IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

4W_2E-P13

Date/Time: July 24 Poster

REALTIME MONITORING OF ACTIVE VOLCANOES IN EAST ASIA USING MODIS ANDMTSAT DATA AND ITS ADVANCEMENT BY GCOM-C1 SGLITakayuki KANEKO1 , Atsushi YASUDA1 , Kenji TAKASAKI2 , Hiroyuki DEN1 , Yosuke AOKI11Earthquake Research Insitute, University of Tokyo, Japan, 2 Keio Research Institute at SFC, Japan
E-mail: kaneko@eri.u-tokyo.ac.jp

There are many active volcanoes distributing in east Asia, however, most of them are not well monitored. Monitoring
volcanoes is a key issue for disaster mitigation. Practically, it is not realistic to install ground-based instruments toall of the active volcanoes, because of the cost and manpower for maintenance. Satellite remote sensing is theonly way to monitor these volcanoes existing in such wide areas. We developed a monitoring system basedon infrared images from Moderate Resolution Imaging Spectroradiometer (MODIS) and Multi-functional Transport
Satellite (MTSAT), and are currently observing 147 active volcanoes of this region. In this system, observed results
are immediately uploaded to the website, so that the information can be widely used. Unfortunately, resolution ofMODIS and MTSAT is not sufficient for observing detailed situation of eruptions (MODIS: 1km, MTSAT: 4km).
Japan Aerospace Exploration Agency (JAXA) is lunching the GCOM-C1 satellite carrying Second Generation
Global Imager (SGLI) of which 1.6um, 11um and 12um channels possess 250m resolution, in 2015. Such highresolution infrared images are useful for observing effusing process of small scale lava flows or distribution of small
pyroclastic flows. We worked on improving observation capability of the current system, utilizing images from SGLI,
and developed a method to detect and monitor pyroclastic-flows generation associated with growth of lava dome.
The concept is as follows. As the lava dome grows, the marginal parts of the dome collapse to generate pyroclasticflows. These pyroclastic flows spread and accumulate on the slope. The surface temperature is much lower thanthat of the dome growth area, because of effective cooling in flowing process. On the 1.6um images, the dome
growth area will be radiant, however the depositional areas of pyroclastic flows will not be visible, because of thedetection limit of this channel. On the other hand, on the 11um images pyroclastic flow deposits will be radiant, as
well as the dome growth area - 11um channel is sensitive to low temperature. Accordingly, size of thermal anomaly
will be larger on the 11um than on the 1.6um images here. In contrast, in the case of activities without pyroclastic
flows, both on the 1.6um and 11um images, the sizes of thermal anomaly will be about the same, because of
no hot materials existing around the lava dome. We tested this discrimination method, using simulated SGLI data
produced from Landsat TM of the Unzen 1991-1992 activity. The results showed that activities with pyroclastic flows
have systematically higher 11um /1.6um size ratios than those without pyroclastic flows, as expected. We plan to
add this discrimination method to the system for realtime monitoring pyroclastic-flow generation. Pyroclastic flows
are most destructive volcanic phenomena, so, this kind of information will be useful for mitigation of volcano-related
disasters in east Asia.

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