Universidad de Chile, Servicio Sismologico. 01/07/05-01/08/05
Department of Geoscience
University of Bergen
Phone: (+47) 55 58 36 00
Fax: (+47) 55 58 36 60
Introduction. The cooperation with the Universidad de Chile, Servicio Sismologico, started back in 1992. In October 1999, the cooperation was formalized through a memorandum of understanding between The Department of Geophysics, University of Chile, Santiago, Chile and The Institute of Solid Earth Physics, University of Bergen, Bergen, Norway.
Through the years there have been several visits to Chile to implement the QNX SEISLOG, SEISAN and SEISNET environment for data acquisition, data analysis and communication, and Chile has the largest network using the SEISLOG software.
Servicio Sismologico now has around 40 QNX SEISLOG systems installed, from Iquique in the north to Puerto Mont in the south. A total of around 125 channels are recorded.
Chile has a very high seismic activity, and a lot of events are detected every day, and therefore an interesting place to test out and improve our systems.
The trip was done after an invitation from Servicio Sismologico. All expenses for tickets and stay in Chile were paid by Servicio Sismologico.
The purpose of the visit.
Implement new drivers for Seislog Linux
Test SEISLOG Linux in a high seismicity area
Implement SEISINFO and DISPLAY at Servicio Sismologico
New drivers for Seislog Linux. Five digitiser drivers were implemented and tested during the stay. Some digitisers have the time integrated in the data format and others not. For digitisers with no timing, the CPU time is used. The CPU time is continuously adjusted by the ntpd time server demon. Installation is explained in the documentation.
Drivers for: GBV-316
TDT, Ortiz & Aranda
Test installation of Seislog Linux. The PC104 with the Knopix version of Linux was used as a test system. SEISLOG was installed without the X user interface.
The 16-channel SADC30 digitiser from Sara was connected in parallel to the analogue signals on the existing SEISLOG QNX 2.
No GPS was connected to test the accuracy of the ntpd time-server.
SEISLOG was running for several days without any problems and detected the same events as the SEISLOG 2 QNX system. It turns out that the ntpd time-server in the Linux Knopix version stops after some time. It synchronizes the CPU time, but it doesn’t keep the CPU time synchronized over time. This works fine in the Fedora and Mandrake versions of Linux.
Signals from one station were monitored from other PCs with the program DISPLAY.
DISPLAY is the same program that is used to monitor data from the Global Seismograph Network. SEISLOG includes a server function that simulates the output format from the Live Internet Seismic Server (LISS).
Monitoring PC. A second PC was installed in the recording room to provide a monitoring facility for the SEISLOG system. The DISPLAY program runs continuously showing one channel of data in a helicorder fashion.
In addition the SEISINFO program was installed to monitor world seismicity and/or signals from the Limon Verde station. A modification was made in the program to show the map and statistics from the last felt event in Chile.
Documentation. The first version of the user manual for SEISLOG Linux is under preparation.
This version of SEISLOG seems to be stable and functioning well with the digitisers described above. More or less the same events are detected and recorded as for the old QNX version.
Timing for this version of SEISLOG can be done in two ways:
CPU time as set by the user or synchronized by the ntpd.
Time from GPS integrated with digitiser. For this version there is no warning when the GPS clock is out of synchronization. The digitiser’s internal clock is then used. This clock will normally be accurate until the next GPS synchronization.
The ntpd server seems to be working differently on different versions of Linux. On Fedora and Mandrake it keeps on synchronizing the CPU clock “forever”, while in Knopix, it stops after a while. This must be investigated for future versions.
Parameter files are written as ascii files and can only be modified using a text editor. This option will be available also in future versions to be able to run SEISLOG without any graphic user interface. However, a more user friendly parameter program should be included.
The DISPLAY program should include an option to select any component for plotting.
Modify SEISINFO to include a separate selection box for options. For example “last felt event in Chile” or “monthly report events”
Finish first version of documentation.
Investigate cheap, low power, diskless Seislog Linux. Servicio Sismologico is now using the PC104 system with hard disk as field systems with the old SEISLOG QNX version. The system works fine, but is consuming much power and is relatively expensive.
Servicio Sismologico would also like to install educational systems at schools and also in museums in Chile, but will need assistance to make the necessary modifications in the programs.