Seismological Bulletin of Syowa Station, Antarctica, 2002

Research Expedition (JARE-43).He also scaled the arrival times for seismic events and reported to ISC and USGS through that wintering season.In this data report, we would like to introduce the seismic observations at present in 2002, scaled read-out travel-time data and detected teleseismic earthquake list, in addition to the procedures for public use by Internet service. ObservationsThe seismic observation systems at Syowa Station were all replaced to the current ones by one of the authors in 1997 (Kanao, 1999).The block diagram of the new recording system is illustrated in Fig. 3. Seismographic but and seismographsSeismic observations at Syowa Station had been carried out mainly by two types of seismometers,one called a short-period (HES) with 1.0 s natural period of the pendulum and it had been operated since 1%7 (Kaminuma et al., 1%8).The overall frequency responses and the magnifications of the HES are shown in Fig. 4. A three-component broadband seismometer (Streckeisen STS-1) with the digital recording system has been operating since 1990 (Nagasaka el al., 1992).The amplitude and phase responses for the velocity output (fuoadl!and; BRB) are shown in Fig. 5 (after Streckeisen and Messegeraete, 1987).The new seismographic hut was constructed m 1996 and the whole sensors were moved inside it in 1997.The new hut is located about 200 m north from the old vault, with geodetic coordinates of 69"00'24.0"S,39"35'06.0"Eand the elevation is 20 m above mean sea level.Since the broadband seismographs are largely affected by a change of temperature and atmospheric conditions, the sensor room was covered doubly by adiabatic walls.with a surface covered by titanium to keep constant temperature in the room.'O ' ., [0SR/W386 software] AD converter !Table 1.List of phase arrival-time data in 2002.