1. Global Seismograph Network - GSN: IRIS -2 System

DATES OF OPERATION:  	12 Jul 1991 to Present.

SEISMOMETER TYPE AND ADC:
Streckeisen Model STS-1/VBB 3 component system.  Geotech Model GS-13 3 component 
seismometer system for very short period data.  ADC is Quanterra Model Q-52K.

DIGITAL FORMAT:
24 bit integer data words for all broad-band (20 sps), long period ( 1 sps), 
very long period (0.1 sps) and ultra long period (0.01 sps) components.  
Range: +8,388,607 to -8,388,608 counts.  16 bit integer data words for very
short period and mass position channels.  Range: +32767 to -32768

EVENT DETECTOR ALGORITHM:  
The Murdock event detector (Murdock, 1991) is used for the EH_ components. 

Click on any of the following items for further information.

• Channel Data
• Amplitude Response to Ground Velocity
• Seismic Noise Study graph information
  • Seismic Noise Level - Annual
  • Seismic Noise Level - Seasonal/Diurnal

COMMENTS:
A description of the IRIS-2 system can be found in USGS Open-File Report 89-471, Peterson et al (1989).  This station was installed in Jully, 1991.  However, political 
unrest and resultant power problems have resulted in sporadic data with 
frequent long gaps.  GNI is not an open station due to communication 
difficulties in Armenia.