A decade of GEONET: 1994–2003 —The continuous GPS observation in Japan and its impact on earthquake studies—

The dense continuous GPS network of Japan, now called GEONET, has been operated since 1994 by the Geographical Survey Institute. GEONET provides precise daily coordinates of all the stations, with which displacement rates and strain rates are calculated nationwide. Various characteristics of tectonic deformation in the Japanese Is-lands have been revealed. GEONET is also quite useful in earthquake studies, precisely detecting co-seismic, post-seismic, and inter-seismic deformation signals. These observations are utilized to infer physical processes at earthquake sources. Slow slip events on plate boundaries have been found from GPS data. Such slow events provide an important constraint on the mechanism of faulting. On the other hand, there has been no success in detecting pre-seismic deformation. Lack of a precursory signal before the 2003 Tokachi-Oki (M8.0) earthquake has posed a serious question to short-term earthquake prediction. GEONET enables a good linkage between monitoring and modeling studies, opening a possibility of practical data assimilation. For further contribution to earthquake studies, it is necessary to continue GEONET with high traceability on the details in observation and analysis.

[1]  S. Miyazaki,et al.  Joint inversion of strong motion and geodetic data for the source process of the 2003 Tokachi-oki, Hokkaido, earthquake , 2004 .

[2]  T. Sagiya.  Interplate coupling in the Tokai District, central Japan, deduced from continuous GPS data , 1999 .

[3]  Kosuke Heki,et al.  Crustal velocity field of southwest Japan: Subduction and arc‐arc collision , 2001 .

[4]  S. Miyazaki,et al.  Interplate coupling in northeast Japan deduced from inversion analysis of GPS data , 2000 .

[5]  Kiyoo Mogi,et al.  Temporal variation of crustal deformation during the days preceding a thrust-type great earthquake — The 1944 Tonankai earthquake of magnitude 8.1, Japan , 1984 .

[6]  T. Sagiya,et al.  Crustal deformation caused by magma migration in the northern Izu Islands, Japan , 2001 .

[7]  S. Miyazaki,et al.  Present-day deformation across the southwest Japan arc: Oblique subduction of the Philippine Sea plate and lateral slip of the Nankai forearc , 2003 .

[8]  M. Hashimoto.  Horizontal Strain Rates in the Japanese Islands during interseismic period deduced from Geodetic Surveys (Part I): Honshu, Shikoku and Kyushu@@@本州・四国・九州 , 1990 .

[9]  Kelin Wang,et al.  A Silent Slip Event on the Deeper Cascadia Subduction Interface , 2001, Science.

[10]  Masayuki Kikuchi,et al.  Co‐seismic slip, post‐seismic slip, and largest aftershock associated with the 1994 Sanriku‐haruka‐oki, Japan, earthquake , 2003 .

[11]  Hiromichi Tsuji,et al.  Coseismic crustal deformation from the 1994 Hokkaido‐Toho‐Oki Earthquake Monitored by a nationwide continuous GPS array in Japan , 1995 .

[12]  L. Ruff,et al.  Total analysis of the 1993 Hokkaido Nansei‐Oki Earthquake using seismic wave, tsunami, and geodetic data , 1995 .

[13]  Yoichi Ooi,et al.  Dense GPS Array observations across the Atotsugawa fault, central Japan , 2003 .

[14]  Christian Rocken,et al.  Improvement of the analysis strategy of GEONET , 2003 .

[15]  S. Miyazaki,et al.  Inter-plate Coupling Along the Nankai Trough and Southeastward Motion Along Southern Part of Kyushu , 1999 .

[16]  T. Haraguchi,et al.  Timing and Recurrence Interval of the Taisho-type Kanto Earthquake, Analyzing Holocene Emerged Shoreline Topography in the Iwai Lowland, the Southwestern Part of the Boso Peninsula, Central Japan , 2001 .

[17]  J. C. Savage.  A dislocation model of strain accumulation and release at a subduction zone , 1983 .

[18]  D. Jackson,et al.  A block-fault model for deformation of the Japanese Islands derived from continuous GPS observation , 2000 .

