Geoinformatics Unit

Preliminary Flood Mapping Following Torrential Rain in Saga, Japan

August 29, 2019

On August 28, 2019, torrential rain hit Saga Prefecture, Japan, triggering floods and landslides. The Geoinformatics Unit, RIKEN Center for Advanced Intelligence Project conducted a preliminary mapping of the affected areas using earth observation data. The Sentinal Asia Program provided ALOS-2 PALSAR-2 data used in this analysis.

To detect the flooded areas, we carried out a change detection analysis using a pre-event SAR data acquired on March 18, 2015, and a post-event SAR data from August 28, 2019. The image below shows the comparison of the color composite of ALOS-2 PALSAR-2 images and the detected flooded areas (blue segments) around Omachi, Saga.

Further Information

Sentinel Asia LINK


The information contained in the map is for general information purposes only. The accuracy of the analysis is not assessed yet. The information is provided by Geoinformatics Unit and while we endeavor to keep the information up to date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the map or the information, products, services, or related graphics contained on it for any purpose. Any reliance you place on such information is therefore strictly at your own risk.


Detected flooded areas (blue segments) around Omachi, Saga.