SAR INTERFEROMETRY APPLICATIONS IN THE PHILIPPINES USING ERS-1 AND ERS-2: CASE STUDY MAYON VOLCANO AND TAAL VOLCANO

 

Salvador, J.H.G.¹, Kanbara, H.², Suguiura, N. ², Kamada, J. ², Tsukada, M. ³,

Hirose, K. ³, Dayao, A. ⁴, Corpuz, E. ⁵and Baloloy, A. ⁵

¹Mines and Geosciences Bureau

North Avenue, Diliman, Q.C. 1104 Philippines

²Nikko Exploration and Development Co. Ltd.,

7-10 Toranomon 2-chome, Minatoku-Tokyo, Japan

³Earth Remote Sensing Data Analysis Center

Forefront Tower 3-12-1 Kachidoki Chuo-ku Tokyo 104 Japan

⁴Mines and Geosciences Bureau Regional Office No. 5

Daraga, Albay, Philippines

⁵Philippine Institute of Volcanology and Seismology

C.P. Garcia Avenue, U.P Diliman Campus, Diliman, Q.C. 1104, Philipines

 

SAR Interferometry studies were conducted in Mayon and Taal Volcanoes in the Philippines.  In Mayon, we used the ERS-1 and ERS-2 data. In Taal, we used the JERS-1 SAR data. In both cases, differential SAR interferograms were successfully generated.

For Mayon Volcano, we applied the three-pass method. Three ERS-1 datasets dated 1993/11/17, 1993/10/13 and 1997/10/10 were utilized. The baseline perpendiculars are –21m for first pair and –156m for the second pair. Two coherence maps and two interferograms were used. Further processing produced a differential interferogram. The result was refined using a “helper phase”.  The measured displacement along the southwest flank of the volcano amounted to 6cm  and roughly coincides with the tiltmeter record in the Mayon Observatory. 

We applied the two-pass method to the available pair of ERS-2 data dated 1999/03/20 and 1999/08/07. The baseline perpendicular is 105m. A coherence map and interferogram was generated. A DEM was integrated to produce a differential interferogram. The measured displacement along the southwest flank of Mayon Volcano is up to 30cm. Later in February 2000, the volcano erupted.

For Taal Volcano, the three-pass method was applied to the JERS-1 data dated 1995/11/15, 1995/02/24 and 1995/12/29. The baseline perpendiculars are 171m for first pair  and 741m for the second pair.  The resulting differential interferogram shows displacement of more than 10cm along the southwest flank of Taal Volcano.