Scream! 4.5 is a software application for seismometer configuration, real-time acquisition and monitoring. It runs on Linux and Windows (from 98 onwards). It can be used for decompressing, viewing, printing, recording, transmitting and replaying GCF data from any Güralp Systems digital device.
Scream! 4.5 can be used in two modes:
as a stand-alone, real time application for real-time data acquisition, including a network server and client, file replay, recording and analysis tools; or
as a “helper” application for viewing pre-recorded GCF files, which also allows you to convert data formats and launch analysis tools.
When you run Scream! by double-clicking on its icon, or by launching it from the command line, it opens a main window showing all the data streams coming in.
Scream! can listen for streams in GCF format on local serial ports or network interfaces.
The main window is the control centre for the whole program. If you close this window, Scream! will quit. All of Scream!'s functions are invoked from this window: see Chapter 3.
You can view a data stream by opening a Waveview window for it. Any number of Waveview windows can be opened, each containing any number of streams. The same stream can appear in several Waveview windows, if desired. Each Waveview window has its own amplitude and time scaling, colour scheme, and display parameters. For example:
a data stream can be viewed simultaneously at different zoom factors in different windows;
different groups of data streams can be viewed simultaneously, each group having the same zoom factor; or
an entire array can be monitored in one window, using another for detailed examination of incoming data.
Waveview windows provide simple filtering capabilities, allowing you to examine seismic signals in a particular frequency range of interest. When more detailed analysis is required, data can be passed to a range of Scream! extensions with a simple selection.
Waveview windows are fully described in Chapter 4; Scream! extensions are covered in Chapter 12.
Scream! performs extensive checks on all incoming GCF data, and logs errors to disk. You can see details about the incoming data, including any errors detected by Scream!, using ShowInfo, Network Control, Summary and Status windows. These are described in Chapter 6.
Scream! also provides logging facilities, and can e-mail operators when a potential problem is detected. See Chapter 11.
Scream! provides an easy-to-use graphical interface for configuring Güralp Systems digitisers. Output streams, triggering, calibration and mass control can all be managed by Scream!.
See Chapter 7 and Chapter 8 for more information on these features.
The real time Scream! application provides a built-in network server and client for data in GCF format. A Network Control window provides full control of Scream!'s network connections. The Scream! server can be configured to allow remote clients to configure digitisers and control instruments over the network.
Chapter 5 describes the networking functions Scream! offers.
You can instruct Scream! to record data to disk with the click of a button. Scream! supports GCF, SAC, miniSEED, SEGy, PEPP, SUDs and GSE formats, among others, allowing you to transfer the data quickly and easily for further analysis or processing.
GCF data files, including data from Güralp Systems NAM, EAM or DCM units, can be read, replayed at variable time-scales, viewed, converted or printed with a few mouse clicks.
Support for SCSI tape devices is also included for secondary backup or large volume archival.
See Chapter 9 and Chapter 10 for details of these features.
Scream! can also be run in a slimmed-down viewing mode, which loads in a GCF file, selection of files, or a directory containing files, and displays the data in a Waveview window.
To use these features:
Double-click on a GCF file to open a WaveView window showing the data in the file.
Any valid GCF file can be loaded, including multi-stream files and files with gaps or out-of-order data.
To open a WaveView window showing all the data in several GCF files, select the files, right-click and choose View in Scream from the pop-up menu.
To search one or more directories for GCF files and display all the data in these files, select the directories, right-click and choose View in Scream.
WaveView windows opened this way behave exactly like windows from the real-time application, except that the “pause” button () is replaced with a button which resets the view to its initial settings.
You can design and apply filters, draw spectrograms, or send data to Scream! extensions just as you would from real-time Scream!. See Chapter 4, for full details of what you can do.
From the command line, Scream! can be run in viewing mode with
scream -view filename [filename…]
Scream! cannot switch between real-time mode and viewing mode. If you want to load GCF files into the real-time application, you should use the Replay Files facility (see Section 9.3). However, you can have both real-time Scream! and Scream! viewer windows open at the same time.