Thawing of ice‐rich permafrost and subsequent ground subsidence can form characteristic landforms, and the resulting topography they create is collectively called “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, Eastern Siberia. We used Interferometric Synthetic Aperture Radar (InSAR) to generate both long‐term (1–4 years) and short‐term (subseasonal to seasonal) deformation maps. Based on two independent satellite‐based microwave sensors, we could validate the dominance of vertical displacements and their heterogeneous distributions without relying on in situ data. The inferred time series based on L‐band ALOS2 InSAR data indicated that the cumulative subsidence at the area of greatest magnitude was greater than 30 cm from October 2015 to June 2019 and that the rate of subsidence slowed in 2018. The burn severity was rather homogeneous, but the cumulative subsidence magnitude was larger on the east‐facing slopes where the gullies were also predominantly developed. The correlation suggests that the active layer on the east‐facing slopes might have been thinner before the fire. Meanwhile, C‐band Sentinel‐1 InSAR data with higher temporal resolution showed that the temporal evolution included episodic changes in terms of deformation rate. Moreover, we could unambiguously detect frost heave signals that were enhanced within the burned area during the early freezing season but were absent in the mid‐winter. We could reasonably interpret the frost heave signals within a framework of premelting theory instead of assuming a simple freezing and subsequent volume expansion of preexisting pore water.

中文翻译：

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L波段和C波段InSAR探测到的西伯利亚东部Batagay附近的野火后地面变形

融冰多年冻土的融化和随后的地面沉降可以形成特征性的地形，并且它们产生的地形被统称为“热喀斯特”。野火对热岩溶发展的影响尚不确定。在这里，我们报告了与2014年西伯利亚东部Batagay附近的野火相关的野火后地面变形。我们使用干涉合成孔径雷达（InSAR）生成了长期（1-4年）和短期（从季节到季节）变形图。基于两个独立的基于卫星的微波传感器，我们可以在不依赖于原位数据的情况下验证垂直位移的优势及其异质分布。根据L波段ALOS2 InSAR数据推断的时间序列表明，从2015年10月到2019年6月，最大震级区域的累积沉降大于30 cm，2018年沉降速率减慢。烧伤严重程度相当均匀，但是在主要发育沟壑的东坡上，累积的沉降量更大。相关性表明，朝东的斜坡上的活动层可能在火灾之前较薄。同时，具有较高时间分辨率的C波段Sentinel-1 InSAR数据表明，时间演化包括形变率的周期性变化。此外，我们可以清楚地检测到冻胀信号，这些信号在冰冻早期在燃烧区域内增强，但在冬季中期不存在。