Deep magma underpressure and connectivity drives large dike intrusions
Data files
May 28, 2026 version files 1.36 GB
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InSAR.zip
429.52 MB
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model.zip
119.53 KB
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README.md
5.07 KB
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seismic.zip
5.85 KB
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suppl.zip
932.22 MB
Abstract
Large dikes are the main mechanism of crustal extension in volcanic areas, but the processes in the underlying magma system that supply the required volumes remain unclear. We show that 1.4 km3 of magma propagated under the Ethiopian rift in December 2024 and continued for ~3-months. Geodesy and seismicity reveal that the dike was fed from a network of magma reservoirs between ~56-12 km depth with pathways rapidly forming between them. We calculate pressure changes in the reservoirs and show that underpressure developed in the deeper portion, creating the conditions to drain large magma volumes. We find that tectonic stress and availability of magma alone are not enough to drive intrusion of massive dikes. Such events will start only after magma connectivity and deep underpressure develop. Similar conditions may be important for the transfer of large magma volumes from the mantle and the formation of Large Igneous Provinces (LIP).
Dataset DOI: 10.5061/dryad.7d7wm389h
Description of the data and file structure
The folders InSAR.zip, model.zip and seismic.zip contain the data and material shown in the main paper. The folder suppl.zip contains the data and materials shown in the Supplementary Materials
seismic.zip
The folder seismic contains the seismicity file seismic.txt. The table has ten columns with date, time, lat(deg), lon(deg), depth(km), hsigma(km), zsigma(km),mw, mwrange and cluster, where hsigma is the horizontal uncertainty, zsigma is the vertical uncertainty, mw is the moment magnitude, mwrange is the error bar of the moment magnitude, and cluster is the seismicity group from cluster analysis
InSAR.zip
The folder InSAR contains the wrapped interferograms shown in Fig. 1. The files are in GMT .grd format and geocoded in the EPSG:4326 reference system. File names convention is as follows: orb_reference(yymmdd)_secondary(yymmdd).grd. GMT (The Generic Mapping Tools) software can be used to view/work with the .grd files, and it is freely available here https://www.generic-mapping-tools.org
model.zip
The folder model contains several files: the files idis_bvlsX.csv, volumesX.out and tot_op_sl
- files named idis_bvlsX.csv contain the modeled distributed dike opening for each time interval. The files report informations for each dike patch. Coordinates and depth refer to the top-back vertex, with strike following the right hand rule. Columns are organized as follows: #No = patch number; lon(d) = longitude in decimal degrees; lat(d) = latitude in decimal degrees; D(km) = depth in km; L(km) = Length in km; W(km) = Width in km; str(d) = Strike in degrees w.r.t. North; dip(d) = dip angle; op(mm) = Opening in mm.
- The folder model also contains files named volumesX.out with the sills' and dike's volumes in km^3, and the volume ratios for each time interval. Columns are organized as follows:
- VS1(km^3) = volume of shallower sill
- VS2(km^3) = volume of deeper sill
- VD1(km^3) = volume of southern dike segment
- VD2(km^3) = volume of intermediate dike segment
- VD3(km^3) = volume of northern dike segment
- TotS(km^3) = total sills' volume
- TotD(km^3) = total dikes' volume
- VR= volume ratio
- tot_op_sl.csv contains the cumulative distributed faults slip, dikes opening and sills contraction during the whole dike intrusion. The file is organized as follows:
- lines starting with >-Z report longidute (degrees), latitude (degrees), depth (km), strike-slip in mm (ss), dip-slip in mm (ds) and opening in mm (op). Coordinates and depth are reffered to the patch's centroid. Positive strike-slip values indicate left-lateral component while negative values indicate right-lateral slip. Negative dip-slip values indidicate normal faulting. Negative opening values indicate contraction
- Each >-Z line is followed by 4 triplets of longitude, latitude and depth that define the tree-dimentional patch orientation and can be used for plotting. The patches of faults that activated beyond Dofen can be found starting from line 7222
suppl.zip
The folder suppl contains:
- i) nine subfolders with the InSAR observations and models for nine different time intervals. These files have names starting with suffixes 1-9 followed by the primary date (yymmdd) and the secondary date (yymmdd) of the interferograms and the figure numbers where they are shown in the paper. Each of these nine subfolders contain the models, as binary .dat files (there are as many .dat files as modelled interferograms), and the corresponding interferograms, as matlab files .mat in the folder /input. Each .mat file contains the interferogram and its header file. There is also a .csv file that contains the distributed model for each patch of the dislocations as follows: the flags ">-Z" followed by longitude, latitude, depth, strike-slip in mm (ss_mm), dip-slip in mm (ds_mm), opening in mm (op_mm) and (sp_mm). The .mat files can be opened with the software Matlab (Mathworks) for which free trials are available here https://it.mathworks.com/campaigns/products/trials.html. The .dat files can be opened with Matlab or GMT
- ii) the subfolder deep_collapse_figS22BE contains two forward models of the caldera collapse, as binary .dat files
- iii) the subfolder faulting_figS13 contains the models of the fault NE of Dofen and SW of Dofen in two separate folders, continuing the same file structure described in i)
- iv) the subfolders named figureS17-19 contain forward models whose input interferograms are in the subfolder named /input and the models are in the subfolders S*
- v) the subfolders named post_intrusion_inflation_figS20 contain the models of the post intrusion uplift at Fentale for two interferograms, the .dat files named model*.dat. The input interferograms are in the subfolder named /input
