Analyzing the volcanic product mainly for pyroclastic deposits soon after eruption time is difficult because the gases and ashes usually cover over half more the volcanic field. However the microwave remote sensed system can solve the difficulties. In this paper we demonstrate how the radar system using microwave wavelengths can detect the volcanic products soon after eruption. The main aim of this detection is to estimate the geothermal system, especially for fast assessment purpose.
The existence of pyroclastic deposits implies that explosive eruptions have occurred. Calculation of the volume of the deposits can be used to estimate the size of their parental magma chamber. Our approach for geothermal system in an active volcano is based on primarily understanding the volume and characteristic of pyroclastic rocks (tephra). The study site is located at Mt. Merapi, Indonesia which has been active during the last 5 years.
Fig. 1. Â Backscattering intensity images before (A) and after (B) eruption; ratio image of TAC which shows some features flowing from the volcanic vent (C).
Fig. 2. New volcanic products detected contain pyroclastics and lava flow generated from binarization of ratio image (A) and　pyroclastics dispersal model by elliptical distribution model (B).
Fig. 3. Draping image of volcanic products to DEM 10-m mesh.
Fig. 4. General topographical relief from the north (left) to the south (right) in the west flank of Mt. Merapi.
Source:
Saepuloh A., Koike K., Omura M., Detecting pyroclastic flow deposits and aerial dispersal models by microwave remote sensing to evaluate geothermal system, Abstract of the MMIJ spring regular meeting, Graduate School of Engineering Kyushu University, Japan, pp. 64-66, May 2007.