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Post-wildfire surface deformation at Batagay, Eastern Siberia, detected by L-band and C-band InSAR
  • Kazuki Yanagiya,
  • Masato Furuya
Kazuki Yanagiya
Hokkaido University, Hokkaido University

Corresponding Author:k.yanagiya@frontier.hokudai.ac.jp

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Masato Furuya
Hokkaido University, Hokkaido University
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Thawing of ice-rich permafrost can form a characteristic landform called a thermokarst. The impact of wildfire on thermokarst development remains uncertain. Here we report on the post-wildfire ground deformation associated with the 2014 wildfire near Batagay, Sakha Republic, Eastern Siberia. We used Interferometric Synthetic Aperture Radar (InSAR) to generate both long-term and short-term deformation maps, and examine the temporal evolution of the post-wildfire ground deformation over the permafrost area. Based on two independent satellite-based microwave sensors, we could validate the measurement uncertainties without relying on in-situ data. The inferred time-series based on L-band ALOS2 InSAR data indicated that cumulative subsidence has been greater than 30 cm since October 2015 at the area of greatest deformation, and that the rate of subsidence is slowed in 2018. Meanwhile, C-band Sentinel-1 InSAR data showed that the temporal evolution was not simply linear but rather include episodic changes. Moreover, we could unambiguously detect frost heave signals that were clearly enhanced inside the burned area during the early freezing season but were absent in the mid-winter. We could reasonably interpret the InSAR-based frost heave signals within a framework of premelting dynamics.
Jul 2020Published in Journal of Geophysical Research: Earth Surface volume 125 issue 7. 10.1029/2019JF005473