地球変形の新たなグローバルモード:季節のサイクルが検出されました
G Blewitt1, D Lavallée, P Clarke
1Nevada Bureau of Mines and Geology, and Seismological Laboratory, University of Nevada, Reno, NV 89557, USA. gblewitt@unr.edu
Science (New York, N.Y.)
|December 18, 2001
まとめ
地球 地球 地球 地球 地球 地球
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 固体地球地質物理学 固体地球地質物理学
- ジオデシ (Geodesy) とは
背景:
- 地球の変形は,季節的な質量再分配の影響を受けます.
- 理論的なモデルは,地球全体の変形パターンを予測します.
- グローバル・ポジショニング・システム (GPS) のデータは,正確な地質測定を可能にします.
研究 の 目的:
- 地球変形のグローバルモードを検知し,特徴づけること.
- 表面負荷に対する地球の弾性反応の理論的予測を検証するために.
- 季節的な半球間質量交換を定量化するために.
主な方法:
- グローバル・ポジショニング・システム (GPS) サイトの世界的なネットワークからの正確な位置付けデータを利用しました.
- 2月~3月と8月~9月の変形パターンの季節的変動を分析した.
- 負荷瞬間と質量交換を決定するためにデータ逆転技術を適用した.
主要な成果:
- 理論的な予測と一致する,グローバルで1度目の変形パターンが検出されました.
- 冬の間,北半球の圧縮と南半球の膨張を観測した.
- 北半球の冬にピークに達する量化された有意な半球間質量交換.
結論:
- 検出された変形モードは,季節的な表面質量負荷に対する固体地球の弾性反応を表しています.
- 土壌の水分,雪,大気の季節的な負荷は,地球全体の重要な地球変形を引き起こします.
- この発見は,地球半球間の大規模な周期的な質量再分配を裏付けている.
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