The sequence of earthquakes starting with the Mw 7.2 Sanriku-Oki earthquake on March 9, 2011, and large earthquakes immediately following the Mw 9.0 Tohoku-Chiho Taiheiyo-Oki event are analyzed, and show that there are events that ruptured in regions not covered by the Mw 9.0 earthquake. In the strict definition of foreshocks and aftershocks (earthquake occurring on the rupture plane of the mainshock before and after the mainshock hypocentral time), these earthquakes are not foreshock and aftershocks, but cascading failure of different segments of the plate interface. Almost all of the triggered earthquakes start at the boundary with previous earthquake, and propagate into regions that have not slipped. This observation suggests that the Mw 9.0 earthquake could have been larger (as large as 9.4) if all the segments failed within a single event.
- https://partner.archive-it.org/1131/collections/7472/seeds/2727450
- https://partner.archive-it.org/1131/collections/7472/crawl/1519038
- https://partner.archive-it.org/1131/collections/7472/crawl/1545143/seeds
The sequence of earthquakes starting with the Mw 7.2 Sanriku-Oki earthquake on March 9, 2011, and large earthquakes immediately following the Mw 9.0 Tohoku-Chiho Taiheiyo-Oki event are analyzed, and show that there are events that ruptured in regions not covered by the Mw 9.0 earthquake. In the strict definition of foreshocks and aftershocks (earthquake occurring on the rupture plane of the mainshock before and after the mainshock hypocentral time), these earthquakes are not foreshock and aftershocks, but cascading failure of different segments of the plate interface. Almost all of the triggered earthquakes start at the boundary with previous earthquake, and propagate into regions that have not slipped. This observation suggests that the Mw 9.0 earthquake could have been larger (as large as 9.4) if all the segments failed within a single event.