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    A new family of spherical harmonic geomagnetic field models spanning the past 9000 yr based on magnetic field directions and intensity stored in archaeological artefacts, igneous rocks and sediment records. The pfm9k geomagnetic field models and datafiles as well as the individual bootstraps of the pfm9k.1b geomagnetic field model presented in A. Nilsson, R. Holme, M. Korte, N. Suttie and M. Hill (2014): Reconstructing Holocene geomagnetic field variation: new methods, models and implications. Geophys. J. Int., doi: 10.1093/gji/ggu120 are included here.

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    Text files of physical parameters controlled or measured in rock heating and deformation experiments; jpg and tif files of optical and electron microscope images of experimental products; xome xlsx spreadsheets related to data interpretation.

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    All the raw experimental data obtained for the study reported in Hodgson, E., Grappone, J. M., Biggin, A. J., Hill, M. J., & Dekkers, M. J. (2018). Thermoremanent behavior in synthetic samples containing natural oxyexsolved titanomagnetite. Geochemistry, Geophysics, Geosystems, 19. https://doi.org/10.1029/2017GC007354

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    P* data obtained through hydrostatic loading experiments, using triaxial experimental apparatus, as well as yield curve data obtained through differential loading tests, prior to the discovery of P* for different synthetic sandstones. The methodology used was taken from Bedford et al. (2018, 2019). Grain size analysis data obtained using a Beckman Coulter LS 13 320 laser diffraction particle size analyser. Particle analysis was conducted on five different synthetic sandstones with different grain size distributions. Secondary electron and backscatter electron SEM images for natural and synthetic sandstones. Secondary electron images were stitched together to form a whole core image. They were then binarised following the methodology of Rabbani and Ayatollahi. (2015). Hexagon grid size data used to obtain the correct grid size for performing porosity analysis across an mage using Fiji software (Brown, 2000). Bedford, J. D., Faulkner, D. R., Leclère, H., & Wheeler, J. (2018). High-Resolution Mapping of Yield Curve Shape and Evolution for Porous Rock: The Effect of Inelastic Compaction on 476 Porous Bassanite. Journal of Geophysical Research: Solid Earth, 123(2), 1217–1234. Bedford, J. D., Faulkner, D. R., Wheeler, J., & Leclère, H. (2019). High-resolution mapping of yield curve shape and evolution for high porosity sandstone. Journal of Geophysical Research: Solid Earth. Brown, G. O., Hsieh, H. T., & Lucero, D. A. (2000). Evaluation of laboratory dolomite core sample size using representative elementary volume concepts. Water Resources Research, 36(5), 484 1199–1207. Rabbani, A., & Ayatollahi, S. (2015). Comparing three image processing algorithms to estimate the grain-size distribution of porous rocks from binary 2D images and sensitivity analysis of the grain overlapping degree. Special Topics & Reviews in Porous Media: An International Journal, 6(1).

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    Data files have .dat extension and can be opened with Notepad or any basic text editor software. Each file contains details of sample name, dimensions (length and diameter). All deformed samples were pre-prepared cylinders of synthetic neighbourite. Each file contains 11 data column as follows: Time (hours); Time (secs); CP (V); Vol (V); Force(V); Temp (V); Disp(V); Euro disp (mm); Furn T (mV); PoreP (mV); Furnace Power where V= Volts, mV= millivolts. The Calibration sheet (specific to the apparatus used) uploaded together with the data files is required to convert V and mV raw data into values of stress, strain, strain rate, confining pressure and temperature.

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    Seismic waveforms from an explosion catalogue from a seismic network at Santiaguito volcano between November 2014 and December 2018. A network of 6 broadband and 6 short-period stations was used to record explosive volcanic activity. Waveforms from 18,895 explosions have been automatically been detected and extracted.

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    The data are from a suite of friction experiments performed on 3 different grain size quartz gouges (5, 15 and 30 microns). The quartz gouge layers were sheared under a range of effective normal stresses (40-120 MPa), at a displacement rate of 1 micron/s, and the evolution of shear stress was monitored with increasing displacement (up to a maximum displacement of 8.5 mm). The gouges typically exhibit a transition from stable sliding, where the gouge layers shear in a continuous smooth fashion, to unstable sliding with displacement, where the gouges exhibit stick-slip behaviour. The transition from stable to unstable sliding occurs more efficiently in fine-grained quartz gouges and is promoted by high effective normal stresses.

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    This dataset is the output of a NERC fellowship aimed to understand the long-term dynamics of tropical vegetation through palaeoecological analysis. For doing this, two sedimentary archives (Laguna Pindo and Laguna Baños) from Ecuador were radiocarbon dated and analysed for pollen, non-pollen palynomorphs, charcoal, chironomids, stable isotopes and XRF of tephra deposits. Each proxy was analysed at different resolution. Laguna Pindo is a mid-elevation lake (1250 m asl) that spans the last 50,000 years. Laguna Baños is an Andean lake located at 3800 m asl and contains sediments representative of the last 6500 years. Both water bodies are very shallow. The data is presented mainly in excel spreadsheets as raw data (except for radiocarbon dating data, which are the PDF files provided by NRCF and are available in the NGDC), without any math treatment or conversion (unless specified). NERC fellowship is NE/J 018562/1.

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    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.

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    This dataset contains data from two seismic and one infrasound array deployed at Mt. Etna during the late part of the 2020-2021 eruptive crises (May-November 2021). The arrays were composed as follow: 1) a 7-element array of 3-component, broadband (Trillium T120 compact) seismometers; 2) a 5-element array of 3-component short-period (Lennartz LE-3Dlite-MkII); 3) a 6-element array of broadband infrasound microphones (IST2018). All data were recorded with a sampling rate of 100 Hz and 24-bit resolution using Digos Datacube3 digitizers. The data were collected through a collaboration between the University of Liverpool, UK, and the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Italy, with the purpose of characterizing pre- and syn-eruption tremor signals at Etna, and their links to the timing, style and intensity of paroxysmal eruptive activity at the volcano. The dataset contains records of different examples of paroxysmal activity (i.e., intense episodes of sustained Strombolian explosions accompanied by emission of ash at the vent) as well signals associated with as explosive degassing at the summit vent. Data recovery rates for this experiment were high; there are only very minor gaps in the data owing to periods of scheduled maintenance and data download during the deployment period.