

(20 citation statements)

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“…This view supports the hypothesis that the Bransfield Basin is the product of back-arc spreading, which is also supported by the deformation and overthrusting of the youngest trench fill sediments in the SST (Jabaloy et al, 2003) and by magnetic and gravimetric models (Yegorova et al, 2010). In a more recent paper, Park et al (2012) use P-wave tomography to image the structure below the SSB. Results show a positive anomaly in seismic velocity, indicating the position of a steeply dipping subducting slab which the authors suggest is causing slab pull and, therefore, back-arc extension.…”

Section: Tectonic Settingsupporting

confidence: 66%

“…To the north, the Shetland plate is bounded by the Scotia plate from the Shetland-Antarctic-Scotia triple junction to the SFZ. From the SFZ to the Hero Fracture Zone (HFZ) the Shetland plate bounds with Phoenix through the SST, where Phoenix is thought to be passively sinking (Ibáñez et al, 1997;Jabaloy et al, 2003;Robertson Maurice et al, 2003;Dziak et al, 2010;Yegorova et al, 2010;Park et al, 2012), although the current activity of the subduction is under debate (González-Casado et al, 2000;Jin et al, 2009). In the Bransfield Basin there is evidence of seafloor spreading through seamount volcanism and of prespreading back-arc rifting (Gràcia et al, 1996), although it has not yet evolved to the formation of normal oceanic crust (Lawver et al, 1996;Christeson et al, 2003).…”

Section: Tectonic Settingmentioning

confidence: 99%

“…1) located immediately to the northwest of the SSI has been a focus of interest in past years, as the presence of an active subduction has been largely debated. The most recent seismic studies support the presence of a slowly sinking slab below the region (Robertson Maurice et al, 2003;Dziak et al, 2010;Park et al, 2012) which would be responsible, at least partially, of the active rifting in the Bransfield Basin. In this seismically active region the occurrence of earthquakes responding to such processes provide evidence of a complex tectonic setting (Robertson Maurice et al, 2003, see Fig.…”

Section: Introductionmentioning

confidence: 99%

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Structure of the crust and upper mantle beneath the Bransfield Strait (Antarctica) using P receiver functions

Portell¹

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B Time-domain stacks xiv C H-κ stacks xxiI would like to acknowledge my two supervisors, Flor de Lis Mancilla and José Morales, for their help and support, as well as for all the hours I spent with Flor discussing the results and resolving my (many) questions and doubts. In addition, they gave me the opportunity to write this thesis at the Instituto Andaluz de Geofísica (IAG) in a very friendly environment.My gratitude to anyone whom I spent time with at the IAG, including the GEOMET professors and the fellow students Eugènia and Saray; I have felt very comfortable. Special thanks to Roberto for the time we shared working together and discussing both this thesis and his.

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Section: Tectonic Settingsupporting

confidence: 66%

Section: Tectonic Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structure of the crust and upper mantle beneath the Bransfield Strait (Antarctica) using P receiver functions

Portell¹

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“…With these concerns, tectonic activities have been found to continue around WARS until now. Moreover, P-wave travel-time tomography research obtained three-dimensional velocity structure of the Bransfield Strait (BFS) by using the data from both the temporary and permanent networks in the northern Antarctic Peninsula [18]. The tomography result imaged the presence of steeply subducting oceanic plate (slab, the Phoenix Plate) under BFS, as well as strong low-velocity anomalies in the 100-300 km depths involving the formation of volcanoes inside the strait.…”

Section: Antarctic Regionmentioning

confidence: 99%

Structural Studies on the Earth’s Crust, Plates, and the Ice Sheet in the Polar Region

Kanao¹

2018

Polar Seismology - Advances and Impact

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During the International Polar Year (IPY 2007-2008), a number of seismological studies regarding the structure and dynamics of the Earth's surface layers, the static inner structure of the crystalline crust and lithosphere involving Earth's history, earthquake occurrence mechanism, inner deformation of the plates, crustal movement relating to deglaciation, seismic isotropy, and the other topics of the ice sheet overlying the solid earth were conducted. In this chapter, recent seismological results as for the structural study of the crust, plates, and ice sheet in bipolar regions are overviewed.