[19]  D. Jackson,et al.  Plate tectonics and crustal deformation around the Japanese Islands , 1993 .

[20]  S. Ozawa.  Geodetic inversion for the fault model of the 1994 Shikotan Earthquake , 1996 .

[21]  A. Hasegawa,et al.  Interplate quasi‐static slip off Sanriku, NE Japan, estimated from repeating earthquakes , 2003 .

[22]  S. Miyazaki,et al.  Distribution of seismic coupling on the subducting plate boundary in northeastern Japan inferred from GPS observations , 2000 .

[23]  T. Sagiya,et al.  The M6.1 earthquake triggered by volcanic inflation of Iwate Volcano, northern Japan, observed by satellite radar interferometry , 2001 .

[24]  T. Sagiya,et al.  Co-seismic Displacements of the 1995 Hyogo-ken Nanbu Earthquake , 1996 .

[25]  I. Kawasaki,et al.  Space–time distribution of interplate moment release including slow earthquakes and the seismo-geodetic coupling in the Sanriku-oki region along the Japan trench , 2001 .

[26]  T. Sagiya,et al.  Interplate coupling and relative plate motion in the Tokai district, central Japan, deduced from geodetic data inversion using ABIC , 1993 .

[27]  T. Kato,et al.  Crustal strains in the Japanese Islands as deduced from dense GPS array , 1998 .

[28]  Tim Melbourne,et al.  Periodic Slow Earthquakes from the Cascadia Subduction Zone , 2002, Science.

[29]  J. Kasahara,et al.  A significant relation between seismic activities and reflection intensities in the Japan Trench region , 2002 .

[30]  K. Shimazaki,et al.  Dislocation model for strain accumulation in a plate collision zone , 2000 .

[31]  Hiroshi Katao,et al.  Seafloor positioning system with GPS-acoustic link for crustal dynamics observation—a preliminary result from experiments in the sea— , 2000 .

[32]  X. Pichon,et al.  Full interseismic locking of the Nankai and Japan‐west Kurile subduction zones: An analysis of uniform elastic strain accumulation in Japan constrained by permanent GPS , 2000 .

[33]  Sun-Lin Chung,et al.  Mantle dynamics and plate interactions in East Asia , 1998 .

[34]  T. Matsushima,et al.  Subsurface structure and faulting of the Median Tectonic Line, southwest Japan inferred from GPS velocity field , 2002 .

[35]  Kazushige Obara,et al.  Nonvolcanic Deep Tremor Associated with Subduction in Southwest Japan , 2002, Science.

[36]  X. Pichon,et al.  Transient and permanent deformation of central Japan estimated by GPS: 2. Strain partitioning and arc–arc collision , 2001 .

[37]  Kazuro Hirahara,et al.  Measuring ground deformations with 1-Hz GPS data: the 2003 Tokachi-oki earthquake (preliminary report) , 2004 .

[38]  S. Miyazaki,et al.  A slow thrust slip event following the two 1996 Hyuganada Earthquakes beneath the Bungo Channel, southwest Japan , 1999 .

[39]  N. F. Vasilenko,et al.  The Amurian Plate motion and current plate kinematics in eastern Asia , 1999 .

[40]  J. Zumberge,et al.  Precise point positioning for the efficient and robust analysis of GPS data from large networks , 1997 .

[41]  K. Heki.  Snow load and seasonal variation of earthquake occurrence in Japan , 2003 .

[42]  Kosuke Heki,et al.  Horizontal and vertical crustal movements from three‐dimensional very long baseline interferometry kinematic reference frame: Implication for the reversal timescale revision , 1996 .

[43]  A. Hasegawa,et al.  The 2003 M8.0 Tokachi‐Oki earthquake – How much has the great event paid back slip debts? , 2004 .

[44]  Hiromichi Tsuji,et al.  Silent fault slip following an interplate thrust earthquake at the Japan Trench , 1997, Nature.

[45]  Akira Hasegawa,et al.  Slip distribution of the 2003 northern Miyagi earthquake (M6.4) deduced from geodetic inversion , 2004 .

