Changes in Greenland ice bed conditions inferred from seismology

Genti Toyokuni, Hiroshi Takenaka, Ryota Takagi, Masaki Kanao, Seiji Tsuboi, Yoko Tono, Dean Childs, Dapeng Zhao

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Basal conditions of the Greenland Ice Sheet (GrIS) are a key research topic in climate change studies. The recent construction of a seismic network has provided a new opportunity for direct, real-time, and continuous monitoring of the GrIS. Here we use ambient noise surface wave data from seismic stations all over Greenland for a 4.5-year period to detect changes in Rayleigh-wave phase velocity between seismic station pairs. We observe clear seasonal and long-term velocity changes for many pairs, and propose a plausible mechanism for these changes. Dominant factors driving the velocity changes might be seasonal and long-term pressurization/depressurization of the GrIS and shallow bedrock by air and ice mass loading/unloading. However, heterogeneity of the GrIS basal conditions might impose strong regionalities on the results. An interesting feature is that, even at adjacent two station pairs in the inland GrIS, one pair shows velocity decrease while another shows velocity increase as a response to the high air and snow pressure. The former pair might be located on a thawed bed that decreases velocity by increased meltwater due to pressure melting, whereas the latter pair might be located on a frozen bed that increases velocity by compaction of ice and shallow bedrock. The results suggest that surface waves are very sensitive to the GrIS basal conditions, and further observations will contribute to a more direct and quantitative estimation of water balance in the Arctic region.

Original languageEnglish
Pages (from-to)81-98
Number of pages18
JournalPhysics of the Earth and Planetary Interiors
Volume277
DOIs
Publication statusPublished - Apr 1 2018

Fingerprint

seismology
Greenland
ice sheet
beds
ice
surface wave
stations
bedrock
surface waves
ambient noise
Arctic regions
phase velocity
air
Rayleigh wave
unloading
water balance
meltwater
wave velocity
water budget
air masses

Keywords

  • Changes in Rayleigh-wave phase velocity
  • Greenland Ice Sheet (GrIS)
  • Ice sheet basal conditions
  • Pressure melting
  • Seismic interferometry

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Geophysics
  • Physics and Astronomy (miscellaneous)
  • Space and Planetary Science

Cite this

Changes in Greenland ice bed conditions inferred from seismology. / Toyokuni, Genti; Takenaka, Hiroshi; Takagi, Ryota; Kanao, Masaki; Tsuboi, Seiji; Tono, Yoko; Childs, Dean; Zhao, Dapeng.

In: Physics of the Earth and Planetary Interiors, Vol. 277, 01.04.2018, p. 81-98.

Research output: Contribution to journalArticle

Toyokuni, Genti ; Takenaka, Hiroshi ; Takagi, Ryota ; Kanao, Masaki ; Tsuboi, Seiji ; Tono, Yoko ; Childs, Dean ; Zhao, Dapeng. / Changes in Greenland ice bed conditions inferred from seismology. In: Physics of the Earth and Planetary Interiors. 2018 ; Vol. 277. pp. 81-98.
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