JOHN - STATION INSTRUMENTATION

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

DATES OF OPERATION: 24 July 1998 to Present.

SEISMOMETER TYPE AND ADC:
Guralp CMG3-T-B borehole seismometer for broad-band channels (00 and 01 location
codes). Streckeisen STS-2 seismometer for for higher sample rate broad-band channels
(10 location codes). Kinemetrics FBA-23 Low-Gain sensor for 10 channels. ADC
Quanterra Q-680, 12 channel.

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) channels. Range: +8,388,607 to -8,388,608
counts. 24-bit integer data words for very short period (80 sps) data continuous very
short period (40 sps) data.

EVENT DETECTOR ALGORITHM:
The Murdock/Hutt event detector (Murdock, 1991) is used for the HN? and HH? channels.

Channel Data