Broadband Seismometer Workshop

• Main Authors: Richard Warburton, Gwr Instruments, Esashi Membach
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Balleny Islands
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.523.7926; http://www.iris.washington.edu/stations/seisWorkshop04/PDF/GWRPoster.pdf

Recent studies have demonstrated that the best superconducting gravimeters (SGs) are less noisy than the STS-1 seismometers for frequencies below 1.0 mHz. Examples include measurement of the torsion modes 0T2 to 0T4 after the Balleny Islands Mw = 8.2 earthquake on March 25,1998 (Zürn et al., 2000), and measurement of 1S2 and the splitting of 0S2 after the Peru Mw = 8.4 earthquake on June 23, 2001 (Rosat et al., 2003). However, for frequencies above 1.5 mHz, the STS-1 and ET-19 at BFO are less noisy than SGs. This is confirmed in studies of the hum at Canberra (Australia) where an STS-1 and SG are collocated. In the hum band (2 to 7 mHz) the STS-1 is ≈ 7 dB lower and ET-19 is ≈ 4 dB lower than the best SGs. Figure 1: Spectra from the 2001 Peru event for which seven SG stations (Canberra