Broadband seismological observation in Greenland and study of Greenland icequakes

2016 Fiscal Year Final Research Report

• Project/Area Number: 24403006
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 海外学術
• Research Field: Solid earth and planetary physics
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: TSUBOI Seiji 国立研究開発法人海洋研究開発機構, 地球情報基盤センター, 部長 (90183871)
• Co-Investigator(Kenkyū-buntansha): 金尾 政紀 国立極地研究所, 研究教育系, 准教授 (40233845) ; 豊国 源知 東北大学, 理学(系)研究科(研究院), 助教 (90626871) ; 東野 陽子 国立研究開発法人海洋研究開発機構, 地球深部ダイナミクス研究分野, 研究技術専任スタッフ (90359183)
• Project Period (FY): 2012-04-01 – 2017-03-31
• Keywords: 地震 / 極地 / 広帯域地震観測 / グリーンランド氷床 / 氷床地震 / 地殻構造

Outline of Final Research Achievements

We have maintained broadband seismograph station in Greenland to define the fine structure and detailed mechanisms of glacial earthquakes within the Greenland Ice Sheet. We have started to operate ICESG station since 2011. We have visited the station every summer and successfully retrieved one year of continuous records from the broadband seismometer. The observed three component seismograms demonstrate that the quality of this ice sheet station is good enough to record not only local earthquakes around Greeland but also teleseismic earthquakes. We use 4.5-year ambient noise surface wave data from seismic stations all over Greenland to detect both seasonal and long-term changes in seismic velocity beneath the inter-station transect lines. We find a clear summer/long-term velocity decrease beneath a line in the north-central inland of the ice sheet, which is considered as an increase of meltwater due to ice sheet pressure melting.

Free Research Field

固体地球物理学