SO2 FLUX MEASUREMENT BY DOAS DOAS (DIFFERENTIAL OPTICAL ABSORPTION SPECTROSCOPY) AND ITS APPLICATION AT BROMO ERUPTION ON JUNE 2004

Convention Bandung 2004 (CB2004) The 33^rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

SO2 FLUX MEASUREMENT BY DOAS
DOAS (DIFFERENTIAL OPTICAL
ABSORPTION SPECTROSCOPY) AND ITS
APPLICATION AT BROMO ERUPTION ON
JUNE 2004

Hanik Humaida and Yustinus Sulistyo

BPPTK-Direktorat Volkanologi dan Mitigasi Bencana Geologi

Abstract

SO2 is one of the volcanic gases that can provide information about the state of volcano activity, Commonly, SO2 flux is measured by COSPEC (Correlation Spectroscopy). This equipment has several disadvantages; such as heavy, bog size, expensive and stastic operation only. DOAS (Differential Optical Absorption Spectroscopy) is anew method for SO2 gas flux monitoring that has advantages compares to the COSPEC. Recently, this method has been developed. This DOAS consist of 5 units; namely scan miler, condenser lens, detector, power supply, and a laptop. Its total wieght is up to 11 kg. For operation of DOAS using traverse method, it need lens unit, detector and laptop. The weight is only 2 kg DOAS can be operated as static or traverse method and can be mounted at anyplace.

Measurement of SO2 flux by DOAS has been done at G. Bromo on 12-15 June 2004, after the 8 June eruption. Location of neasurementis about 2 km from eruption source using tripod. This angle of measurement ranges between 10o and 12o width of scan is 45 ^o. Data was analysed by HINAGATA sofware. The result showed that 30 minutes before the volcano produced ash, the flux of SO2 increased from normal condition until 135 ton/day.