Migration of seismicity and earthquake interactions monitored by GPS in SE Asia triple junction: Sulawesi, Indonesia

[1] Global Positioning System (GPS) measurements made in Sulawesi, Indonesia, from 1992 to 1999 detected coseismic and transient postseismic deformation related to the 1 January 1996, Mw = 7.9 earthquake on the North Sulawesi (Minahassa) trench. These motions are superimposed on the long-term secular motion (40 mm/yr) of the left-lateral Palu fault in central Sulawesi and continued for about 1.5–2 years. Following the earthquake, a string of earthquakes (of magnitude >6) migrated along the Minahassa trench, from west to east. Subsequently, two earthquakes of magnitude >6 occurred on or near the Palu fault migrating toward the south. Modeling the increase in Coulomb stress generated by the successive earthquakes agrees with the hypothesis of interacting events. An unclamping effect, possibly due to fluid migration in the Palu area, is also suggested by the stress computations and the detected (GPS) displacements.

[1]  Christophe Vigny,et al.  Monitoring of the Palu‐Koro Fault (Sulawesi) by GPS , 1998 .

[2]  R. Mccaffrey,et al.  RECONNAISSANCE MICROEARTHQUAKE SURVEY OF SULAWESI, INDONESIA , 1982 .

[3]  F. Pollitz,et al.  Mantle Flow Beneath a Continental Strike-Slip Fault: Postseismic Deformation After the 1999 Hector Mine Earthquake , 2001, Science.

[4]  John H. Woodhouse,et al.  Determination of earthquake source parameters from waveform data for studies of global and regional seismicity , 1981 .

[5]  P. Reasenberg,et al.  Response of Regional Seismicity to the Static Stress Change Produced by the Loma Prieta Earthquake , 1992, Science.

[6]  Ruth A. Harris,et al.  Introduction to Special Section: Stress Triggers, Stress Shadows, and Implications for Seismic Hazard , 1998 .

[7]  Thierry Beaudouin.  Tectonique active et sismotectonique du systeme de failles decrochantes de sulawesi central (indonesie) , 1998 .

[8]  Boudewijn Ambrosius,et al.  Crustal motion and block behaviour in SE-Asia from GPS measurements , 2001 .

[9]  Raul Madariaga,et al.  The 1996 Earthquakes in Sulawesi, Indonesia , 2000 .

[10]  C. Vigny,et al.  Determining the Sula block kinematics in the triple junction area in Indonesia by GPS , 1998 .

[11]  C. Vigny,et al.  Observing plate motions in S.E. Asia: Geodetic results of the GEODYSSEA Project , 1999 .

[12]  Y. Okada.  Internal deformation due to shear and tensile faults in a half-space , 1992, Bulletin of the Seismological Society of America.

[13]  J. Nábělek.  Geometry and mechanism of faulting of the 1980 El Asnam, Algeria, earthquake from inversion of teleseismic body waves and comparison with field observations , 1985 .

[14]  S. Cox,et al.  High fluid pressures during regional metamorphism and deformation: Implications for mass transport and deformation mechanisms , 1984 .

[15]  J. C. Savage,et al.  Geodetic determination of relative plate motion in central California , 1973 .

[16]  A. Dziewoński,et al.  Centroid-moment tensor solutions for July-September 1995 , 1996 .

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

[18]  J. Chéry,et al.  A Physical Basis for Time Clustering of Large Earthquakes , 2001 .

[19]  Yehuda Bock,et al.  Rapid rotations about a vertical axis in a collisional setting revealed by the Palu Fault, Sulawesi, Indonesia , 1999 .