vendredi 21 août 2015

DAICHI-2 Emergency Observations of Sakurajima Volcano












JAXA - ALOS-2 (DAICHI-2) Mission logo.

August 21, 2015

The Japan Aerospace Exploration Agency (JAXA) has been observing the volcanic activity of Sakurajima, Japan using the Advanced Land Observing Satellite-2 “DAICHI-2” (ALOS-2) following a request from the Japan Meteorological Agency (JMA)'s Coordinating Committee for Prediction of Volcanic Eruptions. JAXA was asked to perform an emergency observation as there had been a warning of an eruption since August 16, 2015.

The acquired data are being immediately provided to the Geospatial Information Authority of Japan (GSI) and other related disaster preparation organizations, and being analyzed for crustal deformation. For details of the analysis results by GSI and JAXA, please refer to the following websites respectively:

- GSI Analysis results (in Japanese): http://www.gsi.go.jp/BOUSAI/H27-sakurajima.html

- JAXA Earth Observation and Research Center analysis results (in Japanese): http://www.eorc.jaxa.jp/ALOS-2/img_up/jpal2_sakurajima_20150816-17.htm


Image above: SAR interferometric analysis* image of Sakurajima, Japan acquired by DAICHI-2 (analyzed by JAXA).

The image shows the comparison result of the data acquired on January 4 and August 16, 2015. The deformation of up to about 16 cm closer toward the satellite was observed at the area on the east side of the Minamidake Summit of Sakurajima (indicated by the white square).

DAICHI-2 (ALOS-2) satellite

*SAR interferometric analysis

The Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) aboard the DAICHI-2 (ALOS-2) can measure deformation of the land surface (how much the land surface moves) by observing the same place twice and comparing the data. Such an analysis method is called “SAR interferometry (InSAR)”. The observed difference is indicated by colors. When the land surface comes closer to the satellite, the color coordination (coloration) moves from green, red, blue to green, and when it goes away from the satellite, the coloration moves from green, blue red, to green.

JAXA continues observations by the DAICHI-2 to contribute to disaster preparation organizations monitoring Sakurajima.

Related links:

- Organization for disaster preparation and monitoring through satellites (in Japanese): http://www.sapc.jaxa.jp/work/antidisaster/

- About SAR interferometric analysis (in Japanese): http://www.eorc.jaxa.jp/ALOS-2/img_up/jpal2_howto_insar.htm
   
- About DAICHI-2: http://global.jaxa.jp/projects/sat/alos2/

Images, Text, Credits: National Research and Development Agency and Japan Aerospace Exploration Agency (JAXA).

Greetings, Orbiter.ch

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