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Vico Luthfi Ipmawan

Department Of Physics, Institut Teknologi Sumatera

Author-ID : 4410246

Agriculture, Biological Sciences & Forestry Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Earth & Planetary Sciences Engineering Environmental Science

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Gliding and Quasi-harmonic Tremor Behaviour of Raung Volcano: November 2014 Crisis Period Case Study Ipmawan, Vico Luthfi; Brotopuspito, Kirbani Sri; Triastuty, Hetty
Indonesian Journal on Geoscience Vol 5, No 1 (2018)
Publisher : Geological Agency

DOI: 10.17014/ijog.5.1.13-21The seismic activity of Raung Volcano was raised on 11 November 2014. As many as 1709 tremors were recorded followed by continuous tremors appearing in late November 2014. Quasi-harmonic and gliding tremors appeared in a spectrogram on 12 November 2014. The quasi-harmonic tremors refer to tremors that have no fully harmonic form in spectrum. The gliding harmonic tremors refer to harmonic tremors that have frequency jumps with either positive or negative increment. After signal restitution processing, the Maximum Entropy Spectral Analysis (MESA) method was applied in Raung recordings resulting the spectrum and the spectrogram of tremors. The quasi-harmonic tremors have the monotonic spectrum in its head and centre segment, and the harmonic one in its tails. There are twenty-four spectrums that show frequency changes between the monotonic and harmonic. The similarity between the fundamental frequency range of the monotonic and harmonic ones suggests that both signals are excited from a common resonator. The alternating of monotonic and harmonic respectively over this period is qualitatively similar with Julian’s synthetic time series about the nonlinear oscillator model. It is suggested that Raung Volcano magma pressure is sizeable to make a chaotic vibration. A pressure increasing in Raung magmatic conduit causes the increasing of P-wave velocity and makes a positive gliding frequency.

Gliding and Quasi-harmonic Tremor Behaviour of Raung Volcano: November 2014 Crisis Period Case Study Vico Luthfi Ipmawan; Kirbani Sri Brotopuspito; Hetty Triastuty
Indonesian Journal on Geoscience Vol 5, No 1 (2018)
Publisher : Geological Agency

DOI: 10.17014/ijog.5.1.13-21The seismic activity of Raung Volcano was raised on 11 November 2014. As many as 1709 tremors were recorded followed by continuous tremors appearing in late November 2014. Quasi-harmonic and gliding tremors appeared in a spectrogram on 12 November 2014. The quasi-harmonic tremors refer to tremors that have no fully harmonic form in spectrum. The gliding harmonic tremors refer to harmonic tremors that have frequency jumps with either positive or negative increment. After signal restitution processing, the Maximum Entropy Spectral Analysis (MESA) method was applied in Raung recordings resulting the spectrum and the spectrogram of tremors. The quasi-harmonic tremors have the monotonic spectrum in its head and centre segment, and the harmonic one in its tails. There are twenty-four spectrums that show frequency changes between the monotonic and harmonic. The similarity between the fundamental frequency range of the monotonic and harmonic ones suggests that both signals are excited from a common resonator. The alternating of monotonic and harmonic respectively over this period is qualitatively similar with Julian’s synthetic time series about the nonlinear oscillator model. It is suggested that Raung Volcano magma pressure is sizeable to make a chaotic vibration. A pressure increasing in Raung magmatic conduit causes the increasing of P-wave velocity and makes a positive gliding frequency.

Locating Tremor Source with Polarization and Semblance Methods During the 2014 Crisis Period of Raung Volcano Vico Luthfi Ipmawan; Kirbani Sri Brotopuspito; Hetty Triastuty
Indonesian Journal on Geoscience Vol 7, No 1 (2020)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.7.1.41-49

DOI:10.17014/ijog.7.1.41-49Raung is a basaltic-andesitic volcano with strombolian-type eruptive activity located in East Java Province, Indonesia. The seismic activity of this volcano increased on 11th November 2014 which was dominated by tremors. Due to the difficulty to distinguish the onset of body waves of tremor waveform, polarization and semblance methods were proposed and applied to locate the tremor source. The tremors recorded during November to December 2014 were analyzed. The results showed that the back-azimuth values obtained by the polarization method were around N 288o - 324o E in accordance with the direction of Raung summit, while the incidence angle ranged around N 81o - 89.3o E. The semblance method was performed on 2 x 2 km area around the summit. The result of the tremor source showed the distribution of epicentre extending N52o E to the northeast direction about ±2.1 km away from the Raung summit.

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Journal : IJOG : Indonesian Journal on Geoscience