Abstract

The velocity structure and accurate aftershock distributions of the 2004 mid‐Niigata prefecture earthquake are elucidated by inverting the arrival times from 716 aftershocks using double‐difference tomography. Fourteen temporal seismic stations were immediately deployed in and around the source region within 46 h of the occurrence of mainshock. The seismic velocities in a hanging wall are lower than those in a footwall, and the velocity contrast extends to a depth of approximately 10 km. The aftershocks associated with the mainshock are distributed around the clear boundary between the low and high velocity structures. It is interpreted that the mainshock fault plane of the mid‐Niigata prefecture earthquake was reactivated as a reverse fault since the crustal shortening initiated at 3.5 Ma. Crustal stretching or shortening along the Japan coastline has created complex structures such as low velocity zones, which can potentially control the seismic activities around the source region.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.