Introduction | New User | Analysis | Graphics | Macros | Inline Functions |

Blackboard | Input-Output |Data Format (part 1) | Data Format (part 2) |

Appendix | Application Programmer Interface (API) | API How To

Introduction


Overview

SAC2000 (Seismic Analysis Code for the third millenium) is a general purpose interactive program designed for the study of sequential signals, especially time-series data. Emphasis has been placed on analysis tools used by research seismologists in the detailed study of seismic events. Analysis capabilities include general arithmetic operations, Fourier transforms, three spectral estimation techniques, IIR and FIR filtering, signal stacking, decimation, interpolation, correlation, and seismic phase picking. SAC2000 also contains an extensive graphics capability. Versions are available for a wide variety of computer systems. SAC2000 was developed at Lawrence Livermore National Laboratory and is copyrighted by the University of California.

This Manual

This manual contains general information for the new user about what SAC2000 can do, how it works, and how to get started. It also contains detailed information for the more experienced user on topics such as how to use SAC macros, how to read and write SAC data files from C or FORTRAN programs, and how the SAC2000 program is structured.

Update Policy

This manual will be periodically updated to include new descriptions and to revise old ones. It is suggested that it be kept in a loose leaf binder, to make it easier to incorporate these updates. The pages are not numbered for this reason. Please report any errors in this manual to:

peterg@llnl.gov -- Peter Goldstein
Mail Stop L-205
Lawrence Livermore National Laboratory
Livermore, CA 94550
Email: peterg@llnl.gov

This will help keep it as accurate and current as possible.

Notation

This section describes the notation used in this manual. All of the SAC2000 manuals use a similiar notation.

Uppercase/red words (e.g. READ) identify commands or keywords. They must be entered as shown, although they may be either uppercase or lowercase.

When showing examples of interaction between the user and SAC2000, the user inputs are denoted by ``u:'', and SAC2000's responses by ``s:''. A uppercase typewriter style font is used within these examples, with comments about what is happening appearing in lowercase and enclose in parentheses.

Repeating an important point made above, you may enter keywords and options in either uppercase or lowercase. SAC2000 converts these to uppercase before interpreting them. The exceptions to this rule are text appearing within single or double quotes and the names of directories and files. The case of these items is not changed. They are interpreted literally.

Other Manuals

Other SAC2000 manuals include:

A Tutorial Guide For New Users which explains the basic SAC commands with examples for you to try as you read.

Commands Reference Manual which contains detailed descriptions of each SAC command including purpose, syntax, default values, and examples. This manual also contains lists of SAC commands sorted alphabetically and functionally.

Spectral Estimation Subprocess Manual which describes a subprocess for the study of stationary random processes. A subprocess is like a small separate program within the main SAC2000 program.

Signal Stacking Subprocess Manual which describes a subprocess for performing signal stacking with delays, traveltimes, and record section plots.

SAC Graphics File Users Manual which describes a set of programs that can be used to perform various functions on SAC Graphics Files.

Program Design

Design Philosophy

SAC2000 does not use a channel or a stack design. There are advantages and disadvantages in each of these designs. Concurrent operation was chosen because seismologists tend to perform the same operation on large numbers of seismic signals at the same time. This design sometimes requires you to store intermediate analysis results in temporary scratch files on disk. SAC2000's design was modified in version 10.6e to allow operations on sub-sets of files in memory to help minimize the need for writing temporary disk files.

Version Differences

SAC2000 is a fairly portable code written in C. Two areas that effect portability are operating systems and graphics. There are currently versions for the following different types of computers and UNIX operating systems:

SUN: compiled on Solaris 5.5 and SunOS 4.1.1. Solaris is the platform on which SAC2000 is developed, it is generally the most up-to-date version.

SGI: IRIX 6.2

PC: Linux 2.0.30

DEC Alpha: OSF/1 V3.2 (Rev. 214) (this is brand new as of 10/97. Consider it as a beta version)

Old FORTRAN versions of SAC have also been ported to HP and IBM RS6000. SAC2000 works similiarly but not identically on each of these computers. SAC2000 handles the second area, graphics, by including three different graphics devices in the code. They are:

XWINDOWS: A windowing scheme that is available on a large number of graphics workstations.

SUNWINDOW: A windowing scheme that is available on SunOS v4.X.

SGF: Stands for SAC Graphics File. Each file contains all the information needed to generate a single plot.

Each of these devices is described more fully in a later section of this manual. Check with your system administrator, if you need help.

If you have technical questions about this page, contact:
="gopher://ns.llnl.gov:105/2?peterg">Peter Goldsteinpeterg@llnl.gov -- Peter Goldstein

This page maintained by:

peterg@llnl.gov -- Peter Goldstein

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