1. Introduction

The SEISAN seismic analysis system is a complete set of programs and a simple database for analyzing earthquakes from analog and digital data. With SEISAN it is possible using local and global earthquakes to enter phase readings manually or pick them with a cursor, locate events, edit events, determine spectral parameters, seismic moment, azimuth of arrival from 3-component stations and plot epicenters. The system consists of a set of programs tied to the same database. Using the search programs it is possible to use different criteria to search the database for particular events and work with this subset without extracting the events. Most of the programs can operate both in a conventional way (using a single file with many events), or in a database manner. Additionally, SEISAN contains some integrated research type programs like coda Q, synthetic modeling, moment tenesor inversion and a complete system for seismic hazard calculation.

The data is organized in a database like structure using the file system. The smallest basic unit is a file (the S-file) containing original phase readings (arrival times, amplitude, period, azimuth, and apparent velocity) for one event. The name of that file is also the event ID, which is the key to all information about the event in the database. Although the database in reality only consists of a large number of sub-directories and files (all of which the user has access to), the intention is that by using the surrounding software, the user should rarely need to access the files directly, but rather do all work from the user's own directory. Included with SEISAN there is a test data set, a training document using the test data of many events and a tutorial using just the 2 events included with the software. In addtion, there is a document illustrating seismogram analysis using SEISAN. See chapter 5. To get an idea of how SEISAN works, new users can take a look at a SEISAN webinar that was arranged by IRIS in 2014 (see https://www.youtube.com/watch?v=KJH3ktGL_K0 or file seisan_webinar_iris_2014.mov on the SEISAN ftp server).

SEISAN runs under Sun Solaris, Linux, MacOSX and Windows. The programs are mostly written in Fortran, a few in C and almost all source codes is given, so the user should be able to fix bugs and make modifications. The programs have been compiled and linked with system compilers and linkers on SUN, GNU compiler on Linux, Windows and MaxOSX. For graphics, X is used on Unix systems and DISLIN (www.dislin.de) used under Windows. No format conversion is needed to move data files (binary and ASCII) between the systems if one of the standard formats (SEISAN, GSE2.0, SEED, SAC, GURALP) is used. The GUI Seisan Explorer is written in Qt and is used on Linux, MacOSX and Windows.

BE AWARE: A SEISAN S-file must not contain symbols requiring 2 bytes or more (the case with some country letters). The system will crash.

This manual resides in the directory INF (see below), when the system has been implemented on your computer. The file is called seisan.pdf (Adobe PDF).

The SEISAN system is built of programs made by many different individuals without whom it would never have been possible to make SEISAN. Acknowledgement is made throughout this manual where appropriate or in the acknowledgement section at the end. SEISAN now contains so many programs that when a new version is released, it is not possible to check all the options in all programs and we rely on the user to help finding the bugs, please report!

SEISAN is freely available for all non-commercial use.

In this manual names of computer programs are given with capital letters, names of files and command line options are given by typewriter font.