Shear Wave Velocity Models Beneath Antarctic Margins Inverted by Genetic Algorithm for Teleseismic Receiver Functions

Kanao, Masaki; Shibutani, Takuo

doi:10.5772/32130

Cited by 3 publications

(3 citation statements)

References 27 publications

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“…We start by calculating the depth‐average crustal S wave velocity using the AN1‐S (An et al, ) model from the bedrock topography down to the Moho depth as determined in the previous step. Subsequently, we compile v p / v s ratios measured over Antarctica (Bayer et al, ; Finotello et al, ; Kanao & Shibutani, ; Kumar et al, ; Miyamachi et al, ) and calculate an average value of

{⟨v_{p} / v_{s}⟩}_{av} = 1.77

for the Antarctic continent to convert from average crustal v s to v p . In the final step, we employ the nonlinear conversion method by Christensen and Mooney () to obtain crustal density from the lateral P wave velocity variation.…”

Section: Initial Datamentioning

confidence: 99%

3‐D Density, Thermal, and Compositional Model of the Antarctic Lithosphere and Implications for Its Evolution

Haeger

Kaban

Tesauro

et al. 2019

Geochem Geophys Geosyst

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We create a 3-D density, temperature, and composition model of the Antarctic lithosphere using an integrative approach combining gravity, topography, and tomography data with mineral physics constraints and seismic data on crustal structures. The latter is used to create a new Moho and crustal density model. Temperature and thermal density variations are estimated based on S wave velocities from two independent tomography models (SL2013sv and AN1-S). Results of the Antarctic continent show the well-known distinction between East and West Antarctica in temperature and density to a depth of about 200 km. Incorporating compositional variations in the temperature calculations increases temperatures in depleted regions by up to 150°C, giving improved insights into thermal structures. The thickness of the lithospheric root also varies strongly between these regions, with values below 100 km in the west and above 200 km in the east. Regions with negative compositional density variations (<−0.040 g/cm 3 at 100 km), high depletion (Mg # > 91.5), and low temperatures (<800°C; central Dronning Maud Land, along the east flank of the Transantarctic Mountains) are interpreted as Precambrian cratonic fragments. Nearly undepleted lithosphere is found in the Lambert Graben and the Aurora Subglacial Basin and is attributed to Mesozoic rifting activity that has caused lithospheric rejuvenation.Plain Language Summary Antarctica remains one of the least studied areas on Earth, because large ice masses and climate conditions strongly hinder measurements. It plays an important role in global phenomena such as sea level change. In order to understand and predict these processes, we need knowledge about the heat coming from the Earth's interior. It has been recently recognized that the thermal state of the lithosphere, the rigid outer shell of the Earth, plays an important role in controlling dynamics of the ice shield and, thus, global sea level changes. Therefore, we create a model of the lithosphere describing the variation in temperature, density, and composition. Before, such models were created by using some single data set (usually seismic tomography). We employ a new integrative approach, combining several data sets to create a comprehensive 3-D model of the Antarctic lithosphere. Combination of various data sets gives more robust models than when using a single approach. Our results of the Antarctic continent show strong differences between East and West Antarctica in temperature and density to a depth of about 200 km. Regions with negative compositional density variations and low temperatures are identified within East Antarctica and are interpreted as being substantially older than the surrounding continent.

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{⟨v_{p} / v_{s}⟩}_{av} = 1.77

Section: Initial Datamentioning

confidence: 99%

3‐D Density, Thermal, and Compositional Model of the Antarctic Lithosphere and Implications for Its Evolution

Haeger

Kaban

Tesauro

et al. 2019

Geochem Geophys Geosyst

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“…For instance, seismic velocity models of the deeper part of continental crust in East Antarctica have been obtained by teleseismic waveform inversion using broadband data including from the Syowa Station (SYO) in the Lützow-Holm Bay (LHB). The velocity models were utilized to estimate physical characteristics of the rock composition of the crystallized crust based on a comparison with surface geology, microtectonics, and physical features measured by high-pressure laboratory experiments [1,2]. In addition to the permanent seismic observations at the Syowa Station, deep seismic surveys (DSS) using active seismic sources were carried out in 2000-2002 on the ice sheet at the continental margin (Mizuho Plateau).…”

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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“…Receiver function analysis is one of the effective and popular methods for study of the crust and upper mantle structures using teleseismic waveform data (e.g., Ammon, 1991;Cassidy, 1992;Dugda et al, 2005;Farra & Vinnik, 2000;Kanao & Shibutani, 2011;Langston, 1979;Owens et al, 1988;Saita et al, 2002;Suetsugu et al, 2004;Zhu & Kanamori, 2000). In the analysis it is often necessary to calculate synthetic waveforms for the structure models.…”

Section: Modelling For Receiver Function Analysismentioning

confidence: 99%

2.5-D Time-Domain Finite-Difference Modelling of Teleseismic Body Waves

Takenaka¹,

Okamoto²

2012

Seismic Waves - Research and Analysis

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Shear Wave Velocity Models Beneath Antarctic Margins Inverted by Genetic Algorithm for Teleseismic Receiver Functions

Cited by 3 publications

References 27 publications

3‐D Density, Thermal, and Compositional Model of the Antarctic Lithosphere and Implications for Its Evolution

3‐D Density, Thermal, and Compositional Model of the Antarctic Lithosphere and Implications for Its Evolution

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

2.5-D Time-Domain Finite-Difference Modelling of Teleseismic Body Waves

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