A regular review meeting was held to assess the possibility of a huge earthquake occurring in the Nankai Trough, and the opinion was summarized that "no particular changes have been observed."
A study group made up of experts analyzed data observed in and around the hypothetical source area of the Nankai Trough.
There has been no noticeable seismic activity since October in the hypothetical focal region of a large earthquake.
On the other hand, in and around the hypothetical focal region
,
small-scale earthquakes called "deep low-frequency earthquakes" occurred. It was
observed
from to October 5, from October
14 to 26 in Tokai, and from
October 16 to 23 in eastern Shikoku .
Along with this, a slight crustal movement was observed with multiple "strain gauges" in the surrounding area, and it is believed that the cause is a "short-term slow slip" that slowly shifts at the deep boundary of the plate in the hypothetical focal region. .
Deep low-frequency earthquakes and short-term slow slips are frequently observed in and around the hypothetical focal region. No particular changes that are thought to have increased have been observed."
Naoshi Hirata, chairman of the study group and professor emeritus at the University of Tokyo, said, "Although no significant earthquakes have occurred in the vicinity of the focal region, preparations are underway for the next earthquake. It is normal that there is a high possibility that an earthquake will occur, so I would like you to continue to prepare so that you will be okay if an earthquake occurs at any time."