The PNSN operates a heterogeneous 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.
- Short Period - Identified in seismograms with the suffix "EHZ" - sensitive velocity seismometers with a response peaked around 1 Hz. Typically only a single vertical component. Primarily used for determination of locations and magnitudes of small regional earthquakes.
- Broadband - Identified in seismograms by suffixes: "BHZ" or "HHZ" (Vertical), "BHE" or "HHE" (East-West horizontal), or "BHN" or "HHN" (North-South horizontal - velocity seismometers with a wide frequency response. Primary purpose is to record waveforms from regional and distant earthquakes for research purposes.
- Strong Motion Identified in seismograms by suffixes: "ENZ" or "HNZ" (Vertical), "ENE" or "HNE" (East-West horizontal), and "ENN" or "HNZ" (North-South horizontal) - accelerometers with three components. Designed to record on-scale waveforms from moderate and large regional earthquakes that give rise to strong shaking.
"Earthworm" DATA COLLECTION NODES
The PNSN operates several field computers that collect and digitize data for telemetry via internet. These are shown in station maps as blue "eworm" circles. These nodes operate the same software used in the PNSN Seismology Lab, which is also shown as a blue circle.