Instructions on how to install and use SPECFEM2D are available in the PDF manual located in directory doc/USER_MANUAL.
Main "historical" developers: Dimitri Komatitsch and Jeroen Tromp (there are currently many more!)
For a quick test, run the default example with these commands:
./configure FC=gfortran make all ./bin/xmeshfem2D ./bin/xspecfem2D
and check the output files in ./OUTPUT_FILES/