[46]  Shimada,et al.  Imaging magma transport during the 1997 seismic swarm off the izu peninsula, japan , 1999, Science.

[47]  David D. Jackson,et al.  Crustal deformation across and beyond the Los Angeles basin from geodetic measurements , 1996 .

[48]  Shinji Toda,et al.  Evidence from the ad 2000 Izu islands earthquake swarm that stressing rate governs seismicity , 2002, Nature.

[49]  Takeshi Sagiya,et al.  The nationwide GPS array as an earth observation system , 1998 .

[50]  S. Stein,et al.  Can the Okhotsk Plate be discriminated from the North American plate , 1996 .

[51]  T. Sagiya,et al.  Continuous GPS Array and Present-day Crustal Deformation of Japan , 2000, pure and applied geophysics.

[52]  Yuki Hatanaka,et al.  Calibration of antenna-radome and monument-multipath effect of GEONET—Part 1: Measurement of phase characteristics , 2001 .

[53]  T. Sagiya,et al.  Crustal Movements Associated with the 2000 Western Tottori Earthquake and its Fault Models , 2002 .

[54]  S. Miyazaki,et al.  Interplate coupling along the Nankai Trough off southwest Japan derived from GPS measurements , 1999 .

[55]  S. Miyazaki,et al.  Periodicity of strain accumulation detected by permanent GPS Array: Possible relationship to seasonality of major earthquakes' occurrence , 2001 .

[56]  W. Holt,et al.  Intraplate deformation in the Japanese Islands: A kinematic study of intraplate deformation at a convergent plate margin , 1995 .

[57]  S. Miyazaki,et al.  Characteristic silent earthquakes in the eastern part of the Boso peninsula, Central Japan , 2003 .

[58]  Takeo Ito,et al.  A dike intrusion model in and around Miyakejima, Niijima and Kozushima in 2000 , 2002 .

[59]  T. Sagiya,et al.  Crustal deformation around the northern and central Itoigawa-Shizuoka Tectonic Line , 2002 .

[60]  A. Linde,et al.  Slow earthquakes and great earthquakes along the Nankai trough , 2002 .

[61]  David W. Simpson,et al.  Earthquake prediction : an international review , 1981 .

[62]  Yehuda Bock,et al.  Detection of arbitrarily large dynamic ground motions with a dense high‐rate GPS network , 2004 .

[63]  Y. Tamura,et al.  Short term afterslip in the 1994 Sanriku‐Haruka‐Oki Earthquake , 1997 .

[64]  T. Nishimura.  Earthquake Triggering due to Volcanic Deformation Sources in Areas East off Ito and around the Mt. Iwate Volcano , 2002 .

[65]  H. Dragert,et al.  Episodic Tremor and Slip on the Cascadia Subduction Zone: The Chatter of Silent Slip , 2003, Science.

[66]  Paul Bodin,et al.  Using 1-Hz GPS Data to Measure Deformations Caused by the Denali Fault Earthquake , 2003, Science.

[67]  J. C. Savage,et al.  Asthenosphere readjustment and the earthquake cycle , 1978 .

[68]  H. Hamaguchi,et al.  Crustal deformation associated with the 1998 seismo-volcanic crisis of Iwate Volcano, Northeastern Japan, as observed by a dense GPS network , 2000 .

[69]  Yehuda Bock,et al.  Crustal deformation measurements in central Japan determined by a Global Positioning System Fixed-Point Network , 1992 .

[70]  K. Heki.  Seasonal Modulation of Interseismic Strain Buildup in Northeastern Japan Driven by Snow Loads , 2001, Science.

[71]  M. Ohtake,et al.  Postseismic crustal deformation following the 1993 Hokkaido Nansei‐oki earthquake, northern Japan: Evidence for a low‐viscosity zone in the uppermost mantle , 2003 .

[72]  T. Sagiya,et al.  Water-weakened lower crust and its role in the concentrated deformation in the Japanese Islands , 2002 .

[73]  Y. Yagi,et al.  Co-seismic slip, post-seismic slip, and aftershocks associated with two large earthquakes in 1996 in Hyuga-nada, Japan , 2001 .

[74]  A. Hasegawa,et al.  Strain accumulation in and around Ou Backbone Range, northeastern Japan as observed by a dense GPS network , 2002 .

[75]  K. Nakamura.  Possible nascent trench along the eastern Japan sea as the convergent boundary between Eurasian and North American plates , 1983 .

[76]  T. Kato,et al.  Prediction of stress field in Japan using GPS network data , 2000 .

[77]  Elastic and inelastic strains in the Japanese Islands deduced from GPS dense array , 2000 .

[78]  T. Tabei,et al.  Common-mode Errors in the GPS Coordinates Time Series : Application of Spatial Filtering Technique , 2002 .

[79]  T. Sagiya.  Interplate Coupling in the Kanto District, Central Japan, and the Boso Peninsula Silent Earthquake in May 1996 , 2004 .

[80]  Time-dependent inversion study of the slow thrust event in the Nankai trough subduction zone , 2001 .

[81]  X. Pichon,et al.  Deformation of the Japanese Islands and seismic coupling: an interpretation based on GSI permanent GPS observations , 1998 .

[82]  S. Stein,et al.  A model for the motion of the Philippine Sea Plate consistent with NUVEL‐1 and geological data , 1993 .

[83]  Charles Werner,et al.  Surface displacement of the March 26, 1997 Kagoshima‐Ken‐Hokuseibu Earthquake in Japan from synthetic aperture radar interferometry , 1998 .

[84]  Brian Taylor,et al.  Geodetic observations of very rapid convergence and back-arc extension at the Tonga arc , 1995, Nature.

[85]  T. Sagiya,et al.  Strain partitioning in the zone of transition from Nankai subduction to Izu–Bonin collision (Central Japan): implications for an extensional tear within the subducting slab , 1999 .

[86]  S. Miyazaki,et al.  Establishment of the nationwide GPS array (GRAPES) and its initial results on the crustal deformation of Japan , 1996 .

[87]  K. Shimazaki,et al.  Deformation of an island arc: Rates of moment release and crustal shortening in intraplate Japan determined from seismicity and Quaternary fault data , 1982 .

[88]  Show Matsumura.  Focal zone of a future Tokai earthquake inferred from the seismicity pattern around the plate interface , 1997 .

[89]  Makoto Murakami,et al.  Detection and Monitoring of Ongoing Aseismic Slip in the Tokai Region, Central Japan , 2002, Science.

[90]  Takao Eguchi,et al.  Detection of a volcanic fracture opening in Japan using Global Positioning System measurements , 1990, Nature.

[91]  S. Miyazaki,et al.  INTERPLATE COUPLING IN SOUTHWEST JAPAN DEDUCED FROM INVERSION ANALYSIS OF GPS DATA , 1999 .

[92]  S. Miyazaki,et al.  Plate convergence and long‐term crustal deformation in central Japan , 2001 .

[93]  K. Ishibashi,et al.  Horizontal Crustal Strain in the Izu Peninsula-Mt. Fuji Region Derived from GEONET Data and its Tectonic Implication , 2003 .

[94]  Teruyuki Kato,et al.  Geodetic evidence of back‐arc spreading in the Mariana Trough , 2003 .

[95]  Yosuke Aoki,et al.  Vertical deformation of the Japanese islands, 1996–1999 , 2003 .

[96]  A preliminary fault model of the 2003 July 26, M6.4 northern Miyagi earthquake, northeastern Japan, estimated from joint inversion of GPS, leveling, and InSAR data , 2003 .

[97]  Christian Rocken,et al.  Calibration of antenna-radome and monument-multipath effect of GEONET—Part 2: Evaluation of the phase map by GEONET data , 2001 .

[98]  X. Pichon,et al.  Transient and permanent deformation of central Japan estimated by GPS: 1. Interseismic loading and subduction kinematics , 2001 .

[99]  M. Hyodo,et al.  A viscoelastic model of interseismic strain concentration in Niigata-Kobe Tectonic Zone of central Japan , 2003 .

[100]  W. Thatcher.  The earthquake deformation cycle at the Nankai Trough, southwest Japan , 1984 .