KAJIAN POTENSI BAHAYA GEMPABUMI DAERAH SUMBAWA BERDASARKAN EFEK TAPAK LOKAL

Authors

  • Bambang Sunardi Badan Meteorologi Klimatologi dan Geofisika (BMKG)
  • Daryono Daryono Akademi Meteorologi dan Geofisika (AMG)
  • Januar Arifin Badan Meteorologi Klimatologi dan Geofisika (BMKG)
  • Pupung Susilanto Badan Meteorologi Klimatologi dan Geofisika (BMKG)
  • Drajat Ngadmanto Badan Meteorologi Klimatologi dan Geofisika (BMKG)
  • Boko Nurdiyanto Badan Meteorologi Klimatologi dan Geofisika (BMKG)
  • Sulastri Sulastri Badan Meteorologi Klimatologi dan Geofisika (BMKG)

DOI:

https://doi.org/10.31172/jmg.v13i2.127

Keywords:

efek tapak lokal, mikrotremor, indeks kerentanan seismik, local site effect, Sumbawa, microtremor, HVSR, seismic vulnerability index

Abstract

Telah dilakukan pengukuran mikrotremor di 71 titik di Sumbawa. Daerah penelitian dibatasi pada koordinat 117.21250°-117.22750°BT dan 8.7850°-8.8150°LS. Penelitian ini bertujuan untuk mengetahui karakteristik dinamis kondisi geologi lokal diantaranya frekuensi resonansi (fo) dan indeks kerentanan seismik (Kg) serta nilai percepatan getaran tanah (PGA) menurut formulasi Kannai. Pengukuran mikrotremor dilakukan pada masing-masing titik pengukuran selama 30 menit dengan menggunakan Digital Portable Seismograph. Dari analisa data diperoleh nilai frekuensi resonansi (fo) yang relatif tinggi berkisar antara 24,4 hingga 48,14 Hz dan nilai indeks kerentanan seismik (Kg) yang relatif rendah berkisar antara 0,1 hingga 4,8. Hal ini berkaitan erat dengan kondisi geologi lokal berupa batuan yang masif, sehingga daerah dengan frekuensi resonansi tinggi dan indeks kerentanan yang rendah relatif stabil secara seismik. Nilai PGA di daerah kajian berkisar antara 0,25 hingga 0,36 g. Nilai PGA di daerah kajian menunjukkan variasi yang tidak terlalu mencolok yang menunjukkan nilai PGA lebih banyak dipengaruhi oleh input nilai periode dominan di daerah kajian.

 

Microtremor measurements have been done at 71 points in Sumbawa. The research area is restricted to the coordinate 117.22750°-117.21250°E and 8.7850°-8.8150°S. This study aims to determine the local dynamic characteristics including the resonance frequency (fo), seismic vulnerability index (Kg) and peak ground acceleration (PGA) according to Kannai formulation. Microtremor measurements carried out at each point for 30 minutes using Digital Portable Seismograph. From the data analysis obtained the resonance frequency (fo) value are relatively high ranging from 24.4 to 48.14 Hz and seismic vulnerability index (Kg) values are relatively low ranging from 0.1 to 4.8. It is closely related to local geological conditions in the form of a massive rock, so that area with a high resonance frequency and relatively low vulnerability index is seismically stable. PGA values in the study area ranged from 0.25 to 0.36 g. PGA values showed a less variations that indicate PGA value is more influenced by the input value of the dominant period in the study area.

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Published

2012-08-15

How to Cite

Sunardi, B., Daryono, D., Arifin, J., Susilanto, P., Ngadmanto, D., Nurdiyanto, B., & Sulastri, S. (2012). KAJIAN POTENSI BAHAYA GEMPABUMI DAERAH SUMBAWA BERDASARKAN EFEK TAPAK LOKAL. Jurnal Meteorologi Dan Geofisika, 13(2). https://doi.org/10.31172/jmg.v13i2.127

Issue

Vol. 13 No. 2 (2012)

Section

Article

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