scholarly journals Probing layered arc crust in the Lesser Antilles using receiver functions

2018 ◽  
Vol 5 (11) ◽  
pp. 180764 ◽  
Author(s):  
David Schlaphorst ◽  
Elena Melekhova ◽  
J-Michael Kendall ◽  
Jon Blundy ◽  
Joan L. Latchman
Keyword(s):  
Crustal Structure ◽  
Receiver Function ◽  
Crustal Thickness ◽  
Receiver Functions ◽  
Lesser Antilles ◽  
The North ◽  
Seismological Data ◽  
History Of ◽  
Mohorovičić Discontinuity ◽  
Inversion Modelling

Oceanic arcs can provide insight into the processes of crustal growth and crustal structure. In this work, changes in crustal thickness and composition along the Lesser Antilles Arc (LAA) are analysed at 10 islands using receiver function (RF) inversions that combine seismological data with v P /v S ratios estimated based on crustal lithology. We collected seismic data from various regional networks to ensure station coverage for every major island in the LAA from Saba in the north to Grenada in the south. RFs show the subsurface response of an incoming signal assuming horizontal layering, where phase conversions highlight discontinuities beneath a station. In most regions of the Earth, the Mohorovičić discontinuity (Moho) is seismically stronger than other crustal discontinuities. However, in the LAA we observe an unusually strong along-arc variation in depth of the strongest discontinuity, which is difficult to explain by variations in crustal thickness. Instead, these results suggest that in layered crust, especially where other discontinuities have a stronger seismic contrast than the Moho, H– k stacking results can be easily misinterpreted. To circumvent this problem, an inversion modelling approach is introduced to investigate the crustal structure in more detail by building a one-dimensional velocity–depth profile for each island. Using this method, it is possible to identify any mid-crustal discontinuity in addition to the Moho. Our results show a mid-crustal discontinuity at about 10–25 km depth along the arc, with slightly deeper values in the north (Montserrat to Saba). In general, the depth of the Moho shows the same pattern with values of around 25 km (Grenada) to 35 km in the north. The results suggest differences in magmatic H 2 O content and differentiation history of each island.

Mapping crustal structure of the Nechako–Chilcotin plateau using teleseismic receiver function analysis,

2014 ◽  
Vol 51 (4) ◽  
pp. 407-417 ◽  
Author(s):  
H.S. Kim ◽  
J.F. Cassidy ◽  
S.E. Dosso ◽  
H. Kao
Keyword(s):  
Wave Velocity ◽  
Crustal Structure ◽  
Velocity Structure ◽  
Receiver Function ◽  
Function Analysis ◽  
Crustal Thickness ◽  
Receiver Functions ◽  
S Wave ◽  
Low Velocity ◽  
Velocity Models

This paper presents results of a passive-source seismic mapping study in the Nechako–Chilcotin plateau of central British Columbia, with the ultimate goal of contributing to assessments of hydrocarbon and mineral potential of the region. For the present study, an array of nine seismic stations was deployed in 2006–2007 to sample a wide area of the Nechako–Chilcotin plateau. The specific goal was to map the thickness of the sediments and volcanic cover, and the overall crustal thickness and structural geometry beneath the study area. This study utilizes recordings of about 40 distant earthquakes from 2006 to 2008 to calculate receiver functions, and constructs S-wave velocity models for each station using the Neighbourhood Algorithm inversion. The surface sediments are found to range in thickness from about 0.8 to 2.7 km, and the underlying volcanic layer from 1.8 to 4.7 km. Both sediments and volcanic cover are thickest in the central portion of the study area. The crustal thickness ranges from 22 to 36 km, with an average crustal thickness of about 30–34 km. A consistent feature observed in this study is a low-velocity zone at the base of the crust. This study complements other recent studies in this area, including active-source seismic studies and magnetotelluric measurements, by providing site-specific images of the crustal structure down to the Moho and detailed constraints on the S-wave velocity structure.

scholarly journals Crustal thickness estimation in Indonesia using receiver function method

2021 ◽  
Vol 873 (1) ◽  
pp. 012086
Author(s):  
M F Fauzi ◽  
A Anggraini ◽  
A Riyanto ◽  
D Ngadmanto ◽  
W Suryanto
Keyword(s):  
Receiver Function ◽  
Vertical Component ◽  
Crustal Thickness ◽  
Radial Component ◽  
Receiver Functions ◽  
Frequency Noise ◽  
Seismic Wave Velocity ◽  
The North ◽  
Central Java ◽  
Receiver Function Method

Abstract The existence of seismic wave velocity difference in the Earth crust and mantle creates the possibility to use earthquake data for estimating the crustal thickness utilizing the Ps conversion phase in the boundary. The radial component signal was deconvolved from the vertical component in the frequency domain to estimate receiver function for Indonesia region. We implemented the water level deconvolution techniques with a Gaussian filter of 2.5 Hz to eliminate the high frequency noise in the receiver function. The H-k stacking technique was performed to all receiver functions from each event to predict the crustal thickness and the Vp/Vs ratio below the stations. We analyzed ten azimuthally distributed teleseismic earthquakes recorded by 108 stations of BMKG. The result shows that the crustal thickness in Indonesia varies from 20 to 39.9 km. The western part of Sumatera, northern part of Sulawesi Island, and North Maluku region show generally thinner crust with value about 20 to 25 km. The North Sumatera, Central Java, and East Java show a considerably thicker crust of up to 36 km. Furthermore, our result also reveals a difference of crustal thickness about 5 km with the previous studies.

