Abstract
We determined the location, size, mechanism, and the frequency content of the first 4.0 s of the 2011 Tohoku–Oki earthquake. Since the beginning of this earthquake is very small, we develop a comparative approach against a near-by reference earthquake, the master event. We first determined the water depth near the master event using the differential timing between the water phase pwP reflected from the air–water interface and the depth phase pP reflected from the water–crust interface. Then we located the master event using the well-known ocean bathymetry in the area. After calibrating teleseismic arrays (Δ = 30° to 90°) at short periods for timing and amplitude with respect to the master event, we were able to determine the initiation of the main event. It began as a small (M w = 4.9) thrust event located at 38.19°N, 142.68°E at a depth of 21 km, and, a few seconds later, evolved into a slower extremely large slip event up-dip.
Sign-in/Register to access full text options 
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 callDisclaimer: 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.
