Automated Detection, Extraction, and Measurement of Regional Surface Waves

Levshin, A. L.; Ritzwoller, M. H.

doi:10.1007/978-3-0348-8264-4_11

Cited by 111 publications

(95 citation statements)

References 15 publications

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“…Next, we applied frequency-time analysis (Levshin and Ritzwoller, 2001) to the selected seismograms to verify the quality of the group-velocity spectrum and to identify the most reliable period range with robust dispersion measurements. Finally, we measured interstation phase velocity dispersion using a cross-correlation method (Bao et al, 2011(Bao et al, , 2014Yao et al, 2005Yao et al, , 2006.…”

Section: Inter-station Phase-velocity Measurements From Teleseismic Rmentioning

confidence: 99%

Large variations in lithospheric thickness of western Laurentia: Tectonic inheritance or collisional reworking?

Bao

Eaton

2015

Precambrian Research

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Section: Inter-station Phase-velocity Measurements From Teleseismic Rmentioning

confidence: 99%

Large variations in lithospheric thickness of western Laurentia: Tectonic inheritance or collisional reworking?

Bao

Eaton

2015

Precambrian Research

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“…We also include unpublished ambient noise measurements from the NGRI (National Geophysical Research Institute) Uttaranchal network and from published ambient noise measurements on the south Indian Shield (Borah et al 2014). The dispersion from the earthquake seismograms was determined manually; the dispersion from the ambient noise Green's functions was determined automatically (Levshin & Ritzwoller 2001).…”

Section: Data a N D A N A Ly S I Smentioning

confidence: 99%

Lateral variations in the crustal structure of the Indo–Eurasian collision zone

Gilligan

2018

Geophysical Journal International

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S U M M A R YThe processes involved in continental collisions remain contested, yet knowledge of these processes is crucial to improving our understanding of how some of the most dramatic features on the Earth have formed. As the largest and highest orogenic plateau on the Earth today, Tibet is an excellent natural laboratory for investigating collisional processes. To understand the development of the Tibetan Plateau, we need to understand the crustal structure beneath both Tibet and the Indian Plate. Building on previous work, we measure new group velocity dispersion curves using data from regional earthquakes (4424 paths) and ambient noise data (5696 paths), and use these to obtain new fundamental mode Rayleigh wave group velocity maps for periods from 5 to 70 s for a region including Tibet, Pakistan and India. The dense path coverage at the shortest periods, due to the inclusion of ambient noise measurements, allows features of up to 100 km scale to be resolved in some areas of the collision zone, providing one of the highest resolution models of the crust and uppermost mantle across this region. We invert the Rayleigh wave group velocity maps for shear wave velocity structure to 120 km depth and construct a 3-D velocity model for the crust and uppermost mantle of the Indo-Eurasian collision zone. We use this 3-D model to map the lateral variations in the crust and in the nature of the crust-mantle transition (Moho) across the Indo-Eurasian collision zone. The Moho occurs at lower shear velocities below northeastern Tibet than it does beneath western and southern Tibet and below India. The east-west difference across Tibet is particularly apparent in the elevated velocities observed west of 84• E at depths exceeding 90 km. This suggests that Indian lithosphere underlies the whole of the Plateau in the west, but possibly not in the east. At depths of 20-40 km our crustal model shows the existence of a pervasive mid-crustal low velocity layer (∼10% decrease in velocity, V s < 3.4 km s −1 ) throughout all of Tibet, as well as beneath the Pamirs, but not below India. The thickness of this layer, the lowest velocity in the layer and the degree of velocity reduction vary across the region. Combining our Rayleigh wave observations with previously published Love wave dispersion measurements, we find that the low velocity layer has a radial anisotropic signature with V sh > V sv . The characteristics of the low velocity layer are supportive of deformation occurring through ductile flow in the mid-crust.

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“…Group velocities were determined using frequency-time analysis (FTAN, e.g. Levshin et al 1992) and a phase-matched filtering approach (Levshin & Ritzwoller 2001;Arroucau et al 2010;Young et al 2011) on the envelope of the symmetric component (averaged causal and acausal parts) of the empirical Green's functions. Only cross-correlograms between stations with a spatial separation larger than 3 wavelengths were used for the retrieval of dispersion curves (e.g.…”

Section: E T H O Dmentioning

confidence: 99%

Crustal surface wave velocity structure of the east Albany-Fraser Orogen, Western Australia, from ambient noise recordings

Sippl

Tkalčić²,

Gessner

et al. 2017

Geophysical Journal International

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S U M M A R YGroup and phase velocity maps in the period range 2-20 s for the Proterozoic east AlbanyFraser Orogen, Western Australia, are extracted from ambient seismic noise recorded with the 70-station ALFREX array. This 2 yr temporary installation provided detailed coverage across the orogen and the edge of the Neoarchean Yilgarn Craton, a region where no passive seismic studies of this scale have occurred to date. The surface wave velocities are rather high overall (>3 km s −1 nearly everywhere), as expected for exposed Proterozoic basement rocks. No clear signature of the transition between Yilgarn Craton and Albany-Fraser Orogen is observed, but several strong anomalies corresponding to more local geological features were obtained. A prominent, NE-elongated high-velocity anomaly in the northern part of the array is coincident with a Bouguer gravity high caused by the upper crustal metamorphic rocks of the Fraser Zone. This feature disappears towards longer periods, which hints at an exclusively upper crustal origin for this anomaly. Further east, the limestones of the Cenozoic Eucla Basin are clearly imaged as a pronounced low-velocity zone at short periods, but the prevalence of low velocities to periods of ≥5 s implies that the uppermost basement in this area is likewise slow. At longer periods, slightly above-average surface wave velocities are imaged below the Eucla Basin.

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Automated Detection, Extraction, and Measurement of Regional Surface Waves

Cited by 111 publications

References 15 publications

Large variations in lithospheric thickness of western Laurentia: Tectonic inheritance or collisional reworking?

Large variations in lithospheric thickness of western Laurentia: Tectonic inheritance or collisional reworking?

Lateral variations in the crustal structure of the Indo–Eurasian collision zone

Crustal surface wave velocity structure of the east Albany-Fraser Orogen, Western Australia, from ambient noise recordings

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