The PNSN operates and maintains a variety of seismograph equipment at hundreds of individual sites in Washington and Oregon. Each site has one or more seismometers, an electronics package, a power source, and telemetry equipment to send the signal back to the PNSN Seismology Lab at the University of Washington. At the Seismology Lab, the signals recieved from the field are decoded and analyzed. All of this requires a whole bunch of equipment and software both in the field and in the lab.
PNSN STATION LOCATIONS AND SEISMOMETER TYPES
The PNSN operates a heterogenious mix of seismometer types for
monitoring a variety of types of earthquake activity. The
operations of seismographs are funded by different agencies
and serve a variety of purposes.
TELEMETRY
- Analog Telemetry - Continuous real-time Analog signals are produced by the short-period seismometers in our network. These signals are telemetered through FM (frequency modulated) radio technology. A VCO (voice coded oscillator) transforms the seismometer signal into frequency variations of a FM carrier frequency. The FM signal may be carried by radio waves, microwave, telephone line, or T-1 communications cable. At the Seismology Lab, a "Discriminator" is used to separate the signal from the carrier. Analog signals must be digitized and time stamped before they can be combined with other data.
- Digital Telemetry - Broad-band and Strong Motion instruments in the PNSN are equipped with electronics packages that digitize and time-stamp the data at each local site. Digital data is sent to the PNSN Seismology Lab via leased-line modems or Internet connections.
DATA ACQUISITION SYSTEM
The PNSN uses the USGS EARTHWORM data acquisition system to merge, manage, record and automatically pre-process digital data.
USGS SOFTWARE
ELECTRONICS AND ENGINEERING
PNSN Operations requires a whole bunch of equipment and software.
REPORTS AND CATALOGS
PNSN Earthquake Locations and discussion are found in the CATALOGS & DATA section.
