Pemanfaatan Frekuensi Alamiah Tanah Menggunakan Pengukuran Mikrotremor Tiga Komponen dalam Mendeteksi Kedalaman Batuan Dasar

Authors

  • Erfan Syamsuddin Departemen Geofisika, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Hasanuddin
  • Aulia Puji Astuti Departemen Geofisika, Fakultas MIPA, Universitas Hasanuddin, Makassar, Indonesia
  • Sofian Sofian Stasiun Geofisika Kelas I Palu, Indonesia
  • Dede Muhaimin Aziz Departemen Geofisika, Fakultas MIPA, Universitas Hasanuddin, Makassar, Indonesia
  • Muhammad Habibullah Departemen Geofisika, Fakultas MIPA, Universitas Hasanuddin, Makassar, Indonesia
  • Sindy Yustin Linggi Departemen Geofisika, Fakultas MIPA, Universitas Hasanuddin, Makassar, Indonesia

DOI:

https://doi.org/10.20956/geocelebes.v5i2.14996

Keywords:

HVSR, mikrotremor, site effect

Abstract

Suatu wilayah yang memiliki kondisi geologi yang sama dapat memberikan respon yang berbeda terhadap efek getaran tanah, bergantung pada karakteristik batuan penyusun formasi di wilayah itu. Fenomena ini disebut site effect. Spektra ambient noise yang diperoleh dari pengukuran mikrotremor dapat digunakan untuk menentukan respon suatu site khususnya frekuensi dominan lapisan sedimen. Respon frekuensi ini berhubungan dengan ketebalan lapisan sedimen. Berdasarkan formasi geologinya, Kota Palu tersusun atas endapan aluvium berumur holosen yang menjadi sedimen penyusun paling muda di wilayah tersebut. Penelitian ini bertujuan untuk memperoleh estimasi ketebalan lapisan sedimen di tiga titik pengukuran mikrotremor dari nilai spektrum horizontal to vertical () yang merempresentasi frekuensi dominan (f0) serta kecepatan gelombang geser (Vs) lapisan sedimen. Hasil yang diperoleh memperlihatkan nilai frekuensi dominan tanah f0 <2.5 Hz, hasil inversi kurva HVSR memperlihatkan variasi ketebalan sedimen (Vs < 750 m/s) antara 152 – 186 m yang mengindikasikan lapisan sedimen penyusunnya masuk dalam kategori tebal, sedangkan variasi nilai Vs30 berada antara rentang 291 – 381 m/s. Hasil penelitian ini dapat digunakan sebagai dasar acuan untuk tujuan geoteknik, seperti desain bangunan tahan gempabumi berdasarkan respon frekuensi dominan tanah serta kecepatan gelombang gesernya.

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Published

2021-10-15

How to Cite

Syamsuddin, E., Astuti, A. P., Sofian, S., Aziz, D. M., Habibullah, M., & Linggi, S. Y. (2021). Pemanfaatan Frekuensi Alamiah Tanah Menggunakan Pengukuran Mikrotremor Tiga Komponen dalam Mendeteksi Kedalaman Batuan Dasar. JURNAL GEOCELEBES, 5(2), 159–168. https://doi.org/10.20956/geocelebes.v5i2.14996

Issue

Vol. 5 No. 2: October 2021

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