Seismographic Data Compression-- Applying Modified Tunstall Coding

The Standard for the Exchange of Earthquake Data (SEED) is a commonly used file format in the seismology field. Steim1 and Steim2 compression schemes, i.e. lossless data compressions, are used in SEED format and are written in Data Description Language (DDL), which has computational limitations making it difficult to implement many standard compression algorithms. Steim1 and Steim2 are fixed compression methods, which assign each incoming data sample to fewer bits than 32-bit, regardless of the essence of the data. This project modified the Tunstall compression scheme to gain a better compression ratio of seismic data and rewrote the compressed data in the DDL of SEED format file. This project pre-computed the statistic s on seismic profile bases and,