A regular study meeting was held to evaluate the possibility of a large earthquake in the Nankai Trough, and the opinion that "no particular changes have been observed" was summarized.
A study group made up of experts analyzed the data observed in and around the hypocenter area of the Nankai Trough.
Small-scale earthquakes called "deep low-frequency earthquakes" occurred in and around the hypocenter area
from January 14 to 2 in the Tokai region, and from January
2 to 11 in the central and western parts of the Kii Peninsula.
▽ It was also observed in western Shikoku from the 8th to the 10th of last month.
Along with this, slight crustal movements were observed by multiple "strain meters" in the surrounding area.
These are thought to be caused by "short-term slow slip" that slowly shifts at the deep boundary of the plate in the hypocenter area.
All of these are phenomena that are frequently observed in and around the hypocenter area, and the study group said, "A special change that is thought to have increased the possibility of a large-scale earthquake relative to normal times has been observed. I haven't done it. "
Before 11 years after the Great East Japan Earthquake, Naoshi Hirata, the chairman of the study group and a counselor of the National Research Institute for Earth Science and Disaster Prevention, said, "Over time, awareness of the earthquake may diminish not only in Tohoku but also outside Tohoku. However, even in the Nankai Trough, the Philippine Sea plate is steadily subducting into the plate on the land side, and it is almost certain that this strain will be eliminated. The huge earthquake that occurred in eastern Japan 11 years ago was in western Japan. But please be aware that it is likely to happen and be prepared. "