ABSTRACT Phase identification procedures for teleseismic events at Syowa Station (69.0°S, 39.6°E; SYO), East Antarctica have been carried out since 1967 after the International Geophysical Year (IGY; 1957-1958). Since the development of INTELSAT telecommunication link, digital waveform data have been transmitted to the National Institute of Polar Research (NIPR) for the utilization of phase identification. Arrival times of teleseismic phases, P, PKP, PP, S, SKS have been detected manually and reported to the International Seismological Centre (ISC), and published by “JARE Data Reports” from NIPR. In this paper, hypocentral distribution and time variations for detected earthquakes are demonstrated over the last four decades in 1967-2010. Characteristics of detected events, magnitude dependency, spatial distributions, seasonal variations, together with classification by focal depth are investigated. Besides the natural increase in the occurrence of teleseismic events on the globe, a technical advance in the observing system and station infrastructure, as well as the improvement of procedures for reading seismic phases, could all combine to produce the increase in detection of events in last few decades. Variations in teleseismic detectability for longer terms may be possible by association with the meteorological environment and seaice spreading area around the Antarctic continent. Recorded teleseismic and local seismic signals have sufficient quality for many analyses on dynamics and structure of the Earth as viewed from Antarctica. The continuously recorded data are applied not only to lithospheric studies but also to the Earth’s deep interiors, as a significant contribution to the Federation of Digital Seismological Networks (FDSN) from high southern latitude.
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M. Kanao, D. Storchak and B. Dando, "Evaluation of Long-Period Detectability of Teleseismic Events at Syowa Station, Antarctica," International Journal of Geosciences, Vol. 3 No. 4, 2012, pp. 809-821. doi: 10.4236/ijg.2012.324082.
 K. Kaminuma, “Earthquake Detection Capability of Syowa Station, Antarctica,” Antarctic Record, Vol. 33, 1968, pp. 71-80.
 M. Kanao, K. Doi, S. Sakanaka, T. Uemura, T. Sawagaki and K. Chida, “Replacement of the Seismic Monitoring System at Syowa Station, Corresponding to the INTERSAT link,” Antarct. Rec., Vol. 50, 2006, pp. 287-303.
 M. Kanao, “Seismological Bulletin of Syowa Station, Antarctica, 1992,” JARE Data Reports, Vol. 192 (Seismology 27), 1994, pp. 1-69.
 M. Kanao, “Seismological Bulletin of Syowa Station, Antarctica, 1997,” JARE Data Reports, Vol. 236 (Seismology 33), 1999, pp. 1-65.
 Y. Aoyama and M. Kanao, “Seismological Bulletin of Syowa Station, Antarctica, 2008,” JARE Data Reports, Vol. 317 (Seismology 44), 2010, pp.1-85.
 M. Kanao, A. Kubo, T. Shibutani, H. Negishi and Y. Tono, “Crustal Structure around the Antarctic Margin by Teleseismic Receiver Function Analyses,” In: J. A. Gamble, D. N. B. Skinner and S. Henrys, Eds., Antarctica at the Close of a Millennium, Royal Society of New Zealand Bulletin, Vol. 35, 2002, pp. 485-491.
 K. Kuge and Y. Fukao, “High-Velocity Lid of East Antarctica: Evidence of a Depleted Continental Lithosphere,” Journal of Geophysical Research, Vol. 110, 2005, Article ID: B06309. doi:10.1029/2004JB003382
 M. Kanao, Y. Usui, T. Inoue and A. Yamada, “Broadband Seismic Deployments for Imaging the Upper Mantle Structure in the Lützow-Holm Bay Region, East Antarctica,” International Journal of Geophysics, Vol. 2011, 2011, pp. 1-15, doi:10.1155/2011/272646
 R. Kobayashi and D. Zhao, “Rayleigh-Wave Group Velocity Distribution in the Antarctic Region,” Physics of the Earth and Planetary Interiors, Vol. 141, No. 3, 2004, pp. 167-181.vdoi:10.1016/j.pepi.2003.11.011
 K. Nawa, N. Suda, K. Satake, T. Sato, K. Doi, M. Kanao and K. Shibuya, “Loading and Gravitational Effects of the 2004 Indian Ocean Tsunami at Syowa Station, Antarctica,” Bulletin of the Seismological Society of America, Vol. 97, No. 1A, 2007, pp. S271-278.
