TephraProb v.1.5

Version releases were never systematically attributed to TephraProb until now. This new version was labeled v1.5 as some important changes have been made.

Changes in TephraProb v1.5

Probability calculations

Changes on storage of probability data have been made to reduce disk space usage and improve speed of reading Tephra2 outputs during probability calculations. Namely, the probability_maker function, accessed from Post processing > Probability calculations in TephraProb, proceeds in 2 steps:

1. Read the Tephra2 output, sums them if needed and stores the output in RunName/RunNb/DATA/dataT2_*.mat. This is a 3D matrix, where the 3rd dimension equals the number of runs (i.e. each summed Tephra2 output is stored along the 3rd dimension). The 1st and 2nd dimensions vary with the grid type:
   • If runs are performed on a full grid, dimensions 1 and 2 are equal to the dimensions of the grid northing and easting, respectively
   • If runs are performed on a list of points, each output is in a 3 column format, with dimension 1 equal to the number of points and dimension 2 being [easting, northing, mass accumulation]
2. This new output is used for probabilit calculations, which are stored in RunName/RunNb/DATA/dataProb.mat. This file loads a Matlab structure containing the outputs of probability maps, probabilistic isomass maps and hazard curves

Note that to save disk space, the output of Tephra2 is now:

1. Rounded to a significant digit number
2. Accumulations below a thresholds are considered equal to zero

Both the significand digit number and the thresholds are controlled in the preferences of TephraProb, accessible from File > Preferences.

Export to ASCII files

ASCII files previously generated upon completion of the post-processing stage are not automatically generated anymore, which save a considerable amount of disk storage (i.e. the 3C/, GIS/ and MAT/ foldeds in the SUM/, PROB/ and IM/ folders). Instead, a new function accessible from Post processing > File management > Export to ASCII files allows the user to choose the type and the format of files to export.

Archive Tephra2 files

A new function available from Post processing > File management > Archive Tephra2 files offers to compress files generated by and for Tephra2 (i.e. the OUT/, CONF/ and GS/ folders). This was also implemented with concern for disk space usage. Note that this function should only be used once the Tephra2 modelling has successfully completed. This process takes a long time due to to the large amount of small files and individual folders created.

Probabilistic isomass maps

The method used to compute probabilistic isomass maps has been re-written and uses a percentile approach rather than an interpolation of iso-probability contours on probability maps. Note that a probability of occurrence of a given isomass is given by the inverse of the percentile, i.e. a percentile of 25% reflects a 75% probability of occurrence.

Hazard curves

It is now possible to import text files in the Input > Points dialogue box. Text files should be 3-columns tab-delimited ASCII files with columns containing:

• Column 1: Point name
• Column 2: Latitude (decimal degree, WGS84)
• Column 3: Longitude (decimal degree, WGS84)

Map preferences

A more in-depth customization of output maps is now offered from File > Preferences. These parameters allow to:

• Scale the colors of probability and isomass maps to the min/max values set in their respective contours. For instance, this is useful for plotting isomass maps for various probability threshold while preserving the value of a pixel color across maps
• Control the display of contours labels. This is useful when the display gets jammed
• Plot the points used for the calculation of hazard curves and their names
• Chose the colormaps
• Plot probabilistic isomass maps with a logarithmic colormap

Bug fix

• A bug was corrected for Plinian scenarios, causing problems in the calculation of eruption duration for eruptions > 6h and the long-lasting option disactivated
• A problem was reported by two users concerning an improper interpretation of ECMWF wind files in Tephra2. The problem is discussed here. Changes were made in TephraProb to avoid the occurrence of this bug, but please check any run that could have been affected