Gravity measurements in southeastern Alaska reveal negative gravity rate of change caused by glacial isostatic adjustment

For the past 300 years, southeastern Alaska has undergone rapid ice‐melting and land uplift attributable to global warming. Corresponding crustal deformation (3 cm/yr) caused by the Little Ice Age retreat is detectable with modern geodetic techniques such as GPS and tidal gauge measurements. Geodeti...

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Bibliographic Details
Published in:Journal of Geophysical Research: Solid Earth 2010-12, Vol.115 (B12), p.n/a
Main Authors: Sun, W., Miura, S., Sato, T., Sugano, T., Freymueller, J., Kaufman, M., Larsen, C. F., Cross, R., Inazu, D.
Format: Article
Language:English
Subjects:
Climate change
Geodetics
Geophysical studies
Geophysics
Glaciers
Global positioning systems
Global warming
GPS
gravity change
Ice ages
Ice thickness
Little Ice Age retreat
Melting
postglacial rebound
present-day ice melting
Rock deformation
southeastern Alaska
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Summary:For the past 300 years, southeastern Alaska has undergone rapid ice‐melting and land uplift attributable to global warming. Corresponding crustal deformation (3 cm/yr) caused by the Little Ice Age retreat is detectable with modern geodetic techniques such as GPS and tidal gauge measurements. Geodetic deformation provides useful information for assessing ice‐melting rates, global warming effects, and subcrustal viscosity. Nevertheless, integrated geodetic observations, including gravity measurements, are important. To detect crustal deformation caused by glacial isostatic adjustment and to elucidate the viscosity structure in southeastern Alaska, Japanese and U.S. researchers began a joint 3‐year project in 2006 using GPS, Earth tide, and absolute gravity measurements. A new absolute gravity network was established, comprising five sites around Glacier Bay, near Juneau, Alaska. This paper reports the network's gravity measurements during 2006–2008. The bad ocean model in this area hindered ocean loading correction: Large tidal residuals remain in the observations. Accurate tidal correction necessitated on‐site tidal observation. Results show high observation precision for all five stations:
ISSN:0148-0227
2169-9313
2156-2202
2169-9356
DOI:10.1029/2009JB007194