Data Services Newsletter

Volume 12 : No 1 : Spring/Summer 2010

SAC Software Statistics

Five Years of Distributing the Seismic Analysis Code Software

SAC (Seismic Analysis Code) is a general purpose interactive program designed for the study of sequential signals, especially timeseries data. This article highlights the distribution statistics for SAC software over five years, from 2005-2009.

In 2005, IRIS started distributing the SAC software to IRIS members. In late 2006, IRIS expanded the licensing agreement, allowing the distribution of SAC software to collaborators including the USGS, members of FDSN and other non-U.S. seismological institutes. The new license agreement led to a large increase in the number of SAC requests each year. Between 2006 and 2007, there was a 237% increase in SAC distributions (see chart below).

SAC software distribution by year
Figure 1: SAC software distribution by year

SAC software distribution by year and country
Figure 2: SAC software distribution – USA vs. Non-USA

International demand for the SAC software increased following a new license agreement in 2006. The number of SAC requests started to level off in 2009.

SAC Distribution by Platform

There have been over 3,700 SAC Software requests by scientists and programmers from Feb 2005 to April 2010. The program has gone through several revisions and many scientists request the latest version. SAC is available for Linux, Mac and Solaris computer platforms.

SAC software distribution by platform
Figure 3: SAC software distribution by platform

The majority of users request the Linux binary (58%), followed by Mac (29%) and Solaris (13%). The SAC source code is requested by 69% of the users.

SAC distribution by country

SAC distribution by country

Seismologists worldwide use the SAC software distributed by the IRIS DMC. Hover over the interactive map to view the number of SAC distributions by country . Click on a country to zoom in or click on the water to zoom out.

38% of SAC requests come from the USA, while 62% of the requests come from other countries. The total number of SAC requests from China, Japan, Italy and other countries conducting seismic research is displayed in the chart below (2005-2010).

SAC Distributions – International

SAC software international distribution
Figure 4: SAC software distribution – International

SAC Distribution by State

SAC distribution by state

SAC has been requested by hundreds of researchers and college students in 42 states. Hover over a state to see the number of SAC distributions. Darker colors represent a higher number of distributions. (Feb 2005 – April 2010).

SAC Distribution – Top Ten States

SAC software distribution top ten states
Figure 5: SAC software distribution – top ten states. California leads all states in SAC requests over five years.

SAC Requests by Job Title

SAC software distribution job title
Figure 6: SAC software distribution – by job title. SAC users include students, professors, scientists, engineers and programmers.

Requesting SAC Software

A scientist can request the SAC software using the online request form. Once a request is received the information is reviewed by IRIS staff. If information is missing, then a special notice is sent by email asking the user to complete the form. A completed form is typically processed in within one to three days, and if accepted the SAC binaries and installation instructions are sent to the user by email.

Who can request SAC

In addition to IRIS Members and Affiliates, IRIS may also distribute the SAC Software to collaborators such as the U.S. Geological Survey, Air Force Technical Applications Center, members of the International Federation of Digital Seismograph Networks and other non-U.S. seismological institutes (subject to export control) who are involved in relevant research projects with IRIS. The SAC Software is available free through IRIS.

More information

by Tim Knight (IRIS Data Management Center)

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