日本地球惑星科学連合2016年大会

講演情報

インターナショナルセッション(口頭発表)

セッション記号 M (領域外・複数領域) » M-TT 計測技術・研究手法

[M-TT05] Cryoseismology - a new proxy for detecting surface environmental variations of the Earth -

2016年5月26日(木) 10:45 〜 12:15 202 (2F)

コンビーナ:*金尾 政紀(国立極地研究所)、坪井 誠司(海洋研究開発機構)、伊藤 武男(名古屋大学大学院環境学研究科附属 地震火山研究センター)、Wiens Douglas(Washington University in St Louis)、Anandakrishnan Sridhar(Penn State University)、Winberry Jeremy(Central Washington University)、Anderson Kent(Incorporated Research Institutions for Seismology)、座長:豊国 源知(東北大学 大学院理学研究科 地震・噴火予知研究観測センター)、伊藤 武男(名古屋大学大学院環境学研究科附属 地震火山研究センター)

11:15 〜 11:45

[MTT05-02] Repeating Glacial Earthquakes Reveal Migration of Subglacial Sticky-spots.

★招待講演

*Jeremy Paul Winberry1Audrey D Huerta1Howard Conway2Sridhar Anandakrishnan4Richard Aster3Michelle Koutnik2Andrew Nyblade4Douglas Wiens5 (1.Central Washington University、2.University of Washington、3.Colorado State University、4.Pennsylvania State University、5.Washington University in Saint Louis)

キーワード:ice sheet, repeating earthquake, glacier

Many glaciers primarily dissipate their gravitational potential energy by sliding along the ice-bedrock interface. In such cases, a glacier’s driving stress is often balanced by regions of enhanced basal traction known as sticky-spots. While the role of sticky-spots in the force budget of glaciers and ice streams has long been recognized, their formation remains less well understood. In this presentation, we leverage recent advances in seismograph coverage in the Transantarctic Mountains (TAM) to study relatively large glacial seismic events (> M2) that can be observed at regional distances. We report on 5 newly discovered and one previously studied sequences of repeating glacial earthquakes. These new sequences reveal that families can remain active for up to 7 years. Additionally, by tracking subtle changes in relative arrival times as well as waveform similarity, we deduce that these sticky-spots originate from migrating bands of basal debris.