Insight Into Frontal Seismogenic Zone in the Mentawai Locked Region From Seismic Full Waveform Inversion of Ultralong Offset Streamer Data

Qin, Yanfang; Singh, S. C.

doi:10.1029/2018gc007787

Cited by 19 publications

(17 citation statements)

References 120 publications

(166 reference statements)

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“…We define a time window centred at the seafloor reflection. We identify this phase by using a maximum kurtosis and k statistics criterion (Saragiotis et al, 2002). We calculate the travel time of the seafloor reflection approximately using a water velocity of 1.5 km s −1 , the seafloor depth, and the source-receiver offset distance.…”

Section: Full-waveform Inversion Resultsmentioning

confidence: 99%

Full-waveform inversion of short-offset, band-limited seismic data in the Alboran Basin (SE Iberia)

et al. 2019

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Abstract. We present a high-resolution P-wave velocity model of the sedimentary cover and the uppermost basement to ∼3 km depth obtained by full-waveform inversion of multichannel seismic data acquired with a 6 km long streamer in the Alboran Sea (SE Iberia). The inherent non-linearity of the method, especially for short-offset, band-limited seismic data as this one, is circumvented by applying a data processing or modelling sequence consisting of three steps: (1) data re-datuming by back-propagation of the recorded seismograms to the seafloor; (2) joint refraction and reflection travel-time tomography combining the original and the re-datumed shot gathers; and (3) full-waveform inversion of the original shot gathers using the model obtained by travel-time tomography as initial reference. The final velocity model shows a number of geological structures that cannot be identified in the travel-time tomography models or easily interpreted from seismic reflection images alone. A sharp strong velocity contrast accurately defines the geometry of the top of the basement. Several low-velocity zones that may correspond to the abrupt velocity change across steeply dipping normal faults are observed at the flanks of the basin. A 200–300 m thick, high-velocity layer embedded within lower-velocity sediment may correspond to evaporites deposited during the Messinian crisis. The results confirm that the combination of data re-datuming and joint refraction and reflection travel-time inversion provides reference models that are accurate enough to apply full-waveform inversion to relatively short offset streamer data in deep-water settings starting at a field-data standard low-frequency content of 6 Hz.

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Section: Full-waveform Inversion Resultsmentioning

confidence: 99%

Full-waveform inversion of short-offset, band-limited seismic data in the Alboran Basin (SE Iberia)

et al. 2019

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“…While some studies use waveform-modeling in downward continued data (Qin and Singh, 2018), here only the travel time information is used for inversion. The wavefield during the back-propagation is altered due to several factors.…”

Section: Discussionmentioning

confidence: 99%

“…A common approach to mitigate the above-mentioned issues and apply TTT+FWI to marine MCS data in deep water settings is by re-datuming the collected data to a virtual recording surface first (e.g., Qin and Singh, 2017)), so that refracted waves can be identified as first arrivals in the virtual recordings and TTT can be conducted. Then first arrival TTT is applied, and the resulting model is used as a reference for multi-scale FWI starting at the lowest available frequency (e.g., Qin and Singh, 2018).…”

mentioning

confidence: 99%

Full waveform inversion of short-offset, band-limited seismic data inthe Alboran basin (SE Iberia)

Gras¹,

Sallarès²,

Dagnino³

et al. 2019

Preprint

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Abstract. We present a high-resolution P-wave velocity model of the sedimentary cover and the uppermost basement until ~ 3 km depth obtained by full-waveform inversion of multichannel seismic data acquired with a 6 km-long streamer in the Alboran Sea (SE Iberia). The inherent non-linearity of the method, especially for short-offset, band-limited seismic data as this one, is circumvented by applying a data processing/modeling sequence consisting of three steps: (1) data re-datuming by back-propagation of the recorded seismograms to the seafloor; (2) joint refraction and reflection travel-time tomography combining the original and the re-datumed shot gathers; and (3) FWI of the original shot gathers using the model obtained by travel-time tomography as initial reference. The final velocity model shows a number of geological structures that cannot be identified in the travel-time tomography models or easily interpreted from seismic reflection images alone. A sharp strong velocity contrast accurately defines the geometry of the top of the basement. Several low-velocity zones that may correspond to the abrupt velocity change across steeply dipping normal faults are observed at the flanks of the basin. A 200–300 m thick, high-velocity layer embedded within lower velocity sediment may correspond to evaporites deposited during the Messinian crisis. The results confirm that the combination of data re-datuming and joint refraction and reflection travel-time inversion provides reference models that are accurate enough to apply full-waveform inversion to relatively short offset streamer data in deep water settings starting at field-data standard low frequency content of 6 Hz.

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“…The OBH geometry places the shots and receivers on a different datum. To relocate the shots and have them at approximately the same datum level as the receivers, we applied a wave equation datuming 33,34,63,64 to a constant depth, which is the shallowest point of the seafloor depth along a profile. Finally, to compensate for the small elevation differences between sources and receivers, we applied static corrections.…”

Section: Methodsmentioning

confidence: 99%

Discovery of flat seismic reflections in the mantle beneath the young Juan de Fuca Plate

et al. 2020

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Crustal properties of young oceanic lithosphere have been examined extensively, but the nature of the mantle lithosphere underneath remains elusive. Using a novel wide-angle seismic imaging technique, here we show the presence of two sub-horizontal reflections at ∼11 and ∼14.5 km below the seafloor over the 0.51-2.67 Ma old Juan de Fuca Plate. We find that the observed reflectors originate from 300-600-m-thick layers, with an ∼7-8% drop in P-wave velocity. They could be explained either by the presence of partially molten sills or frozen gabbroic sills. If partially molten, the shallower sill would define the base of a thin lithosphere with the constant thickness (11 km), requiring the presence of a mantle thermal anomaly extending up to 2.67 Ma. In contrast, if these reflections were frozen melt sills, they would imply the presence of thick young oceanic lithosphere (20-25 km), and extremely heterogeneous upper mantle.

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Insight Into Frontal Seismogenic Zone in the Mentawai Locked Region From Seismic Full Waveform Inversion of Ultralong Offset Streamer Data

Cited by 19 publications

References 120 publications

Full-waveform inversion of short-offset, band-limited seismic data in the Alboran Basin (SE Iberia)

Full-waveform inversion of short-offset, band-limited seismic data in the Alboran Basin (SE Iberia)

Full waveform inversion of short-offset, band-limited seismic data inthe Alboran basin (SE Iberia)

Discovery of flat seismic reflections in the mantle beneath the young Juan de Fuca Plate

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