| Title | THERMAL ACTIVITY EXPLORATION AND MONITORING OF RECENTLY ACTIVE KIRISHIMA VOLCANO IN THE SOUTHERN KYUSHU ISLAND IN JAPAN USING SATELLITE IMAGERIES |
|---|---|
| Authors | M.B. Mia, J. Nishijima and Y. Fujimitsu |
| Year | 2017 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | satellite image, hydrothermal alteration, land surface temperature, radiative heat loss, heat Discharge rate, kirishima volcano |
| Abstract | Recently, a Plinian or sub-plinian eruption occurred from January – September 2011 after a long dormant period in the Kirishima volcano at southern Kyushu Island in Japan. Our purpose is to apply satellite images to explore and monitor the recent thermal activity of this volcano. We used a recent Landsat 8 OLI image for exploring the thermal ground using various hydrothermal alteration mapping techniques and three ASTER thermal infrared images for exploration and monitoring heat losses from this volcano before and after the 2011 eruption. Firstly, the most active region was explored using the alteration mapping techniques such as band combination, band ratio and principal component analysis. For heat loss studies, we selected a target area of about 120 sq. km and used the Stefan-Boltzmann equation to derive the radiative heat flux (RHF), NDVI threshold method for emissivity and Split-window algorithm for land surface temperature (LST). Finally, total radiative heat loss (RHL) was multiplied using a relationship coefficient to estimate and monitor the total heat discharge rates (HDR) from this volcano. The result showed that the highest maximum apparent LSTs above ambient were estimated to be about 9°C, 35°C and 6°C respectively in 2009, 2012 and 2015. The maximum RHFs were calculated apparently about 42 W/m2, 177 W/m2 and 29 W/m2 respectively in the year of 2009, 2011 and 2015. Total HDRs were estimated to be about 9294 MW, 60565 MW and 3160 MW respectively in 2009, 2012 and 2015 after multiplying the total RHL of the respective years of the study using the relationship coefficient. The monitoring shows that the thermal activity or heat loss increased sharply by the eruption and decreased after eruption in this active volcano. The study inferred that the applied methods could be used with an effective and efficient way for monitoring the future thermal status of this active volcano using satellite images. |