Probability of Magnitude 7 Earthquake Directly Under Tokyo Within Next 4 Years is 70%, According to Tokyo University Study

Probability of Magnitude 7 Earthquake Directly Under Tokyo Within Next 4 Years is 70%, According to Tokyo University Study
Yomiuri Shimbun: M7級首都直下地震、4年内70%…東大地震研
January 23, 2012

The probability of a Magnitude 7 earthquake directly under Tokyo within the next four years is 70%, according to calculations by the Tokyo University Earthquake Research Team.

The Great Tōhoku Earthquake awakened tectonic activity beneath the metropolis, the group noted. In comparison to the government’s earthquake research commission’s evaluation that an earthquake in Southern Kantō, the area which includes the capital, within the next 30 years was 70%, this prediction is much more worrying.

The capital has been a much more active earthquake zone since the Great Tōhoku Earthquake last March 11. According to the Weather Bureau, from that date to the end of December, there were 1.48 Magnitude 3-6 earthquakes per day in greater Tokyo, a rate about 5 times higher than the earthquake frequency before that date.

Tokyo University team member Dr. Naoshi Hirata and company are keeping an eye on this activity. The team based their calculation on the empirical rule that an earthquake of a given magnitude is one tenth as frequent as an earthquake one order of magnitude weaker and ten times more frequent than an earthquake one order of magnitude stronger.

M7級首都直下地震、4年内70%…東大地震研

 マグニチュード(M)7級の首都直下地震が今後4年以内に約70%の確率で発生するという試算を、東京大学地震研究所の研究チームがまとめた。

 東日本大震災によって首都圏で地震活動が活発になっている状況を踏まえて算出した。首都直下を含む南関東の地震の発生確率を「30年以内に70%程度」としている政府の地震調査研究推進本部の評価に比べ、切迫性の高い予測だ。

 昨年3月11日の東日本大震災をきっかけに、首都圏では地震活動が活発化。気象庁の観測によると12月までにM3~6の地震が平均で1日当たり1・48回発生しており、震災前の約5倍に上っている。

 同研究所の平田直(なおし)教授らは、この地震活動に着目。マグニチュードが1上がるごとに、地震の発生頻度が10分の1になるという地震学の経験則を活用し、今後起こりうるM7の発生確率を計算した。

(2012年1月23日03時04分 読売新聞)

Explore posts in the same categories: Japan, Science, Math, Technology, Translations

Tags:

You can comment below, or link to this permanent URL from your own site.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


%d bloggers like this: