Most tsunamis occur after large submarine earthquakes, particularly in the Pacific Ocean. However, following the 2004 tsunami in the Indian Ocean, tsunami hazard awareness was significantly raised at the global scale, and warning systems were developed in many other regions, where large tsunamis are rarer but can also produce large catastrophes. Here we first review the basic physics of a tsunami, from its triggering to its coastal impact, and we offer a review of the geophysical and sea-level data that can describe the various processes operating during a tsunami. Global Navigation Satellite System (GNSS) data have a key role in better describing the ground deformation following a tsunamigenic earthquake close to the coast. The GNSS observations complement seismological data to constrain the rupture model rapidly and robustly. Interferometric Synthetic Aperture Radar (SAR) also contributes to this field, as well as optical imagery, relevant to monitoring elevation changes following subaerial landslides. The observation of the sea-level variations, in the near field and during the propagation across the ocean, can also increasingly benefit from GNSS data (from GNSS buoys) and from robust satellite communication: pressure gauges anchored on the seafloor in the deep ocean contribute to warning systems only by data continuously transmitted through satellites. The sounding of ionospheric Total Electron Content (TEC) variations through GNSS, altimetry, or a ground-based airglow camera, is a promising way to record tsunami initiation and propagation indirectly. Finally, GNSS, optical and SAR imagery are essential to map and quantify the damage following tsunami flooding. Satellite data are expected to contribute more to operational systems in the future provided they are reliably available and analysed in real time.

中文翻译：

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太空任务对更好的海啸科学的贡献：观测、模型和警告

大多数海啸发生在海底大地震之后，尤其是在太平洋。然而，2004 年印度洋海啸之后，全球范围内的海啸危害意识显着提高，许多其他地区也建立了预警系统，在这些地区，大型海啸较为罕见，但也可能产生大型灾难。在这里，我们首先回顾了海啸的基本物理学，从它的触发到它的沿海影响，我们提供了地球物理和海平面数据的回顾，这些数据可以描述海啸期间运行的各种过程。全球导航卫星系统 (GNSS) 数据在更好地描述靠近海岸的海啸地震后的地面变形方面发挥着关键作用。GNSS 观测与地震数据相辅相成，以快速、稳健地约束破裂模型。干涉合成孔径雷达 (SAR) 以及与监测地面滑坡后的高程变化相关的光学图像也对这一领域有所贡献。在近场和跨洋传播期间对海平面变化的观察也越来越受益于 GNSS 数据（来自 GNSS 浮标）和强大的卫星通信：固定在深海海底的压力计有助于只能通过卫星连续传输的数据向警报系统发送数据。通过 GNSS、高度计或地面气辉相机探测电离层总电子含量 (TEC) 变化是间接记录海啸发生和传播的一种很有前景的方法。最后，GNSS、光学和 SAR 图像对于绘制和量化海啸洪水后的破坏至关重要。