A d3-based velocity analysis tool.

This tool allows one to pick the RMS velocity from a semblance plot (estimate of reflection power as a function of time and velocity) and save the picks to a text file. The semblance and NMO-corrected CDP display are both displayed.

NMO - Normal moveout. The travel time through the velocity model. CDP - Common depth point (also known as CMP or common midpoint) gather.

The semblance calculation and the NMO corrections are done in velServer.py by SU (http://www.cwp.mines.edu/cwpcodes) and provided to d3-velan through websockets.

You must start velServer manually

Download nwjs (http://nwjs.io)

Install node (http://nodejs.org), which includes npm (the node package manager)

Install bower (another package manager(?))

npm install bower -g

git clone https://github.com/sanandak/d3-su-picker
cd d3-su-picker
# install the required packages
bower install
npm install

Install python3 3.5 or less (preferably through anaconda (http://continuum.io))

conda create -n obspy python=3.4 # create a virtual environment
conda activate obspy
conda config --add channels conda-forge
conda install obspy
conda install websockets

Install SU (http://www.cwp.mines.edu/cwpcodes) and make sure $CWPROOT/bin is in the path.

These are installed by npm and bower

• d3js v4
• sprintf-js
• angularjs

These are installed by conda (pip may work - untested)

• obspy
• websockets
• numpy and scipy are installed with obspy

SU

• suvelan: calculates semblance
• sunmo: calculates NMO corrected gather.

cd $HOME/.../d3-velan
python ./velServer.py
/path/to/nwjs .

Buttons to open an SU file and to save velocity picks.

The viewer displays the semblance plot for the first ensemble (by default, the first cdp location). Click on the semblace plot to pick time-velocity pairs to construct a velocity model. The cdp gather is NMO corrected to that model.

The saved picks file is a JSON file that has an array of picks.

• sufile: file name of the picked data
• picktime: when the picking was done
• picks: an array of picks ({t:..., v:..., a:...})

• Read SEG-Y files.
• Read pick files.
• populate pick file more fully