Publication Date:
2019
Description:
〈span〉〈div〉SUMMARY〈/div〉We found that 〈span〉SH〈/span〉〈sub〉diff〈/sub〉 phases generated by earthquakes in the Fiji–Tonga, recorded in India, are accompanied by secondary pulses. We interpreted them as a consequence of multipathing of 〈span〉S〈/span〉 waves caused by the Pacific large low-shear-velocity province (LLSVP). We analysed the differential traveltimes between 〈span〉SH〈/span〉〈sub〉diff〈/sub〉 and the secondary pulse, together with the absolute 〈span〉SH〈/span〉〈sub〉diff〈/sub〉 arrival times, to constrain the thickness and velocity perturbations in the western end of the Pacific LLSVP. Our preferred model shows a lateral variation in the thickness of the LLSVP; the southern part reveals a thicker (300 km) low-velocity region compared to the northern part (200 km). However, the velocity perturbations of the LLSVP appear to be comparable ($-1.5\hbox{ per cent}$). The results are consistent with a scenario that the LLSVP is a chemically distinct pile with significant surface topography.〈/span〉
Print ISSN:
2051-1965
Electronic ISSN:
1365-246X
Topics:
Geosciences
Published by
Oxford University Press
on behalf of
The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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