IMAGING OF 3-D SEISMIC TOMOGRAPHY FOR INTERNAL STRUCTURE UNDER THE MOUNTAIN MERAPI USING THE LOTOS-10 SOFTWARE

Authors

  • Ayu Wita Sari STIKES Guna Bangsa Yogyakarta, Jl. Padjajaran No.Kel, Ngringin, Condongcatur, Kec. Depok, Kabupaten Sleman, Daerah Istimewa Yogyakarta 55283
  • Gede Bayu Suparta Jurusan Fisika FMIPA UGM, Bulaksumur Yogyakarta, Senolowo, Sinduadi, Mlati, Kabupaten Sleman, Daerah Istimewa Yogyakarta 55281

DOI:

https://doi.org/10.21009/SPEKTRA.032.05

Keywords:

Mount of Merapi, physical character, Seismic of Tomography, lotos-10

Abstract

Abstrak

Telah dilakukan penelitian pencitraan tomografi seismik 3D untuk stuktur internal di bawah Gunung Merapi dengan empat stasiun pencatat gempa dan gempa vulkanik sebagai sumber sinar gelombang. Penelitian ini menggunakan perangkat LOTOS-10 (Local Tomography Software 10) untuk inversi tomografi seismik 3D. Karakteristik medium bawah Gunung Merapi dapat digambarkan oleh parameter fisis seperti kecepatan gelombang primer dan sekunder. Hasil pengolahan data seismograf menunjukkan metoda tomografi seismik dapat mengungkap struktur bawah permukaan Gunung Merapi melalui distribusi anomali deviasi kecepatan dan Vp/Vs ratio. Kualitas citra yang dihasilkan dengan menggunakan gelombang primer lebih jelas resolusinya dan waktu yang digunakan lebih efesien, sehingga dapat digunakan sebagai informasi mitigasi bencana sebelum gempa erupsi terjadi. Daerah anomali negatif yang diperoleh terletak di bawah puncak Gunung Merapi pada kedalaman 3 - 5 km mempunyai karakter fisis yaitu zona lemah, kurang kompak, panas dan heterogen. Daerah anomali tersebut dapat diinterpretasikan sebagai keberadaan zona materi panas yang berasosiasi dengan sisa dapur magma dangkal.

Kata-kata kunci: Gunung api Merapi, sifat fisis, tomografi seismic, lotos-10.

Abstract

3D seismic tomography imaging research conducted for internal structures under Merapi Volcano with four earthquake recording and volcanic earthquake stations as a source of wave rays. This study used LOTOS-10 (Local Tomography Software 10) for 3D seismic tomography inversion. Characteristics of the medium under Merapi Volcano described by physical parameters such as primary and secondary wave velocities. The result of seismograph data processing shows seismic tomography method can reveal the subsurface structure of the Merapi Volcano through the distribution of deviation anomaly speed and Vp / Vs ratio. Image quality generated by using primary wave more clearly the resolution and time used more efficient, so that can be used as disaster mitigation information before earthquake eruption happened. The negative anomaly area obtained under the peak of Merapi Volcano at a depth of 3 - 5 km has the physical characteristics of weak, less compact, hot and heterogeneous zones. The anomalous region can interpret as the existence of a zone of heat material associated with the rest of the shallow magma kitchen.

Keywords: Mount of Merapi, physical character, Seismic of Tomography, lotos-10.

References

[1] K. Aki and W. H. K. Lee, 1976, “Determination Of Three-Dimensional Velocity Anomalies Under a Seismic Array Using First P Arrival Times from Local Earthquake,” Journal of Geophysical Research, No. 23, Vol. 81, 4381-4399.

[2] BPPTK, 2000, Leaflet:Pesona Merapi, BPPTK, Yogyakarta.

[3] I. Koulakov and S. V. Sobolev, 2006, “A Tomographic Image of Indian Lithosphere Break-off Beneath the Pamir Hindukush Region”, Geophysics Journal International, Vol. 164, p. 425-440.

[4] I. Koulakov et al., 2007, “Joint Inversion of Active and Passive Seismic Data in Central Java,” Geophysics Journal International, Vol. 170, p. 923-932.

[5] I. Koulakov, 2009, “LOTOS Code For Local Earthquake Tomographic Inversion : Benchmarks for Testing Tomographic Algorithms,” Bulletin of Seismological Society of America (BSSA), No. 1, Vol.99, p. 194-214.

[6] W. H. K. Lee and J. C. Lahr, 1972, “Hypo71: A computer Program for Determining Hypocenter, Magnitude, and First Motion Pattern of Local Earthquakes,” Open-File Report U. S. Geological Survey, p. 100. California.

[7] J. M. Londono, 2002, “A Seismic Model for the Volcanic Activity of Nevado del Ruiz Vulcano Colombia,” Thesis, Kyoto University, Kyoto.

[8] C. C. Paige and M. A. Saunders, 1982. “LSQR: An algorithm for sparse linear equations and sparse least squares,” ACM trans. Math. Soft., 8, 43–7

[9] L. K. Steck, et al., 1998. “Crust and Upper Mantle P Wave Velocity Structure Beneath Valles Caldera, New Mexico: Result from the James Teleseismic Tomography Experiment,” Journal Geophys. Res., 103, 24.301-24.320.

[10] J. Um and C. Thurber, 1987, “A Fast Algorithm for Two-Point Seismic Ray Tracing,” Bulletin of The Seismological Society of America, Vol. 77, No. 3, p. 972-966.

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Published

2018-08-30

How to Cite

Sari, A. W., & Suparta, G. B. (2018). IMAGING OF 3-D SEISMIC TOMOGRAPHY FOR INTERNAL STRUCTURE UNDER THE MOUNTAIN MERAPI USING THE LOTOS-10 SOFTWARE. Spektra: Jurnal Fisika Dan Aplikasinya, 3(2), 105–116. https://doi.org/10.21009/SPEKTRA.032.05

Issue

Vol. 3 No. 2 (2018): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 3 Issue 2, August 2018

Section

Articles

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