The 2004 Sumatra, 2010 Maule, and 2011 Tohoku great earthquakes triggered tsunamis as large as a few decimeters over a few 100 km in the open ocean. The transient ocean mass redistribution propagating as tsunamis changed the Earth’s gravity field enough to perturb the GRACE satellites’ orbits at ~ 500 km above the surface. The on-board microwave ranging system detected inter-satellite acceleration anomalies of up to 1.0–4.0 nm/s2. There is good agreement between GRACE measurements and tsunami models for the three events. Complementarily to buoys, ocean bottom pressure sounders, and satellite altimeters, GRACE is sensitive to the long-wavelength spatial scale of tsunamis and provides an independent source of information for assessing alternate early earthquake and tsunami models. Our study demonstrates an innovative way of applying GRACE and GRACE Follow-On data to detect transient geophysical mass changes which cannot be observed by the conventional monthly Level-2 and mascon solutions.

中文翻译：

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2004 年、2010 年和 2011 年大地震后海啸的 GRACE 重力测量

2004 年的苏门答腊、2010 年的马乌莱和 2011 年的东北大地震在公海引发了几分米的海啸。随着海啸传播的瞬态海洋质量重新分布改变了地球的重力场，足以扰乱 GRACE 卫星在地表上方约 500 公里处的轨道。机载微波测距系统检测到高达 1.0–4.0 nm/s2 的卫星间加速度异常。这三个事件的 GRACE 测量值和海啸模型之间有很好的一致性。作为浮标、海底压力测深仪和卫星高度计的补充，GRACE 对海啸的长波长空间尺度敏感，并为评估交替的早期地震和海啸模型提供独立的信息来源。