2:00 PM - 2:15 PM
[SVC47-32] Improvement of the realtime volcano observation system based on the satellite infrared imagery and its application to the case of the 2015 Mt Raung eruption
Keywords:satellite remote sensing, indrared imagery, Indonesia
Mt Raung, one of the most active volcanoes in Indonesia, is located in the easternmost of Java, Indonesia and has a large conical edifice with altitude of 3320 m. It has a summit caldera of 2km in diameter approximately 300 m in depth, of which topography is similar to the of Miyakejima formed in 2000. In June, 2015, the volcano erupted and lava continued to effuse in the summit caldera from the pyroclastic cone at the center of the floor. Analysis of high-resolution images (Landsat, SPOT, WV and GE) showed that the effused lava enlarged gradually and covered the entire areas of the caldera floor by the middle of July. At the same time, the accumulated lava bed increased in thickness. The total volume of effused lava and the average effusion rate were estimated to be 5.3×107 m3 and 1.1×106 m3/day, respectively. We also analyzed Himawari-8/AHI images between 1st of June to 31st of August. The time series variations of thermal anomaly (1.6 um, 2.3 um, 3.9 um) showed that there were two pulses in the activity - Pulse I and II, which were divined by a low activity period at the end of July. Through examining the short term variations, we found that the eruption started at 4:30 on 20th of June (UTC) and ceased on 7th of August. Reactivation of the activity, i.e., start of Pulse II, occurred at 21:10 on 1st of August. The activity level was nearly constant through the majority of the period, which can be considered as a characteristic of the effusive eruption involving Strombolian lava fountaining. Several hours ahead of the onset of Pulse II, a small thermal pulse was observed. This can be a precursor to reactivation of the activity. In substitution for SGLI images, NPOSS/VIIRS images (resolution 380m) were analyzed to observe enlargement process of the lava bed on the caldera floor. We could recognize increase in the size of high-temperature areas at the summit on the 11 um images of VIIRS in the period from late June to early July. This is probably showing enlargement of the lava bed on the caldera floor. This result suggests that we can monitor detailed eruptive phenomena by using SGLI images in realtime. Also, the combined analysis proposed here is considered as a useful method for exploring eruption sequence.