Aplikasi Filter Interpolated Finite Impulse Response (IFIR) Pada Data Horizonal To Vertical Spectral Ratio (HVSR)

Olivia, Maya Adinda (2020) Aplikasi Filter Interpolated Finite Impulse Response (IFIR) Pada Data Horizonal To Vertical Spectral Ratio (HVSR). Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Mikrotremor direkam dengan alat yang sangat sensitif terhadap getaran di bawah permukaan tanah, sehingga dapat merekam gelombang frekuensi noise yang tidak diinginkan. Untuk itu perlu dilakukan pengolahan menggunakan filter yang mampu mengatenuasi noise tersebut. Pada penelitian sebelumnya dilakukan dekomposisi sinyal menggunakan operator filter Interpolated Finite Impuse Response (IFIR) dan menghasilkan atenuasi pada nilai frekuensi yang diinginkan. Penelitian ini bertujuan untuk mengetahui karakteristik kurva Horizontal to Vertical Spectral Ratio (HVSR) dan efek noise frekuensi tinggi setelah diberikan filter IFIR. Dari data mikrotremor dilakukan pemberian filter IFIR, smoothing, perhitungan kurva HVSR dan dilakukan perhitungan frekuensi natural (f₀) dan standar deviasi (σ) menggunakan program MATLAB. Proses yang sama dilakukan menggunakan filter Butterworth, Gaussian, dan Cosine sebagai pembanding dengan program Geopsy. Hasilnya, karakteristik amplitudo yang diperoleh mampu memberikan nilai f₀ yang sesuai dengan jenis batuan pada geologi daerah penelitian, yakni f₀ < 2.5 Hz. Nilai standar deviasi filter IFIR yang didapat berkisar antara σ = 0.009 – 0.83 Hz, dengan rata – rata σ ̅= 0.132. Sehingga, filter IFIR mampu memberikan kurva HVSR yang teratenuasi dengan nilai persebaran f₀ yang lebih sesuai daripada filter konvensional lainnya pada cutoff frequency yang ditentukan, yakni 2 Hz. Filter IFIR juga dianggap mampu diaplikasikan pada data Mikrotremor metode HVSR. Filter IFIR lowpass mampu mengatenuasi noise frekuensi tinggi pada data mikrotremor. ========================================================== ========================================================== Microtremor are recorded with a device that is very sensitive to subsurface soil vibrations, that unwanted noise frequency waves are often also included. For this reason, processing needs to be done using filters that can attenuate the noise. In the previous research, signal decomposition was performed using the Interpolated Finite Impuse Response (IFIR) filter and resulted attenuation at the desired frequency value. This study aims to determine the characteristics of the Horizontal to Vertical Spectral Ratio (HVSR) curve and the effect of high frequency noise after being given an IFIR filter. Using the MATLAB program, microtremor data are processed with IFIR filtering, smoothing, calculation of: HVSR curve, natural frequency (f₀) and standard deviation (σ). The same process was carried out using Butterworth, Gaussian, and Cosine filters as a comparison with the Geopsy program. As a result, the amplitude characteristics obtained can provide a value of f₀ that corresponds to the type of rock in the geology of the study area, which is f₀ <2.5 Hz. The standard deviation value of the IFIR filter obtained ranges from σ = 0.009 - 0.83 Hz, with an average of σ ̅= 0.132. In conclusion, the IFIR filter can provide attenuated HVSR curves with better f₀ compared to that of conventional filters according to the specified cutoff frequency at 2 Hz. The IFIR filter is also considered capable of being applied to the HVSR method Microtremor data. Lowpass IFIR filter can attenuate high frequency noise in microtremor data.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: Filter, HVSR, IFIR, Mikrotremor, Sedati Filter, HVSR, IFIR, Microtremor, Sedati
Subjects: Q Science > QC Physics > QC20.7.F67 Fourier transformations
Q Science > QE Geology > QE538.8 Earthquakes. Seismology
Divisions: Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User: Maya Adinda Olivia
Date Deposited: 12 Aug 2020 05:25
Last Modified: 12 Aug 2020 05:25
URI: http://repository.its.ac.id/id/eprint/77659

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