Remote sensing for the volcanic fluid by use of back scattering Raman light

• Project/Area Number: 23656565
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Earth system and resources enginnering
• Research Institution: Tokai University
• Principal Investigator: OHBA Takeshi 東海大学, 理学部, 教授 (60203915)
• Project Period (FY): 2011 – 2013
• Project Status: Completed (Fiscal Year 2013)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2013: ¥130,000 (Direct Cost: ¥100,000、Indirect Cost: ¥30,000); Fiscal Year 2012: ¥260,000 (Direct Cost: ¥200,000、Indirect Cost: ¥60,000); Fiscal Year 2011: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
• Keywords: ラマン光 / 火山 / 流体 / 火口湖 / リモートセンシング / 遠隔観測 / 水蒸気爆発 / レーザー / 火山活動

Research Abstract

We carried out a basic experiment by which the acidity of natural water such as the lake water in active volcanoes. For the exciting light, 532nm 0.6W laser was employed. For the detection of Raman light, a monochrometer and a photomultiplier were used. In a laboratory, water solutions with various acidities were excited by the laser and the back scattering Raman light was observed with the distance of 30 cm. The characteristic Raman light originating in the vibration of H2O molecules were detected at 642 and 650 nm of wave length for the peak in spectra. The relative height of those peaks was correlated to the acidity of solution, implying the possibility of remote sensing of water acidity based on the Raman light observation.