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7.13.3 Degtra A4

Degtra A4 is a Windows-based computer system designed to process ground-motion time histories for seismology, engineering seismology and earthquake engineering applications. It has been developed at the Institute of Engineering, UNAM, Mexico, where it has been used as a professional and teaching tool for more than 10 years. Figure 7.22 shows a typical view of Degtra A4.

Figure 7.22: Example of DEGTRA A4.
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Degtra A4 accepts input ground-motion recordings written in several formats: simple ASCII or binary files, SEISAN format and the standard format of the Mexican Strong-Motion Database.

The program has a nice and user-friendly interface, in which several time-histories can be manipulated at a time. It includes zoom-in/zoom-out capabilities that can be used if only a portion of a recording is of interest.

There are two types of operations that Degtra A4 can perform using strong-motion recordings: operations involving a single recording and operations involving two recordings.

Among the first group, the main functions are the following:

The main operations involving two recordings are:

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Spectral ratio. Computes the (Fourier) spectral ratio between two recordings.
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Odogram. Displays an X-Y parametric representation (time is the parameter) of two recordings, typically ground displacements, in order to observe particle trajectories.
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Addition/Difference. Computes the sum or difference of two recordings. This is useful, for instance, to identify rocking or torsional motions in buildings.
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Rotation: Rotates two components of the ground motion to arbitrary angles.
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Cross-correlation: Computes cross-correlation between two signals.
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Coherence: Computes coherence between two signals.

Degtra A4 includes an on-line help file with details about the meaning of required parameters, techniques used, and use of Degtra A4 itself. It is available in two versions: one for Windows 2000 or lower and another for Windows XP. Installation is made with a typical Windows executable setup file. The distribution is found in directory SUP.

Degtra A4 is currently in Spanish, English version in preparation.

For questions please contact:

Mario Ordaz, Institute of Engineering, UNAM
mors@pumas.iingen.unam.mx


next up previous contents index
Next: 7.14 Calculating b-value, BVALUE Up: 7.13 Signal processing programs Previous: 7.13.2 SAC2000   Contents   Index
Peter Voss : Mon Apr 14 15:48:55 CEST 2014