 M. Kanao and K. Kaminuma, “Seismic Activity Associated with Surface Environmental Changes of the Earth System, around Syowa Station, East Antarctica,” In: D. K. Futterer, D. Damaske, G. Kleinschmidt, H. Miller and F. Tessensohn, Eds., Antarctica: Contributions to Global Earth Sciences, Springer-Verlag, New York, 2006, pp. 361-368.
 M. Kanao, Y. Nogi and S. Tsuboi, “Spacial Distribution and Time Variation in Seismicity around Antarctic Plate—Indian Ocean Region,” Polar Geoscience, Vol. 19, 2006, pp. 202-223.
 T. Himeno, M. Kanao and Y. Ogata, “Statistical Analysis of Seismicity in a Wide Region around the 1998 Mw 8.1 Balleny Islands Earthquake in the Antarctic Plate,” Polar Science, Vol. 5, No. 4, 2011, pp. 421-431,
 U. Usui, Y. Hiramatsu, M. Furumoto and M. Kanao, “Thick and anisotropic D″ layer beneath Antarctic Ocean,” Geophysical Research Letters, Vol. 32, 2005, Aricle ID: L13311, doi:10.1029/2005GL022622
 Y. Usui, M. Kanao, A. Kubo, Y. Hiramatsu and H. Negishi, “Upper Mantle Anisotropy from Teleseismic SKS Splitting Beneath Lützow-Holm Bay Region, East Antarctica,” US Geological Survey and the National Academies, 2007.
 Y. Usui, Y. Hiramatsu, M. Furumoto and M. Kanao, “Evidence of Seismic Anisotropy and a Lower Temperature Condition in the D″ layer beneath Pacific Antarctic Ridge in the Antarctic Ocean,” Physics of the Earth and Planetary Interiors, Vol. 167, No. 3-4, 2008, pp. 205-216.
 T. Isse and I. Nakanishi, “Inner-Core Anisotropy Benearth Australia and Differential Rotation,” Geophysical Journal International, Vol. 151, No. 1, 2001, pp. 255-263.
 G. Toyokuni, H. Takenaka, M. Kanao, D. A. Wiens and A. A. Nyblade, “Comparison of Global Synthetic Seismograms Calculated Using the Spherical 2.5-D Finite- Difference Method with Observed Long-Period Waveforms Including Data from the Intra-Antarctic Region,” Polar Science, Vol. 6, No. 2, 2012, pp. 155-164.
 M. Kanao, “Detection Capability of Teleseismic Events Recorded at Syowa Station, Antarctica 1987-2007,” Antarctic Record, Vol. 54, 2010, pp. 11-31.
 M. Kanao and K. Kaminuma, “Broad-Band and Wide Dynamic-Range Seismic Observations with a Streckeisen Seismometer (STS) at Syowa Station, East Antarctica,” Antarctic Record, Vol. 37, 1993, pp. 291-318.
 M. Kanao, K. Kaminuma, K. Shibuya, Y. Nogi, H. Negishi, Y. Tono and T. Higashi, “New Seismic Monitoring Observation System and Data Accessibility at Syowa Station,” Antarctic Record, Vol. 43, No. 1, 1999, pp. 16-44.
 T. Hagiwara, “A Note on the Theory of the Electromagnetic Seismograph,” Bulletin of the Earthquake Research Institute, Vol. 36, 1958, pp. 139-164.
 K. Kaminuma, T. Eto and M. Yoshida, “Seismological Observation at Syowa Station, Antarctica,” Antarctic Record, Vol. 33, 1968, pp. 65-70.
 G. Streckeisen and A. G. Messegeraete, “Very-Broad-Band Feedback Seismometers STS-1V/VBB and STS-1H/VBB Manual,” 1987, pp. 34-35.
 K. Nagasaka, K. Kaminuma and K. Shibuya, “Seismo- logical Observations by a Three-Component Broadband Digital Seismograph at Syowa Station, Antarctica,” In: Y. Yoshida, K. Kaminuma and K. Shiraishi, Eds., Recent Progress in Antarctic Earth Science, Terra Scientific Publishing,, Tokyo, 1992, pp. 595-601.
 B. L. N. Kennett, “IASPEI 1991 Seismological Tables,” Terra Nova, Vol. 3, No. 2, 1991, p. 122.
 S. Ushio, “Frequent Sea-Ice Breakup in the Lützow-Holmbukta, Antarctica, Based on Analysis of Ice Condition from 1980 to 2003,” Antarctic Record, Vol. 47, No. 3, 2003, pp. 338-348.
