Microtremor analysis to evaluate BMKG region III building, Bali, Indonesia

Subject Areas : Geophysics

Muh Sarkowi ¹ , Rahmat Wibowo ² , Ida Bagus Yogi ³ , Mahmud Yusuf ⁴ , Yohana Boka ⁵

1 - Geophysical Engineering, Engineering Faculty, Universitas Lampung, 35145, Bandar Lampung, Lampung, Indonesia
2 - Geophysical Engineering, Engineering Faculty, Universitas Lampung, 35145, Bandar Lampung, Lampung, Indonesia
3 - Geophysical Engineering, Engineering Faculty, Universitas Lampung, 35145, Bandar Lampung, Lampung, Indonesia
4 - Research & Development Center BMKG, Jakarta, Indonesia,
5 - Geophysical Engineering, Industry and Production Technology Department, Institut Teknologi Sumatera, 35365, South Lampung, Lampung, Indonesia

Received: 2020-12-21 Accepted : 2021-05-05 Published : 2021-05-05

Keywords: vulnerability building, Natural frequency, resonance, Microtremor, Bali,

Abstract :

Bali Island has experienced more than 6 significant earthquakes (magnitude > 6) since 1815, which caused extensive damage to buildings and casualties. The microtremor data analysis in the building of Indonesian meteorology, climatology and geophysics agency (BMKG) Region III Denpasar aims to reduce the risk of building damage and casualties due to the earthquake. The analysis was conducted by measuring microtremor and processing the data to obtain the natural frequency of the soil (f0s HVSR) and building (f0b HVSR), resonance, soil (Kg), and building vulnerability index (Kb) so that the safety of the building can be known in the event of an earthquake. The processing and analyzing results the characteristics of microtremor data get the f0b has a greater value than the f0s value so that the building is relatively safe from resonance. The resonance value of the building with the ground has an (R) value of 6.67% - 13.3%, with an average resonance value of 8.89% which is included in the medium resonance. The location of the building is in an area with a Kg of 8.20 – 10.81, which is included in the category of low to moderate soil vulnerability index, and the Kb has a value of 0.4827x10-6 – 7.9771x10-6, with the first floor having an index highest vulnerability. The f0s, f0b, R, Kg, and Kb show that the building is in the safe category in the event of an earthquake.

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