KARAKTERISASI SINYAL GEMPA VULKANIK GUNUNG KELUD MENGGUNAKAN METODE STA/LTA MISFIT DAN GOODNESS- OF-FIT (STUDI KASUS ERUPSI NOVEMBER 2007); CHARACTERIZATION OF VOLCANO - SEISMIC SIGNAL KELUD VOLCANO USING STA/LTA MISFIT AND GOODNESS-OF-FIT METHOD (CASE STUDY OF ERUPTION ON NOVEMBER 2007)
Brlubis, Lailatul Husna, Wiwit Suryanto
2016 | Disertasi | FMIPAKelud eruption on 4th November 2007 was an geophysically interesting phenomenon to be studied and analyzed. One of analysis to apply is the classification volcanic seismic signals based on STA/LTA ratio pattern that aims to alternative method of classifying signals of volcano seismic. Analysis of seismic signals are conducted to the data record from October 16th to 30th. Each data record indicate STA/LTA pattern. STA/LTA pattern which have similarity grouped in one type. Quantitatively, the similarity is analyzed based on time-frequency misfit and goodness-of-fit criteria. The Similarity of each pattern is evaluated as a function of time with either its amplitude or phase. They are then stated as misfit envelope (EM) and phase misfit (PM) with a scale from 0 to 2.30. Results of misfit calculations show five STA/LTA ratio patterns from Mount Kelud seismic signal. Each pattern is correlated with the type of earthquakes in the name of VT-A, VT-B, low - frequency, multiphase, and tremor. The criteria of time-frequency misfit (EM and PM) of lowest values are 0.28 and 0.18 for VT-A; 0.11 and 0.08 for VT-B; 0.56 and 0.20 for Low Frequency; 0.43 and 0.24 for Multi-Phase; and 0.52 and 0.24 for Tremor. Hence, it can be inferred that the STA/LTA ratio patterns of Mount Kelud seismic signal are in the category of excellent, good,and fair.
Kata Kunci : Mount Kelud, STA/LTA ratio pattern, Time-frequency misfit dan goodness-of-fit
