S Wave Velocity Structure in Non-tectonic Indo-China by Analyzing the Earthquakes in Sumatra-Java in TATO Station, Taiwan
Keywords:Seismogram Comparison, Negative Anomaly in Front Area of Subduction Zone, Vertical Anisotropy
The velocity structure of S wave under South-East Asia and South China Ocean due to earthquakes in Sumatra-Java subduction zone which data is recorded in TATO, Taiwan seismological station, has been investigated through seismogram analysis in time domain and three components simultaneously. The synthetic seismogram was calculated using GEMINI method, with the inputs are the earth model and the CMT solution of the earthquakes. A low-pas filter with corner frequency of 20 mHz was applied on the seismograms. Applying the deconvolution of unit response on the synthetic seismogram the seismogram comparison was executed in the same unit. The seismogram comparison indicated that the calculation from PREMAN synthetic seismogram deviates significantly from the measured ones. The deviation occurred on the arrival time of surface wave of Rayleigh and Love as well as S body waves. The interpretation results of seismogram analysis using waveform indicate that non-tectonic South-East Asia area in front of subduction zone has strong negative correction of v in the upper mantle and with smaller factor also at earth layers below. This result shows stronger vertical anisotropy than one in PREMAN earth model.
Dalkolmo, J., 1993. Synthetische Seismogramme fuer Eine Sphaerisch Symmetrische, Nichtrotierend Erde durch Direkte Berechnung der Greenschen Funktion, Diplomarbeit, Inst. fuer Geophys., Uni. Stuttgart.
Dreger, D.S., 2002. Time-Domain Moment Tensor INVerse Code (TD-MT_INVC), The Berkeley Seismological Laboratory (BSL), Report Number 8511,
Dziewonski, A.M. and Anderson, D.L., 1981. Preliminary reference Earth model, Phys. of the Earth and Plan. Int., 25, 297 – 356.
Engdahl, E.R., Van Der Hilst, R.D., and Buland, R.P., 1998. Global Teleseismic Earthquake Relocation with Improved Travel Times and Procedures for Depth Determination, Bull. Seism. Soc. Am., 88, 722 - 743.
Friederich, W. and Dalkolmo, J., 1995. Complete Synthetic Seismograms for a Spherically Symmetric Earth by a Numerical Computation of the Green's Function in the Frequency Domain, Geophys. J. Int., 122, 537 - 550.
Grand, S.P., Van Der Hilst, R.D., and Widiyantoro, S., 1997. Global Seismic Tomography; A Snapshot of Convection in the Earth, GSA Today, 7, 1 - 7.
Hall, R., 2002. Cenozoic Geological and Crust Tectonic Evolution of SE Asia and the SW Pacific: Computer Based Reconstructions, Model and Animations, Journ. Of Asian Earth Sciences, 20, 353 – 431.
Kennett, B.L.N., IASPEI 1991, Seismological Tables, Research School of Earths Sciences, Australian National University.
Replumaz, A, Kárason, H, van der Hilst, R. D., Besse, J. and Tapponnier, P., 2004. 4-D Evolution of SE Asia’s Mantle from Geological Reconstructions and Seismic Tomography, Earth and Planetary Science Letters, 221, 103 – 115.