GPS/Acoustic seafloor geodetic observation: method of data analysis and its application

摘要: We have been developing a system for detecting seafloor crustal movement by combining kinematic GPS and acoustic ranging techniques. A linear inversion method is adopted to determine the position of stations from coordinates moving survey vessel measured travel times waves in seawater. The positioning accuracy substantially improved estimating temporal variation velocity structure. apply our data acquired at reference point, MYGI, located off Miyagi Prefecture, northeast Japan, where huge earthquake expected occur near future. time series horizontal MYGI obtained seven campaign observations period 2002–2005 exhibits trend with scattering rms about 2 cm. fit gives an intraplate more than several centimeters per year towards WNW, which implies strong interplate coupling around this region. precision each solution was examined other points along Nankai Trough through comparison independent one-day subset solutions within campaign. resultant repeatability looks be well-correlated spatial stability structure seawater depending on region as well season.