Vertical movements of Earth's surface and the rocks that lie beneath it occur around many parts of the globe in response both to tectonic and non-tectonic processes (e.g. glacial unloading, igneous intrusion). Upward vertical movement (uplift) forms topography, which generally results in erosion; and downward vertical movement (subsidence) creates accommodation space, which generally results in burial. In return, particularly over long timescales, feedbacks occur such that erosion and burial may enhance uplift and subsidence, respectively. Thus, it is vitally important to understand the fundamental drivers of uplift and subsidence (e.g. tectonic or non-tectonic) and the relationship with erosion and burial.
For nuclear facilities, the impacts of uplift and erosion generally are more significant than the impacts of subsidence and burial (McKinley and Chapman, Chapter 24, this volume). Furthermore, given the rates of vertical movement (typically < 10mma−1) and the timescales of interest for different kinds of nuclear facilities, their impacts are most significant for geological repositories for long-lived radioactive waste. The potential impacts of uplift, subsidence, erosion and burial on geological repositories are described in McKinley and Chapman (Chapter 24, this volume) and McKinley and Alexander (Chapter 22, this volume). Briefly, the key factors of interest are: (i) the average regional rate of uplift or subsidence (on a scale on the order of tens or hundreds of kilometers); (ii) the magnitude of differential uplift and erosion (on a scale of 100m to several kilometers); (iii) the potential for extreme, localized erosion or burial; and (iv) the balance between uplift and erosion, and subsidence and burial.