Onshore/Offshore Structure of the Juan de Fuca Plate in Northern Cascadia from Bayesian Receiver Function Inversion

Brillon, Camille; Cassidy, John F.; Dosso, Stan E.

doi:10.1785/0120120310

Cited by 9 publications

(6 citation statements)

References 29 publications

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“…The seismological characteristics of incoming oceanic plates in various subduction zones have been investigated by both active and passive seismic surveys (e.g., Ranero et al 2003;Ranero and Sallarès 2004;Grevemeyer et al 2007;Shinohara et al 2008;Brillon et al 2013;Fujie et al 2013Fujie et al , 2016Obana et al , 2013Obana et al , 2014Obana et al , 2018Kodaira et al 2014;Bécel et al 2015;Shillington et al 2015). Several active survey results have revealed seismic velocity reductions at the uppermost oceanic plate near trenches (Ranero et al 2003;Ranero and Sallarès 2004;Grevemeyer et al 2007;Fujie et al 2013;Shillington et al 2015), which can be explained by fractures associated with plate bending in the outer-rise region (Faccenda et al 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Although most passive seafloor observations use teleseismic waves because part or all survey areas are distant from seismically active regions (e.g., Brillon et al 2013), the high-frequency components of such waves are insufficient relative to those of active sources. If converted waves could be retrieved from passive seismic surveys at high frequencies, signals obtained from different approaches could be compared or interpreted.…”

Section: Introductionmentioning

confidence: 99%

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Lateral variation of the uppermost oceanic plate in the outer-rise region of the Northwest Pacific Ocean inferred from Po-to-s converted waves

Tonegawa

Obana

Fujie

et al. 2018

Earth Planets Space

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The uppermost structures of incoming oceanic plates have been investigated by seismic exploration surveys, primarily based on two-dimensional profiles. However, their regional-scale lateral variations and shear wave velocity structures with higher-frequency components remain elusive. This study, using passive seismic records, attempted to retrieve Po-to-s converted waves (Pos) by cross-correlating Po wave coda from the radial and vertical components in the 2-6 Hz frequency band and to show lateral variations of the shear wave velocity within the oceanic crust, including crust-related seismic interfaces and layer-dependent anisotropic structures. Po waves were collected from continuous records acquired from active seismic surveys performed across wide areas of the Northwestern Pacific over shorter observation periods and passive seismic surveys performed near the Japan Trench over longer observation periods. As a result, this study obtained clear Pos waves converted at the basement and oceanic Moho of the seaward region, whereas weakened or no Pos waves were observed at ocean bottom seismometers near the trench. The primary reasons for Pos wave weakening or absence were considered to be structural changes, including normal faults due to the plate flexures in the outer-rise region, hydration at the uppermost oceanic plate, and fractures associated with volcanic activities that can be seen on the oceanic plate (petit spots). Furthermore, layer-dependent shear wave anisotropies were estimated for the sediment and crust. Fast polarization directions were oriented in trench-parallel directions near the trench and in the NNW-SSE directions in the seaward region. The pattern change to near-trench polarization directions would correspond to stress field-induced aligned fractures, including cracks and normal faults, created by stress fields induced by plate bending in the outer-rise region.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lateral variation of the uppermost oceanic plate in the outer-rise region of the Northwest Pacific Ocean inferred from Po-to-s converted waves

Tonegawa

Obana

Fujie

et al. 2018

Earth Planets Space

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“…However, there are mulReceiver functions using OBS data 3 tiple complications related to receiver functions using OBS data and in fact very few studies have reported unambiguous results (e.g. Niu et al, 2007;Ball et al, 2014;Brillon et al, 2013;Reeves et al, 2015;Janiszewski & Abers, 2015). Such complications are mainly associated with ocean wave-related noise sources and the reverberating effects of the overlying water column and thin marine sedimentary layers.…”

Section: Introductionmentioning

confidence: 99%

Receiver functions using OBS data: promises and limitations from numerical modelling and examples from the Cascadia Initiative

Audet¹

2016

Geophys. J. Int.

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SUMMARYThe expanding fleet of broadband ocean-bottom seismograph (OBS) stations is facilitating the study of the structure and seismicity of oceanic plates at regional scales. For continental studies, an important tool to characterize continental crust and mantle structure is the analysis of teleseismic P receiver functions. In the oceans, however, receiver functions potentially suffer from several limiting factors that are unique to ocean sites and plate structures. In this study we model receiver functions for a variety of oceanic lithospheric structures to investigate the possibilities and limitations of receiver functions using OBS data. Several potentially contaminating effects are examined, including pressure reverberations from the water column for various ocean-floor depths and the effects of a layer of low-velocity marine sediments. These modelling results indicate that receiver functions from OBS data are difficult to interpret in the presence of marine sediments, but shallow-water sites in subduction zone forearcs may be suitable for constraining various crustal elements around the locked megathrust fault. We propose using a complementary approach based on transfer function modelling combined with a grid search approach that bypasses receiver functions altogether and estimates model properties directly from minimally processed waveforms. Using real data examples from the Cascadia Initiative, we show how receiver and transfer functions can be used to infer seismic properties of the oceanic plate in both shallow (Cascadia forearc) and deep (Juan de Fuca Ridge) ocean settings.

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“…However, existing RF images only sample the plate boundary deeper than the locked zone because past broadband arrays are on land. Brillon et al (2013) analyze RFs from two ocean-bottom seismometers (OBSs) offshore of Vancouver Island, but poor data quality at these stations contributes to large uncertainties.…”

Section: Introductionmentioning

confidence: 99%

Imaging the Plate Interface in the Cascadia Seismogenic Zone: New Constraints from Offshore Receiver Functions

Janiszewski

Abers

2015

Seismological Research Letters

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Onshore/Offshore Structure of the Juan de Fuca Plate in Northern Cascadia from Bayesian Receiver Function Inversion

Cited by 9 publications

References 29 publications

Lateral variation of the uppermost oceanic plate in the outer-rise region of the Northwest Pacific Ocean inferred from Po-to-s converted waves

Lateral variation of the uppermost oceanic plate in the outer-rise region of the Northwest Pacific Ocean inferred from Po-to-s converted waves

Receiver functions using OBS data: promises and limitations from numerical modelling and examples from the Cascadia Initiative

Imaging the Plate Interface in the Cascadia Seismogenic Zone: New Constraints from Offshore Receiver Functions

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