[STT48-P05] Detection of ground motion after Kumamoto earthquake 2016 using the time series interference SAR data.
On April 14, 2016, an earthquake with a magnitude of 6.2 occurred in the Kumamoto district, Kumamoto Prefecture, where the epicenter occurred. Two more days later on April 16, a larger earthquake of 7.3, 7.0 (main shock) occurred, bringing enormous damage to the whole of Kyushu, mainly in Kumamoto Prefecture. The main shock on April 16 was due to the activities of the Futada River fault zone, and large crustal deformation was detected in the Aso caldera. Particularly local variations in Aso city have been noted, and researches are being conducted on large fluctuations in Aso City Uchinomaki, kario, and matoishi.
We used the data of Aso City obtained from April 16 th to the present by synthetic aperture radar (SAR), and detected the variation and verified the accuracy. The oldest data actually used in this study is May 2, and there is an interval of about half a month from April 16. Even after May 2, earthquakes with seismic intensity of 3 or more are measured frequently in Aso city In order to investigate the relationship between these earthquakes and ground changes, we chose the number of electronic reference points of the Geographical Survey Institute in the image for the selection of observation points. The number was 10 in the Ascending image and 12 in the Descending image. A graph of each variation was compared with the leveling survey of the Geographical Survey Institute. As a result, we got about 4 cm difference at large places. However, if it was a small place, it was less than 1 cm, and the number was not small. From this, it is considered that the detection and discovery of the ground deformation by periodic observation after the earthquake in the synthetic aperture radar's differential interference analysis is significant, and in the future it is assumed that more accurate soil change due to error reduction and calibration. We want to continue to detect.