IMAGING OF 3-D SEISMIC TOMOGRAPHY FOR INTERNAL STRUCTURE UNDER THE MOUNTAIN MERAPI USING THE LOTOS-10 SOFTWARE
DOI:
https://doi.org/10.21009/SPEKTRA.032.05Keywords:
Mount of Merapi, physical character, Seismic of Tomography, lotos-10Abstract
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
[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 Regionâ€, 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.
Downloads
Published
How to Cite
Issue
Section
License
SPEKTRA: Jurnal Fisika dan Aplikasinya allow the author(s) to hold the copyright without restrictions and allow the author(s) to retain publishing rights without restrictions. SPEKTRA: Jurnal Fisika dan Aplikasinya CC-BY or an equivalent license as the optimal license for the publication, distribution, use, and reuse of scholarly work. In developing strategy and setting priorities, SPEKTRA: Jurnal Fisika dan Aplikasinya recognize that free access is better than priced access, libre access is better than free access, and libre under CC-BY or the equivalent is better than libre under more restrictive open licenses. We should achieve what we can when we can. We should not delay achieving free in order to achieve libre, and we should not stop with free when we can achieve libre.
SPEKTRA: Jurnal Fisika dan Aplikasinya is licensed under a Creative Commons Attribution 4.0 International License.
You are free to:
Share - copy and redistribute the material in any medium or format
Adapt - remix, transform, and build upon the material for any purpose, even commercially.
The licensor cannot revoke these freedoms as long as you follow the license terms.
