Earth Planets Space, Vol. 65 (No. 6), pp. 527-537, 2013
Taku Ozawa and Tomofumi Kozono
National Research Institute for Earth Science and Disaster Prevention, Japan
(Received November 5, 2012; Revised April 5, 2013; Accepted May 6, 2013; Online published July 8, 2013)
SAR observations to investigate the 2011 Shinmoe-dake
eruption were carried out using several SAR satellites. We detected
temporal variations of the Shinmoe-dake crater in the SAR images. A
convex shape appeared in the PALSAR image acquired on January 27,
but it is unclear whether this shape indicates a lava dome. A
larger convex shape that does indicate a lava dome could be
identified in SAR images acquired after that, and it seems to have
grown progressively. Estimating topography so that the simulated
intensity image corresponds to the acquired one, we estimated that
the lava dome grew from the morning of January 29 until January 31
with a constant effusion rate of 88.7 m3/sec. The lava volume of
15 million m3 estimated from the TerraSAR-X image of February 1
was consistent with that of airborne SAR observation within 20% of
its volume. From the estimated lava effusion rate and lava-covered
area, we estimated that lava viscosity was less than
2.1 GPa·s, suggesting the potential to form a lava flow.
Furthermore, we corrected the foreshortening distortion using the
estimated topography and suggested that the lava effusion point was
around the crater lake.
Key words: Shinmoe-dake, Kirishima, eruption, SAR, lava, volume, viscosity, effusion rate.