3. Seismic Research Observatory - SRO:  [ SR ]

DATES OF OPERATION: 	11 Apr 1985 to 21 Nov 1988.

VAULT CONDITIONS: The seismometers are located in the concrete pit directly over
the borehole.  The pit is about 5 feet square and 5 feet deep and is lined with
styrofoam.  After seismometer installation the pit was filled with the styrofoam
pellets and covered with a metal roof.  Unfortunately heavy rains caused water to
accumulate in the pit resulting in downtime and excessive maintenance.

SEISMOMETER TYPE:
Streckeisen Model STS-VBB 3 component.

DIGITAL FORMAT:
16 bit gain-ranged data words for all components.   Range: +2,096,128 to -2,097,152.

EVENT DETECTOR ALGORITHIM:
The Murdock event detector (Murdock, 1983) was used for the short-period 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:
The original Teledyne-Geotech borehole seismometer was replaced with Streckeisen
broad-band seismometers under an exchange agreement with the State Seismological
Bureau of China.  The surface seismometers proved to be too noisy for the 
observatory environment at Guam, and the seismometers were eventually replaced with
another borehole seismometer.  These seismometers are 100 meters higher in
elevation than the borehole system.