 F. Ringdal, “Study of Magnitudes, Seismicity and Earthquake Detectability Using a Global Network,” Bulletin of the Seismological Society of America, Vol. 76, No. 6, 1986, pp. 1641-1659.
 S. Tsuboi, M. Kikuchi, Y. Yamanaka and M. Kanao, “The March 25, 1998 Antarctic Earthquake: Great Earthquake Caused by Postglacial Rebound,” Earth Planets Space, Vol. 52, No. 2, 2000, pp. 133-136
 K. Kaminuma, “A Revaluation of the Seismicity in the Antarcitc,” Polar Geoscience, Vol. 13, 2000, pp. 145- 157.
 A. M. Reading, “On Seismic Strain-Release within the Antarctic Plate,” In: D. K. Futterer, D. Damaske, G. Kleinschmidt, H. Miller and F. Tessensohn, Eds., Antarctica: Contributions to Global Earth Sciences, Springer-Verlag, New York, 2006, pp. 351-356
 K. Kaminuma and J. Akamatsu, “Intermittent Micro-Seismic Activity in the Vicinity of Syowa Station, East Antarctica,” In: Y. Yoshida, K. Kaminuma and K. Shi-raishi, Eds., Recent Progress in Antarctic Earth Science, Terra Scientific Publishing, Tokyo, 1992, pp. 493-497.
 S. Anandakrishnan and R. B. Alley, “Tidal Forcing of Basal Seismicity of Ice Stream C, West Antarctica, Observed Far Inland,” Journal of Geophysical Research, Vol. 102, No. B7, 1997, pp. 15,183-15,196.
 G. Ekstr?m, M. Nettles and V. C. Tsai, “Seasonality and Increasing Frequency of Greenland Glacial Earthquakes,” Science, Vol. 311, No. 5768, 2006, pp. 1756-1758.
 M. Nettles and G. Ekstro?m, “Glacial Earthquakes in Greenland and Antarctica,” Annual Review of Earth and Planetary Sciences, Vol. 38, 2010, pp. 467-491.
 X. Chen, P. M. Shearer and F. Walter, “Seventeen Antarctic Seismic Events Detected by Global Surface Waves and a Possible Link to Calving Events from Satellite Images,” Journal of Geophysical Research, Vol. 116, 2011, Article ID: B06311. doi:10.1029/2011JB008262
 A. Yamada, M. Kanao and M. Yamashita, “Features of Seismic Waves Recorded by Seismic Exploration in 2002: Responses from Valley Structure of the Bedrock Beneath Mizuho Plateau,” Polar Geoscience, Vol. 17, 2004, pp. 139-155.
 M. Kanao, A. Maggi, Y. Ishihara, M.-Y. Yamamoto, K. Nawa, A. Yamada, T. Wilson, T. Himeno, G. Toyokuni, S. Tsuboi, Y. Tono and K. Anderson, “Interaction on Seismic Waves between Atmosphere-Ocean-Cryosphere and Geosphere in Polar Region,” In: M. Kanao, H. Takenaka, Y. Murai, J. Matsushima and G. Toyokuni, Eds., Seismic Waves—Research and Analysis, Intech Publishing, Rijeka, 2012, pp. 1-20.
 K. Kaminuma and H. Chiba, “The New Seismographic Vault and the Detection Capability of Syowa Station, Antarctica,” Antarctic Record, Vol. 46, 1973, pp. 67-82.
 M. Kanao and K. Kaminuma, “Detection Capability of Earthquakes Recorded at Syowa Station, Antarctica, from 1987 to 1993,” Antarctic Record, Vol. 39, 1995, pp. 156-169.
 R. Butler and K. Anderson, “Global Seismographic Network (GSN),” IRIS Annual Report, 2008, pp. 6-7.
 B. Romanowicz, J. F. Karczewski, M. Cara, P. Bernard, J. Borsenberger, J. M. Cantin, B. Dole, D. Fouassier, J. K. Koenig, M. Morand, R. Pillet and D. Rouland, “The Geoscope Program: Present Status and Perspectives,” Bulletin of the Seismological Society of America, Vol. 81, No. 1, 1991, pp. 243-264.
 S. Tsuboi, “Poseidon (PACIFIC21),” IRIS Newsletter, Arlington, 1995, pp. 8-9.
 D. Rouland, C. Condis, C. Parmentier and A. Souriau, “Previously Undetected Earthquakes in the Southern Hemisphere Located Using Long-Period Geoscope Data,” Bulletin of the Seismological Society of America, Vol. 82, No. 6, 1992, pp. 2448-2463.