[MIS24-P07] Detection of seafloor crustal deformation from ocean bottom pressure data after applying amplitude corrections on non-tidal components in Hikurangi subduction margin
To reduce the non-tidal component on observed data, we minimize differences between observed and modeled non-tidal components on OBPG data using amplitude correction factor. The observed and modeled components show high correlation with no phase difference, whereas their amplitudes are not completely consistent with each other; the amplitude of the modeled component is generally smaller than that of the observed one in the target area. After removing tidal components and instrumental drift with BAYTAP08 (Tamura et al., 2008), we calculate a correction factor that is a scaling factor of observed/modeled amplitudes of non-tidal components by minimizing the total residual between observed and corrected model amplitude. After multiplying the correction factor to the modeled one, we remove it from the observed OBPG data to reduce the non-tidal variations more effectively than previous works. As the results, variances of time series of OBP record after removal of tide and non-tidal components decreased ~ 30% at most. It is expected that detection ability of tectonic movement is improved by taking pressure differences from the record at a reference site, which is also processed by the same procedure.