Shallow Ground Characterization Of Gedongsongo Geothermal Field Based On Microtremor Data

Kanita Nur Izzati, Gatot Yuliyanto, Udi Harmoko

Abstract


The research has been conducted in the Gedongsongo manifestation area, Mount Ungaran Geothermal Field. This study aims to characterize shallow subsurface manifestations using microtremor data. Microtremor data were recorded in Candi Village, Bandungan Subdistrict and Jubelan Village, Sumowono Subdistrict, Semarang Regency. The microtremor recording can be done directly using a seismometer with three components. The microtremor measurement is done by simultaneous recording at two or more points, one of the measurement points is selected in an area that has a hard rock structure to avoid frequency amplification due to ground motion. The spectrum ratio recorded in other areas will be compared with the spectrum ratio recorded in hard rock, so as to obtain the site response to microtremors. Based on the Vp/Vs ratio values, most of the research field is composed of very stiff rock types. The distribution of Poisson's ratio values in the research field ranges from 0.20 - 0.50 and in the steaming ground area the Poisson's ratio values range from 0.10 - 0.47. Based on the Poisson's ratio values, it shows that the research field is partly a water prospect area in the form of hot springs, while partly an area composed of dry rocks filled with steam or gas.

Keywords


Microtremor, Gedongsongo, Geothermal Manifestation, Vp/Vs ratio, Poisson’s ratio

Full Text:

PDF

References


S. Indarto, D. S. Widarto, E. G. Zulkarnain, and I. Setiawan. “Studi batuan vulkanik dan batuan ubahan pada lapangan panas bumi gedongsongo kompleks gunung api ungaran jawa tengah”. vol 16 (1), 2006 pp 30-43.

U. Harmoko, G. Yuliyanto, S. Widada, A.R. Ekasara. “Subsurface structure investigation of sangubanyu geothermal field,” vol 1217, 2019 pp 1-6.

K. Tokimatsu. “Geotechnical site characterization using surface waves.” vol 3, 1995 pp 1333-1368.

Y. Nakamura. “Clear identification of fundamental idea of nakamura’s technique and it’s application.” vol.2656, 2000 pp. 1-8.

J.E. Johnston and N.I. Christensen, “Compressional to shear velocity ratios in sedimentary rocks.” 2000 vol 30 (7), 1993 pp.751-754.

D.S. Sudjono, U. Harmoko, G. Yuliyanto. “Delineation of geothermal manifestation in sangubanyu area based on microtremor hvsr method.” vol.125 14012, 2019 pp. 1-5.

V. Arintalofa, U. Harmoko, G. Yuliyanto. “Subsurface characterization of diwak-derekan geothermal field by hvsr analysis method based on mictrotremor data.” vol 2296 020057 2020, pp. 1-9.

W.B. Hamilton, “Tectonics of the indonesian region.” USA: U.S. Government Printing Office, 1979.

R.W. van Bemmelen, “The geology of indonesia.” Netherland, 1949.

J. Marin, A. Harijoko, S. Pramumijoyo, and H. Humaida, “Studi geomorfologi gunung api dan petrogenesa batuan untuk memahami evolusi vulkanotektonik pada gunung ungaran,” 2015 pp. 447-458.Jakarta.

Y.E. Sugiharto, “The geothermal study of ungaran, Indonesia.” 1305-1309. Houston, 2009 Texas.

O. Novotny. “Seismic surface waves.” 2009 Salvador, Bahia

Marjiyono., Ratdomopurbo., Suharna., M.H. Jazuli, dan R. Setianegara, “Geologi Bawah Permukaan Dataran Klaten Berdasarkan Interpretasi Data Mikrotremor.” vol 15 (1), 2019, pp.3-9.

M. Mirzaoglu and U. Dykmen. “Application of Microtremors to Seismic Microzoning Procedurenal.” vol 6 (3), 2003 143-156.

F. Panzera, S.D. Amico, P. Galea, G. Lombardo, M.R. Gallipoli, and S. Pace “Geophysical Measurements for Site Response Investigation: Preliminary Results on The Island of Malta.” vol 54 (2), 2013. pp.111-128

M. Wathelet, “An improved neighborhood algorithm: parameter conditions and dynamic scaling.” vol. 34 2008, pp. 1-5.

G.P., Hersir, and A. Bjornsson, “Geophysical Exploration for Geothermal Resources. Reykjavík, Iceland: Geothermal Training Programme,” 1991 The United Nations University.

N. Haerudin, F. Alami and Rustadi. “Mikroseismik, mikrotremor, dan microearthquake dalam ilmu kebumian.” 2019 Bandar Lampung: Pusaka Media.

T.H. Silitonga, E.E. Siahaan and A. Suroso. “A Poisson’s Ratio Distribution from Wadati Diagram as Indicator of Fracturing of Lahendong Geothermal Field, North Sulawesi, Indonesia.” Proceeding of World Geothermal Congress, 2005 pp. 1-5.G. Eason, B. Noble, and I.N. Sneddon, “On certain integrals of Lipschitz-Hankel type involving products of Bessel functions,” Phil. Trans. Roy. Soc. London, vol. A247, pp. 529-551, April 1955. (references)




DOI: http://dx.doi.org/10.52155/ijpsat.v38.2.5371

Refbacks

  • There are currently no refbacks.


Copyright (c) 2023 Udi Harmoko

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.