megaquake
In the latest research, Yo Fukushima, associate professor at Tohoku University's International Research Institute of Disaster Science, and other scientists calculated the probability of successive Nankai Trough earthquakes by elapsed time since the initial tremor, based on the cases of successive megaquakes recorded in international earthquake statistics and the history of past Nankai Trough earthquakes since 1361 where the certainty of occurrence was high.
these sentences are a part of an original article.
because of saving usage of comma this whole original article is flowingly readable/comprehensible.
回答
in the the Japanese translation of these sentences the part ' based on the cases of successive megaquakes recorded in international earthquake statistics and the history of past Nankai Trough earthquakes since 1361 where the certainty of occurrence was high.' are cut from main sentences separately.
one punctuation changing could connect this phrase with the main sentence. try to change punctuation under the help of GT.(from comma to semi-colon)
:Probability of ensuing megaquake after Nankai Trough tremor high.
https://mainichi.jp/english/articles/20230111/p2a/00m/0sc/015000c
:GT.
https://translate.google.co.jp/?hl=ja&sl=en&tl=ja&op=translate