The thermal state of marine sediments controls a range of potential dehydration reactions as sediments are subducted. In thick sediment sections it is possible that reactions that would normally occur within a subduction zone start offshore of the deformation front. This scenario may be occurring at the Sumatra subduction zone (e.g. Geersen et al., 2013; Huepers et al., 2017). We have investigated this possibility by modelling the thermal and depth history of sediments offshore Sumatra. We have used a range of different assumptions about how the sediments decompact with depth, as well as testing the dependence on the seismic velocities used for depth conversion of the horizons.

Groundwater level measurements collected by the state groundwater boards of Punjab and Haryana states, India, and by the Central Groundwater Board. The data consist of well locations and measurements of groundwater levels, in metres below the top of the well casing. Data were collected in both the pre-monsoon (May-June) and post-monsoon (October-November) periods. Data availability is irregular across the entire suite of wells.