下記のとおり地震研究所談話会を開催いたします。

ご登録いただいたアドレスへ、開催当日午前中にURL・PWDをお送りいたします。
なお、お知らせするzoomURLの二次配布はご遠慮ください。また、著作権の問題が
ありますので、配信される映像・音声の録画、録音を固く禁じます。

　記

　　　　日　　時：　令和4年9月16日(金)　午後１時３０分～　
　　　　開催方法：　インターネット　WEB会議

1. 13:30-13:45
   演題：Classification of Low Frequency Earthquakes at Mount Fuji
   著者：○Adele DOUCET (IPGP/ERI：インターンシップ研修生)・Yosuke AOKI、Nobuaki FUJI (IPGP)
   要旨：We show the first approach of classification of Low frequency earthquakes at Mount Fuji.
2. 13:45-14:00
   演題：三陸沖海底光ケーブルを用いた音響分散型センシングによる地震観測【2021年度所長裁量経費報告】
   著者：○篠原雅尚・山田知朗・悪原 岳・望月公廣・酒井慎一
3. 14:00-14:15
   演題：地震研さくらサイエンス2022の活動概要
   著者：○木下正高・照原陽子・山田祐子・杉崎伊利也・福井 萌

○発表者
※時間は質問時間を含みます。
※既に継続参加をお申し出いただいてる方は、当日zoomURLを自動送信いたします。
※談話会のお知らせが不要な方は下記までご連絡ください。

〒113－0032　東京都文京区弥生1－1－1　
東京大学地震研究所 共同利用担当
E-mail：k-kyodoriyo(at)eri.u-tokyo.ac.jp

※次回の談話会は令和4年10月21日(金)　午後１時３０分～です。

Title: Seismo-acoustic observations of the remarkable atmospheric waves from the January 2022 Hunga, Tonga volcanic eruption

Abstract:  The 15 January 2022 volcanic eruption of Hunga, Tonga produced atmospheric waves that stunned both scientists and the general public. These waves were observed globally by a multitude of instruments and technologies. The most notable atmospheric wave was an acoustic-gravity “Lamb” wave that was detected globally on barometers, infrasound sensors, seismometers, and satellites. This Lamb wave propagated across the globe numerous times and contributed to fast-arriving, hazardous tsunamis that were not forecasted. The Hunga Lamb wave resembled the Lamb wave produced by the 1883 Krakatau eruption, but was observed by a much denser instrument network. Notably, infrasound waves also propagated around the globe numerous times, and audible acoustic waves were heard out to an unprecedented 9000 km. Current wave propagation models do not sufficiently explain these observations. Here I present some notable observations of the atmospheric waves from the Hunga eruption, many of them detailed in a recent highly collaborative manuscript. I focus on the Lamb, infrasound, and acoustic wave observations, including some surprising observations made near the source as well as across the dense geophysical network in Alaska. The atmospheric waves from this eruption provide a landmark dataset for scientists to study for many years.

概要
1923年関東地震から100年の節目を迎えるにあたり、東京大学本郷で得られた観測記録・歴史資料・津波堆積物等の研究において、新たな資料の発掘や再発見が報告されている。本研究集会では、これらを俯瞰した議論を行い、1923年関東地震とその発生履歴の総合的理解を目的とする。

本研究集会は、東京大学地震研究所共同利用(2022-W-09)の援助をうけています。

日時
2022年8月31日（水）9時10分〜15時15分（予定）

場所（開催方法）
オンライン会議（Zoomを利用）

参加方法・詳細はこちらから：https://www.eri.u-tokyo.ac.jp/people/ykano/kanto100/

Title: Beyond Life-Safety: The Quest Continues

Abstract:

Current versions of seismic design codes worldwide aim to achieve life-safety in severe and rare earthquakes. As a result, not many modern buildings have collapsed, and people have rarely died in such buildings even in severe earthquakes. However, current seismic design principles allow structures to be damaged even in minor-moderate shakings. Consequently, modern building stocks have suffered damage in all recent earthquakes, and the financial losses to the community arising from damage and downtime of these buildings have been unacceptably high in many earthquakes.

Following the 2010-11 Canterbury (New Zealand) earthquake sequence, New Zealand engineers (justifiably) claimed that the performance of building stock in general was better than what they were designed to achieve. This has perplexed the New Zealand public who are still struggling to cope with the huge scale of financial loss caused by this earthquake sequence. Hence, it is necessary that the seismic design objectives be revised to meet public expectations.

Observations from recent earthquakes have highlighted that the majority of seismic loss in buildings are attributable to damage of secondary components (known as non-structural elements; i.e. NSEs). Hence, enhancing seismic performance of non-structural elements (SPONSE) is a must if we want to minimize financial implications of future earthquakes. Unsurprisingly, awareness of the importance of SPONSE research has significantly increased lately, and researchers are striving to better understand the inherent weaknesses in the current NSEs’ design and installation practices and to develop low-damage solutions for key NSEs.