The Crustal Structure of the Eastern Marmara Region Using Receiver Function Analysis

2020 ◽  
Author(s):  
Pınar Büyükakpınar ◽  
Mustafa Aktar
Keyword(s):  
Fault Zone ◽  
Receiver Function ◽  
Function Analysis ◽  
Joint Inversion ◽  
Crustal Thickness ◽  
Receiver Functions ◽  
Gradual Transition ◽  
Marmara Region ◽  
The North ◽  
Receiver Function Analysis

<p>This study focuses on the crust of the Eastern Marmara in order to understand of how much the structure is influenced by the tectonic history and also by the activity of the NAF. Recent studies have claimed that the crustal thickness varies significantly on the north and south of the NAF, which is assumed to indicate the separation line between Eurasian and Anatolian Plates. The present study aims to reevaluate the claim above, using newly available data and recently developed tools. The methods used during the study are the receiver function analysis and surface wave analysis. The first one is more intensively applied, since the second one only serves to introduce stability constraint in the inversions. Data are obtained from the permanent network of KOERI and from PIRES arrays.  The main result of the study indicates that the receiver functions for the stations close to the fault zone are essentially very different from the rest and should be treated separately. They show signs of complex 3D structures of which two were successfully analyzed by forward modeling (HRTX and ADVT). A dipping shallow layer is seen to satisfy the major part of the azimuthal variation at these two stations. For the stations off the fault on the other hand, the receiver functions show a more stable behavior and are analyzed successfully by classical methods. CCP stacking, H-k estimation, single and joint inversion with surface waves, are used for that purpose. The results obtained from these totally independent approaches are remarkably consistent with each other. It is observed that the crustal thickness does not vary significantly neither in the NS, nor in the SW direction. A deeper Moho can only be expected on two most NE stations where a gradual transition is more likely than a sharp boundary (SILT and KLYT). The structural trends, although not significant, are generally aligned in the EW direction.  In particular, a slower lower crust is observed in the southern stations, which is possibly linked to the mantle upwelling and thermal transient of the Aegean extension. Otherwise neither the velocity, nor the thickness of the crust does not imply any significant variation across the fault zone, as was previously claimed.</p>

scholarly journals Crustal structure of southeast Australia from teleseismic receiver functions

Solid Earth ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 463-481
Author(s):  
Mohammed Bello ◽  
David G. Cornwell ◽  
Nicholas Rawlinson ◽  
Anya M. Reading ◽  
Othaniel K. Likkason
Keyword(s):  
Crustal Structure ◽  
Seismic Velocity ◽  
Receiver Function ◽  
Crustal Thickness ◽  
Receiver Functions ◽  
Teleseismic Tomography ◽  
Intraplate Volcanism ◽  
Southeast Australia ◽  
Eastern Australia ◽  
Moho Depths

Abstract. In an effort to improve our understanding of the seismic character of the crust beneath southeast Australia and how it relates to the tectonic evolution of the region, we analyse teleseismic earthquakes recorded by 24 temporary and 8 permanent broadband stations using the receiver function method. Due to the proximity of the temporary stations to Bass Strait, only 13 of these stations yielded usable receiver functions, whereas seven permanent stations produced receiver functions for subsequent analysis. Crustal thickness, bulk seismic velocity properties, and internal crustal structure of the southern Tasmanides – an assemblage of Palaeozoic accretionary orogens that occupy eastern Australia – are constrained by H–κ stacking and receiver function inversion, which point to the following: a ∼ 39.0 km thick crust; an intermediate–high Vp/Vs ratio (∼ 1.70–1.76), relative to ak135; and a broad (> 10 km) crust–mantle transition beneath the Lachlan Fold Belt. These results are interpreted to represent magmatic underplating of mafic materials at the base of the crust. a complex crustal structure beneath VanDieland, a putative Precambrian continental fragment embedded in the southernmost Tasmanides, that features strong variability in the crustal thickness (23–37 km) and Vp/Vs ratio (1.65–193), the latter of which likely represents compositional variability and the presence of melt. The complex origins of VanDieland, which comprises multiple continental ribbons, coupled with recent failed rifting and intraplate volcanism, likely contributes to these observations. stations located in the East Tasmania Terrane and eastern Bass Strait (ETT + EB) collectively indicate a crust of uniform thickness (31–32 km), which clearly distinguishes it from VanDieland to the west. Moho depths are also compared with the continent-wide AusMoho model in southeast Australia and are shown to be largely consistent, except in regions where AusMoho has few constraints (e.g. Flinders Island). A joint interpretation of the new results with ambient noise, teleseismic tomography, and teleseismic shear wave splitting anisotropy helps provide new insight into the way that the crust has been shaped by recent events, including failed rifting during the break-up of Australia and Antarctica and recent intraplate volcanism.

scholarly journals Southern Chile crustal structure from teleseismic receiver functions: Responses to ridge subduction and terrane assembly of Patagonia

Geosphere ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 378-391 ◽  
Author(s):  
E.E. Rodriguez ◽  
R.M. Russo
Keyword(s):  
Crustal Structure ◽  
Triple Junction ◽  
Oceanic Lithosphere ◽  
Receiver Functions ◽  
Moho Depth ◽  
The South ◽  
Ridge Subduction ◽  
The North ◽  
Tectonic Processes ◽  
Chile Triple Junction

Abstract Continental crustal structure is the product of those processes that operate typically during a long tectonic history. For the Patagonia composite terrane, these tectonic processes include its early Paleozoic accretion to the South America portion of Gondwana, Triassic rifting of Gondwana, and overriding of Pacific Basin oceanic lithosphere since the Mesozoic. To assess the crustal structure and glean insight into how these tectonic processes affected Patagonia, we combined data from two temporary seismic networks situated inboard of the Chile triple junction, with a combined total of 80 broadband seismic stations. Events suitable for analysis yielded 995 teleseismic receiver functions. We estimated crustal thicknesses using two methods, the H-k stacking method and common conversion point stacking. Crustal thicknesses vary between 30 and 55 km. The South American Moho lies at 28–35 km depth in forearc regions that have experienced ridge subduction, in contrast to crustal thicknesses ranging from 34 to 55 km beneath regions north of the Chile triple junction. Inboard, the prevailing Moho depth of ∼35 km shallows to ∼30 km along an E-W trend between 46.5°S and 47°S; we relate this structure to Paleozoic thrust emplacement of the Proterozoic Deseado Massif terrane above the thicker crust of the North Patagonian/Somún Cura terrane along a major south-dipping fault.

Dipping structure under Dourbes, Belgium, determined by receiver function modeling and inversion

1995 ◽  
Vol 85 (1) ◽  
pp. 254-268 ◽  
Author(s):  
Jie Zhang ◽  
Charles A. Langston
Keyword(s):  
Receiver Function ◽  
Receiver Functions ◽  
P Wave ◽  
P Waves ◽  
S Waves ◽  
The North ◽  
Shear Wave Velocities ◽  
Geophysical Surveys ◽  
Vector Rotation ◽  
Anomalous Particle

Abstract Teleseismic broadband P and S waves recorded at the NARS station NE06 (Dourbes, Belgium) are shown to exhibit strong anomalous particle motion not attributable to instrument miscalibration or malfunction. Azimuthally varying radial and tangential components have been observed on 38 recordings after vector rotation of horizontal P waves into the ray direction. The tangenital P waves attain amplitudes comparable to the radial components from the east with negative polarity and west with positive polarity, but tend to be zero in the north and south, suggesting major discontinuities in the crust dipping southward. The SH wave from the east contains a large SPmP phase, an S-to-P conversion at the free surface and then reflected back to the surface from the Moho. The polarity of this SPmP phase presents further evidence for a southward-dipping Moho. We employ ray theory for three-dimensionally dipping interfaces to compute the P-wave response. Linear inverse theory with smoothness constraints is applied to the simultaneous inversions of P-wave receiver functions for four different backazimuths. Through the progressive change of interface strike and dip and the inversion of layer shear-wave velocities, a dipping crustal model that is consistent with both the observed waveforms and results of previous local geophysical surveys has been determined. The results suggest a large velocity contrast in the shallow structure near the surface, another major interface at a depth of 12 km with dip of 10°, and a seismically transparent unit below the interface. The interface at a depth of 12 km reportedly emerges at the Midi fault 50 km north of the station NE06.

