Royal Netherlands Institute for Sea Research

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The Earth’s surface as a water mattress

Large weights displaced on the Earth’s surface, like a mountain slowly moving, a sea disappearing or a glacier retreating, modify the Earth’s gravity field and the elevation of the surface. These variations can affect locations all around the world, even thousands of kilometers away. In this view, the Earth’s surface is more similar to a water mattress than to a solid surface: weights disturb old equilibria and create new ones.

Incorporating sediment into the models

Such processes are so complex that only numerical models called GIA models - from Glacial Isostasy Adjustment - can solve them. Nevertheless, not all the weights can be traced. Usually GIA models take into account only ice-sheets and sea-level variations. I expand these models to incorporate sediment processes.

Weight variations

The faster a weight is displaced, the more abrupt is the surface’s response and the greater our interest in the rebound problem. Mountains’ development, which takes over millions of years, has little influence on our lives. On the other hand, ice sheets variations have effects still visible today, as the current uplift of Norway and Sweden testify. Another process that displaces large weights in a short time window is sedimentation. The whole Netherlands was created by the Rhine’s sediments! In my research, I include sediment processes into GIA models, improving these models and sedimentation models that - so far - do not account for the response of the Earth as a whole.