2:45 PM - 3:00 PM
[SSS10-05] Moment tensor inversion of shallow very low-frequency earthquakes around off the Kii Peninsula, Japan: the effects of three-dimensional accretionary prism model
Keywords:shallow very low-frequency earthquake, accretionary prism, moment tensor inversion, 3D heterogeneous subsurface structure, FDM simulation
We validated our method using the SVLFE catalog by Sugioka et al. (2012). In their work, source parameters were determined by using data from ocean bottom seismometers. Although estimated durations and centroid times were different due to different settings for frequency range and meteorology of moment tensor inversion, our solutions of SVLFEs show low-angle thrust faulting solutions similar to solutions by Sugioka et al. (2012). If we use Green’s functions of the original JIVSM, where the accretionary prism is simply modeled by a single low-velocity layer with VS = 1 km/s, estimated centroid locations and focal mechanisms were not similar to solutions by Sugioka et al. (2012). Our results indicate that the suitable three-dimensional velocity structure model constructed with the amphibious seismic network enables us to obtain accurate moment tensor solutions of offshore earthquakes recorded by land networks.
NIED F-net broadband velocity seismograms were used. SVLFE catalog of Sugioka et al. (2012) was downloaded from the website of slow earthquake database. FDM simulations were conducted on the Earth Simulator at the JAMSTEC.