Multi temporal JERS-1 SAR investigation of Mt. Baekdu stratovolcano using differential interferometry

Abstract

Mt. Baekdu, a Cenozoic stratovolcano, was studied using twenty-three JERS-1 SAR and two ERS-2 SAR images. A 70-day ERS-2 interferogram produces a very poor interferogram because of the temporal decorrelation probably due to vegetation and the layover effects. However, JERS-1 SAR data pairs produce coherent interferograms even when some of the time intervals between the data take was as long as 6 years. The measurement of surface changes was numerically implemented from 1992 to 1998 using three different SAR interferometry approaches: i) interferometry with large altitude of ambiguity, ii) 2-pass, and iii) 3-pass differential SAR interferometry (DInSAR). Analysis of 11 differential interferograms indicates that the large surface area surrounding Mt. Baekdu (several tens of kilometers) subsides, particularly the southwestern part of it. When the computed displacement vectors are projected onto the vertical components, the maximum subsidence rate is estimated at 9 cm/year. Although the estimated ubsidence rate is not confirmed in the field due to the lack of ground-truth data and accurate DEMs as well as logistic problems, the results provide important volcano-tectonic implications on the background information for future long-term monitoring of Mt. Baekdu.