Deep deformation process of the NE Tibetan Plateau: evidence from receiver function imaging

2020 ◽  
Author(s):  
yifang chen ◽  
jiuhui chen
Keyword(s):  
Tibetan Plateau ◽  
Seismic Velocity ◽  
Receiver Function ◽  
Decisive Role ◽  
Deformation Mode ◽  
Receiver Functions ◽  
Tibet Plateau ◽  
The Tibetan Plateau ◽  
Waveform Data ◽  
The North

<p>The deformation of Qilian Orogenic Belt, which is the uplifting front of the northeastern Tibet Plateau, plays a decisive role in understanding the dynamic process of the area uplift. Many of the tectonic processes models of the Tibetan Plateau growth, which are based on geophysical and geological studies, have been conducted in recent years. However, the deformation mode of northeastern Tibetan Plateau (NETP) remains controversial for lack of sufficient proofs. We used teleseismic waveform data collected from the China Array seismic experiment during 2013-2015 and QL temporary stations during 2016-2017. In this study, we used the 3-D Common Conversion Point (CCP) technique (with the P/S receiver functions) to obtain detailed seismic velocity discontinuities structure of lithosphere beneath the NETP and Alxa block. Our preliminary results can be summarized as follows: 1) The Lithosphere asthenosphere boundary (LAB) lies at a depth pf 110-140 km in Alxa platform, deepens below the North Qilian mountain (160-170 km ) which has been inserted by lithosphere of Central Qilian, between the South Qilian suture zone (SQL) and the north of the Songpan-Ganzi Terranes (160-170 km). 2) The main features in the crust include offset of Moho beneath NQLF, shallower crust thickness below between the NQLF and LSSF and a continuous positive interface over the Moho in the north of the LSSF. 3) According to our observation and previous studies, we suppose that lithosphere had been passive underthrust and localized crust had been shortened and thickened in the NETP.</p>

Imaging the Moho and Main Himalayan Thrust beneath the Kumaon Himalaya: constraints from receiver function analysis

2020 ◽  
Vol 224 (2) ◽  
pp. 858-870
Author(s):  
Devajit Hazarika ◽  
Somak Hajra ◽  
Abhishek Kundu ◽  
Meena Bankhwal ◽  
Naresh Kumar ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Receiver Function ◽  
Function Analysis ◽  
Crustal Thickness ◽  
Receiver Functions ◽  
P Wave ◽  
Poisson's Ratio ◽  
Kumaon Himalaya ◽  
Receiver Function Analysis ◽  
Lower Crustal

SUMMARY We analyse P-wave receiver functions across the Kumaon Himalaya and adjoining area to constrain crustal thickness, intracrustal structures and seismic velocity characteristics to address the role of the underlying structure on seismogenesis and geodynamic evolution of the region. The three-component waveforms of teleseismic earthquakes recorded by a seismological network consisting of 18 broad-band seismological stations have been used for receiver function analysis. The common conversion point (CCP) depth migrated receiver function image and shear wave velocity models obtained through inversion show a variation of crustal thickness from ∼38 km in the Indo-Gangetic Plain to ∼42 km near the Vaikrita Thrust. A ramp (∼20°) structure on the Main Himalayan Thrust (MHT) is revealed beneath the Chiplakot Crystalline Belt (CCB) that facilitates the exhumation of the CCB. The geometry of the MHT observed from the receiver function image is consistent with the geometry revealed by a geological balanced cross-section. A cluster of seismicity at shallow to mid-crustal depths is detected near the MHT ramp. The spatial and depth distribution of seismicity pattern beneath the CCB and presence of steep dipping imbricate faults inferred from focal mechanism solutions suggest a Lesser Himalayan Duplex structure in the CCB above the MHT ramp. The study reveals a low-velocity zone (LVZ) with a high Poisson's ratio (σ ∼0.28–0.30) at lower crustal depth beneath the CCB. The high value of Poisson's ratio in the lower crust suggests the presence of fluid/partial melt. The shear heating in the ductile regime and/or decompression and cooling associated with the exhumation of the CCB plausibly created favorable conditions for partial melting in the lower crustal LVZ.

Crustal structure of the hawaiian ridge near gardner pinnacles

1960 ◽  
Vol 50 (4) ◽  
pp. 563-573
Author(s):  
George G. Shor
Keyword(s):  
Crustal Structure ◽  
Seismic Refraction ◽  
Pacific Basin ◽  
The North ◽  
North Side ◽  
The Pacific ◽  
Oceanic Sediments ◽  
Hawaiian Ridge ◽  
Volcanic Islands ◽  
Mohorovičić Discontinuity

ABSTRACT A series of seismic refraction profiles has been made across a flat bank at Gardner Pinnacles (a pair of volcanic islets on the western Hawaiian Ridge) down the side of the ridge and across the adjacent deep to the floor of the Pacific basin. The ridge is composed principally of material with velocities typical of volcanic islands. The high-velocity oceanic crust, found in the oceanic areas adjacent, extends beneath the ridge and up into the center of the rise. The total crustal section is thickened and the Mohorovičić discontinuity depressed beneath the deep as well as beneath the ridge. The smooth “archipelagic apron” on the north side of the ridge has at most 20 meters of sediment over a layer with a velocity of 3 km/sec, which could be volcanic and is definitely of higher velocity than normal oceanic sediments.

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