S-wave Velocity Structure In The Kanto Basin From Frequency-Bessel Transformation Method

Ambient noise exploration is one of the most important method of passive source exploration methods.Ambient noise exploration has been developed rapidly since 21st century because it is easy to acquire data and has no damage to the environment.However,the traditional methods of extracting dispersive curves,which is a vital step of subsurface exploration,are either insensitive to the higher-mode dispersive curves or difficult to extract higher-mode dispersive curves from the ambient noise.The difficulty of extracting higher-mode dispersive curves has been a serious impediment of ambient noise exploration.Luckily,Wang et al.proposed a new method,Frequency-Bessel transformation method(F-J method),to extract dispersive curves.They have proved that the F-J method can extract not only fundamental-mode dispersive curve but also higher-mode dispersive curves by numerical modeling and real data validation.The F-J method gives us a new method to investigate subsurface structure from ambient noise.The Kanto Basin is located in Japan where most earthquakes occur.What' s worst,the thick sedimentary basin in this area can produce very complex wave fields of strong ground motion and the earthquake disaster could be serious because of the large population.As a result,the subsurface structure of the Kanto basin in Japan has been becoming a research hotspot.In addition,there are a lot of seismic stations in the Kanto basin,which supplies vast amounts of data for us.Therefore,it makes sense for us to investigate the subsurface structure of the Kanto Basin.In the paper,we applied the F-J method into the ambient noise data of MeSO-net run by National Institute for Earth Science and Disaster Resilience(NIED)to extract fundamental-mode dispersive curve and higher-mode dispersive curves.Also,Quasi-Newton was used to inversed the S-wave velocity model using dispersive curves and we compared the results with that of JIVSM.As a result,we draw a conclusion that the F-J method is an efficient way to extract higher-mode dispersive curves,which can enhance the constrains on the solutions of the inversion problems.