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When QuakeManager is installed, it installs a ground motion library folder on your disk, and during the installation it will ask you to confirm the location for that folder. By default, this folder is C:\GMLibrary\, and the following are the files and folder that will be installed in the GMLibrary folder:
•File: QMDB.sdf -> This is the actual ground motion database file where the metadata for all records is stored. Note that the database does not include the actual recorded acceleration histories, it only includes metadata about the records, including information about the earthquake event, the recording station, the processing of the record, and so on. It also includes 40 different intensity measures including PGA, PGV, PGD, etc and spectral values, all of which are valuable to have in the database when you are searching and filtering and trying to find the best candidates for your ground motion selection, scaling and modification.
•Folder: SACSteel -> This is where the all SACSteel ground motion recorded acceleration files are installed by QuakeManager. If you go into the sub-folders (e.g. LA 10 in 50), you will see ground motion acceleration files each representing one component of a record. If you open one of them, you will see that this is the actual ground motion acceleration data.
•Folder: NGA-West2 -> QuakeManager installs this empty folder for the NGA-West2 ground motions. This is a placeholder folder for storing NGA2 ground motion files that can be downloaded from the PEER NGA website. All downloaded NGA records go in the same folder, which makes them easier to manage.
The ground motion database file (.sdf) stores the following information:
1.The records' metadata fields.
2.Information about the collection objects, that act like virual folders, and are used to organize the records,
3.Computed response spectra and intensity measures of the records
The acceleration histories are NOT saved within the database. Instead, the database contains information about the location (path and files names) of the acceleration data on the user's disk. This helps keep the size of the database (.sdf) file manageable. Once the spectra of the records are computed by the program, they are automatically saved in the database (the user can set the Options for deciding which spectral quantities to automatically save to the database). This makes it possible to:
•Quickly load the cached spectra from the database without having to recompute them every time.
•Perform ground motion selection with records even if the acceleration history files are not available on disk (this makes it handy, for example, to search the NGA database, or other databases that cannot be fully downloaded or are too large to distribute); The user could then download only the records they need.
Keeping the above folder structure in mind, now you know that all the records in the ground motion library live in the ground motion database file (QMDB.sdf), so don't move it, delete it or rename it because QM won't be able to find it. If you DO want to move this file, it is possible to specify within QuakeManager that the location has changed. This is done under the Options dialog (accessed from the file menu), which offers two file locations that can be customized. The first location is a default folder for all ground motion data (default is C:\GMLibrary\), and the other is the location of the Ground Motion Database (GMDB) file (default is C:\GMLibrary\QMDB.sdf).
So when you click on a collection in the GM Library, QuakeManage retrieves data from the Database file (.sdf) and shows the records contained within it. If the ground motion acceleration files are available on disk, QM will find them, for example LA01, and load their acceleration history data and show it on the acceleration chart. QuakeManager will also automatically compute the spectra and intensity measures on the fly, which will then be automatically saved to the database and made available for future search. This makes the database a Self-Building Database, because it is able to build itself internally automatically without the need for external analysis software.
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