Resources

GMT is a great tool for plotting focal mechanisms, but it doesn't give much flexibility to explore the data especially when you're still in the exploration stage of your work and needing to zoom in and zoom out all a certain region. Here I compiled some python codes and instructions to plot focal mechanisms on QGIS and Google Earth.

There are a few steps to plot focal mechanisms data into QGIS and Google Earth. First, we have to make sure the data is in the correct format (column order). Next, we generate the SVG file (vector data) for EACH focal mechanisms. Finally, we load the focal mechanisms data stored in KML (Google Earth) file (or point XY data would do too) into QGIS and link it with the SVG files. It might sounds very tedious, but the results would be very handy especially in the exploratory stage of earthquake and tectonics spatial analysis.

This code is a compilation from various sources that I tried to make it as easy as possible. I lost track on the original source of the code. If you believe that you created the original code, please let me know so I can put the appropriate citation or references.

I applied Hough Transform principle to identify any potential alignments in a distributed point set data. This method has been used in earth sciences to detect aligned structures, including volcanic vents and monogenetic volcanoes. The quality of data fit to each potential great circle was quantified by rms-misfit. I applied this method to detect lineaments in arc volcano distributions (e.g., Mariana, Java, Sumatra, and more arcs in a global scale study). This method can be applied for other point set data, such as earthquake distributions. Please refer to this paper for the detailed explanation on Hough Transform principle.

Here I put the Matlab code and an example dataset (XLSX).

If you use or modify this code, please cite this paper appropriately when you publish your work.