A Decade of Global Navigation Satellite System/Acoustic Measurements of Back-Arc Spreading in the Southwestern Okinawa Trough

Long-term seafloor geodetic measurements are important for constraining submarine crustal deformation near plate boundaries. Here we present an integrated analysis of a decade GNSS/acoustic data collected at site 60 km to the east northeast Taiwan axis Okinawa Trough back-arc basin. We obtained time-series horizontal and vertical positions based on 18 from 2009 2019. These reveal southeastward movement rate 43 ± 5 mm/yr since 2012 with respect Yangtze Plate. The motion can be explained by clockwise rotation Yonaguni Block northern Central Range. In addition, displacement transponder array shows rapid subsidence 22 9 fast negative free-air gravity anomaly in this region indicate that thinning is compensated mainly surface rather than upward migration Moho. Taking into account offset owing replacement array, position time series our best two linear lines slope change July 2013. timing velocity coincides broadly nearby seismicity dike intrusion 150 away site. Our results highlight potential geodesy assessing temporal changes spreading center Trough, which cannot one using onland GNSS stations.