Upper mantle structure beneath the Society hotspot and surrounding region using broadband data from ocean floor and islands

Isse, Takehi; Sugioka, Hiroko; Ito, Aki; Shiobara, Hajime; Reymond, D.; Suetsugu, Daisuke

doi:10.1186/s40623-016-0408-2

Cited by 9 publications

(3 citation statements)

References 23 publications

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“…Tomographic Investigation by seafloor ARray Experiment for the Society hotspot Project (hereinafter TIARES) was designed to image the possible plume with reasonable resolution using both magnetotelluric (MT) and seismological observations [ Suetsugu et al, ; Isse et al, ]. We measured the natural time variations of the magnetic and electric fields in the period range of a few hundred seconds to approximately 1 day to probe the electrical conductivity structure of the upper mantle.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic evidence for volatile‐rich upwelling beneath the society hotspot, French Polynesia

Tada

Tarits

Baba

et al. 2016

Geophysical Research Letters

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We have conducted a seafloor magnetotelluric survey that images, for the first time, three‐dimensional electrical conductivity structure in the upper mantle beneath the Society hotspot. A striking feature in our model is a high‐conductivity anomaly a few hundred kilometers in diameter, which is continuous from the lowest part of the upper mantle to a depth of approximately 50 km below sea level. Using theoretical and experimental results from mineral physics, we interpret the high‐conductivity anomaly as evidence of the melt fraction up to 2.2 vol.%, which is robust regardless of assumed temperature, and the existence of carbonated silicate melt beneath the hotspot. Our results suggest that the Society hotspot is a pathway for ascending volatiles from the deeper part of the upper mantle to the surface.

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Section: Introductionmentioning

confidence: 99%

Electromagnetic evidence for volatile‐rich upwelling beneath the society hotspot, French Polynesia

Tada

Tarits

Baba

et al. 2016

Geophysical Research Letters

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“…The slow anomaly beneath the Society hot spot is related to volcanic activity at the hot spot. The location of the Tuamotu anomaly is close to the slow S velocity anomalies revealed by Rayleigh wave tomography [ Isse et al ., ], indicating that the Tuamotu anomaly is robust. Adam et al .…”

Section: Discussionmentioning

confidence: 99%

Mantle plumes beneath the South Pacific superswell revealed by finite frequency P tomography using regional seafloor and island data

Obayashi

Yoshimitsu

Sugioka

et al. 2016

Geophysical Research Letters

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We present a new tomographic image beneath the South Pacific superswell, using finite frequency P wave travel time tomography with global and regional data. The regional stations include broadband ocean‐bottom seismograph stations. The tomographic image shows slow anomalies of 200‐300 km in diameter beneath most hot spots in the studied region, extending continuously from the shallow upper mantle to 400 km depth. Narrow and weak slow anomalies are detected at depths of 500–1000 km, connecting the upper mantle slow anomalies with large‐scale slow anomalies with lateral dimension of 1000–2000 km prevailing below 1000 km depth down to the core‐mantle boundary. There are two slow anomalies around the Society hot spot at depths shallower than 400 km, which both emerge from the same slow anomaly at 500 km depth. One of them is located beneath the Society hot spot and the other underlies 500 km east of the Society hot spot, where no volcanism is observed.

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“…During this 630-day observation, more than 800 We plan to apply seismic tomography to the data from the OJP array and permanent seismic stations located in the Pacific Ocean to determine three-dimensional seismic velocity structures of the upper mantle beneath the OJP using body wave traveltime tomography (e.g., Obayashi et al, 2016) and surface wave tomography (e.g., Isse et al, 2016) with unprecedented spatial resolution. The lateral and vertical extents of the previously found low-velocity Theoretical traveltime curves predicted by the iasp91 model (Kennett and Engdahl, 1991) are also shown by red lines.…”

Section: Suetsugu Et Almentioning

confidence: 99%

The OJP array: seismological and electromagnetic observation on seafloor and islands in the Ontong Java Plateau

Suetsugu

Shiobara

Sugioka

et al. 2018

JAMSTEC Rep. Res. Dev.

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We conducted geophysical observations on the Ontong Java Plateau (OJP) and its vicinity from late 2014 to early 2017 to determine the underlying crust and upper mantle structure beneath the OJP. Most of the OJP was emplaced in the present South Pacific region at 122 Ma by massive volcanism, but the origin of this volcanism are still debated. Previous studies have suggested that seismic velocity beneath the OJP is anomalously slow, thus this could represent thermal or chemical remnants of the volcanism. However, the seismic resolution of the slow anomalies is poor due to lack of seafloor observations. The observation network named "the OJP array" is composed of seafloor and island stations. The seafloor stations have broadband ocean bottom seismographs and ocean bottom electromagnetometers. The island stations have broadband seismographs. The OJP array is designed to obtain seismic and electrical conductivity structures of the mantle beneath the OJP with better resolution than that of previous studies. Joint analysis and interpretation of seismological and electromagnetic data should provide tight constraints to thermal and chemical structures and clarify the origin of OJP emplacement.

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Upper mantle structure beneath the Society hotspot and surrounding region using broadband data from ocean floor and islands

Cited by 9 publications

References 23 publications

Electromagnetic evidence for volatile‐rich upwelling beneath the society hotspot, French Polynesia

Electromagnetic evidence for volatile‐rich upwelling beneath the society hotspot, French Polynesia

Mantle plumes beneath the South Pacific superswell revealed by finite frequency P tomography using regional seafloor and island data

The OJP array: seismological and electromagnetic observation on seafloor and islands in the Ontong Java Plateau

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