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“…We obtain insight on the feasibility of the direct use of Rayleigh wave dispersion curves to study the crustal structure of the Bransfield Strait and monitor seasonal velocity variations. been studied by various authors for over the last five decades (Ashcroft 1972;Janik 1997;Grad et al 1997;Christeson et al 2003;Barker et al 2003;Vuan et al 2005;Janik et al 2006;Yegorova et al 2011;Park et al 2012;Vuan et al 2014). But the details of its crustal structure has been difficult to describe and the conclusions have been controversial.…”

Section: Introductionmentioning

confidence: 99%

A Feasibility Study on Monitoring Crustal Structure Variations by Direct Comparison of Surface Wave Dispersion Curves from Ambient Seismic Noise

Muhumuza

2020

International Journal of Geophysics

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This work assesses the feasibility of the direct use of surface-wave dispersion curves from seismic ambient noise to gain insight into the crustal structure of Bransfield Strait and detect seasonal seismic velocity changes. We cross-correlated four years of vertical component ambient noise data recorded by a seismic array in West Antarctica. To estimate fundamental mode Rayleigh wave Green's functions, the correlations are computed in 4-hr segments, stacked over 1-year time windows and moving windows of 3 months. Rayleigh wave group dispersion curves are then measured on two spectral bands-primary (10-30 s) and secondary (5-10 s) microseisms-using frequency-time analysis. We analyze the temporal evolution of seismic velocity by comparing dispersion curves for the successive annual and 3-month correlation stacks. Our main assumption was that the Green's functions from the cross-correlations, and thus the dispersion curves, remain invariant if the crustal structure remains unchanged. Maximum amplitudes of secondary microseisms were observed during local winter when the Southern Ocean experiences winter storms. The Rayleigh wave group velocity ranges between 2.1 and 3.7 km/s, considering our period range studied. Inter-annual velocity variations are not much evident. We observe a slight velocity decrease in summer and increase in winter, which could be attributed to the pressure melting of ice and an increase in ice mass, respectively. The velocity anomalies observed within the crust and upper mantle structure correlate with the major crustal and upper mantle features known from previous studies in the area. Our results demonstrate that the direct comparison of surface wave dispersion curves extracted from ambient noise might be a useful tool in monitoring crustal structure variations.In this study, we used vertical component continuous seismic data from 4 stations in the Argentine Antarctica region from ASAIN (Antarctic Seismographic Argentine-Italian Network) in West Antarctica (Fig. 1). The stations Carlini-formerly Jubany (JUBA)-station, Esperanza (ESPZ), Orcada (ORCD) and San Martin (SMAI) are part of the 5 seismological stations that have been set under ASAIN collaborative agreement.The seismologic network provide essential data to study the internal structure of the Antarctic continent, monitor seismicity, and to monitor large-scale phenomena, such as melting of the Antarctic ice sheet, among others. We analyzed 4 years (2008-2011) of seismic data recorded recorded by the 4 stations with a sampling rate of 1 sample per second. The initial data preparation involves unpacking the raw data from its standard SEED format to obtain noise data in SAC format. We have to ensure that the two amplitudes of each record are completely consistent by running a time normalization so that the records share the same absolute time and the same amplitude information is retained. It is important to note that if the instruments of two stations are inconsistent, it is necessary to remove instrument responses from the raw data.Here ...

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P-wave velocity structure beneath the northern Antarctic Peninsula: evidence of a steeply subducting slab and a deep-rooted low-velocity anomaly beneath the central Bransfield Basin

Cited by 11 publications

References 58 publications

Structure of the crust and upper mantle beneath the Bransfield Strait (Antarctica) using P receiver functions

Structure of the crust and upper mantle beneath the Bransfield Strait (Antarctica) using P receiver functions

Structural Studies on the Earth’s Crust, Plates, and the Ice Sheet in the Polar Region

A Feasibility Study on Monitoring Crustal Structure Variations by Direct Comparison of Surface Wave Dispersion Curves from Ambient Seismic Noise

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