Surface level measurements of the Erebus volcano lava lake, Antarctica. Surface level was measured from a site at the crater rim using the Eredar radar system, a ground-based X-band FMCW radar (described in detail here: https://doi.org/10.1029/2018GL079177). The dataset contains a single continuous measurement period from 2016 (all times in UTC): 19 Dec 00:35 -> 19 Dec 19:21 Measurements were taken at a rate of ~0.25 Hz, using a 0.16 s 400 MHz bandwidth Linear Frequency Modulated chirp centred at 10.4 GHz, with 10 chirps being averaged for each measurement.

Surface level measurements of the Halema'uma'u lava lake, Hawaii. Surface level was measured from a site at the crater rim (19.40452 N 155.27944 W 1125 M a.s.l) using the Eredar radar system, a ground-based X-band FMCW radar (described in detail here: https://doi.org/10.1029/2018GL079177). Due to technical problems, the radar did not acquire continuously throughout its deployment. The dataset contains three blocks of successful continuous measurement periods (all times in UTC): 10 Jan 22:18 -> 11 Jan 08:46 11 Jan 21:24 -> 12 Jan 22:49 14 Jan 20:27 -> 14 Jan 23:01 Measurements were taken at a rate of ~1 Hz, using a 20 ms 400 MHz bandwidth Linear Frequency Modulated chirp centred at 10.25 GHz.

Thermal and Alternating Field demagnetisation data from Carboniferous-age rock material from Cumbria and the Scottish Borders sampled in 2017. This data is divided into multiple four letter coded sections which refer to a specific locality and/or experiment type. BORD are alternating field demagnetisation results on volcanic material from the Scottish Borders, 330 million years old, sampled in the summer of 2017, carried out by Dr Courtney Sprain. BORR are thermal demagnetisation results on volcanic material from Burnmouth Harbour, Longhoughton Beach, Pease Bay, Joppa Shore, Sugar Sands Bay and Ross Beach in the Scottish Borders, 330 million years old, sampled in the summer of 2017, carried out by Dr Courtney Sprain. CMBR are thermal demagnetisation results on rock material from around Cumbria, 330 million years old, and sampled in Spring 2017, sampled and carried out by Dr Courtney Sprain and Dr Mark Hounslow. CUMB are alternating field demagnetisation results on rock material from around Cumbria, 330 million years old, and sampled in spring 2017, sampled and carried out by Dr Courtney Sprain and Dr Mark Hounslow.

The files contain backscattered (BSE) SEM images and photomicrographs of studied samples form Vanua Lava, Vanuatu (New Hebrides). The samples are mantle xenolith found in situ in lava boulders.

Major and trace element data for partial melts derived from high pressure-temperature experiments on a basaltic starting composition from the Ontong Java Oceanic Plateau.

Primary data, model initial conditions, model results, a compiled database of olivine diffusivity experiments and supplementary tables used in the paper: 'Mutch, E. J. F., Maclennan J., Shorttle, O., Edmonds, M. & Rudge, J. F., (2019), Rapid trans-crustal magma movement under Iceland, Nature Geoscience'. Data_S1 contains electron probe microanalysis (EPMA) profile data of olivine crystals used in this study. This file also includes all of the initial conditions for forsterite content (XFo), Ni and Mn used in the diffusion modelling. Standard deviations are averaged values of standard deviations from counting statistics and repeat measurements of secondary standards. Data_S2 is a compiled database of olivine diffusion experiments used to derive multiple linear regressions for diffusion coefficients and associated covariance matrices. Regressions were only made through [001] data. Data_S3 contains median values for all of the inverted parameters estimated for each crystal profile from the Nested Sampling Bayesian inversion for each type of initial condition and model equation. All of the Monte Carlo realisations for each model are also included in this file. Table_S1 is a supplementary table that contains olivine diffusion equation regression parameters derived and used as part of this study. Table_S2 is a supplementary table that contains covariance matrices for olivine diffusion equations derived in this study. Table_S3 is a supplementary table that contains covariance matrices for aSiO2 (silica activity) dependent olivine diffusion equations derived in this study. Table_S4 is a supplementary table that contains angles between the EPMA profile and the main crystallographic axes in olivine as measured by EBSD. These angles are incorporated into the anisotropy calculation used to determine the apparent diffusivity parallel to the measured profile. angle100P, angle010P and angle001P are the angles between the profile and [100], [010] and [001] respectively. Table_S5 is a supplementary table that contains ,median timescales and 1 sigma errors obtained from the posterior distributions of the Nested Sampling Bayesian inversion conducted on each olivine profile. The results using Al-based initial conditions, constant initial conditions (diffusion only), and aSiO2 based equations using Al-based initial conditions are presented here. The classification of each profile (growth-dominated vs. Al-decoupled) is also shown. See paper (Mutch, E. J. F., Maclennan J., Shorttle, O., Edmonds, M. & Rudge, J. F., (2019), Rapid trans-crustal magma movement under Iceland, Nature Geoscience) for more details.