SlimLine 4.5 Hz Borehole Geophone – Fixed

The AF4.5 is ASIR's readily deployed three-component 4.5 Hz borehole geophone designed for high-resolution shallow borehole and posthole seismic monitoring. Optimized for installations up to 100 m deep, the sensor combines high sensitivity, a compact 51 mm diameter, and robust long-term reliability for permanent or temporary deployments. The AF4.5 is well suited for local earthquake monitoring, microseismic studies, engineering seismology, infrastructure monitoring, and scientific research.

Advanced Features

• extra slim 51 mm outer diameter (OD)
• passive geophone sensors
• for permanent or temporary installations

Application & Deployment

• Small, 6 to 18 station, local monitoring network in up to 100 m deep, < 3° tilted, boreholes
• Stations spaced 3 to 5 km apart for approximate event locations to within 200 to 400 meters
• Improves detection by 1 unit of magnitude over surface networks, detecting and locating all M > ~ 0.5

Dimensions

Outer diameter	51 mm
Length	420 mm
Weight	2.6 kg
Power requirement	-