Mt. Baekdu is a volcano near the North Korea-Chinese border that experienced a few destructive eruptions over the course of its history, including the well-known 1702 A.D eruption. However, signals of unrest, including seismic activity, gas emission and intense geothermal activity, have been occurring with increasing frequency over the last few years. Due to its close vicinity to a densely populated area and the high magnitude of historical volcanic eruptions, its potential for destructive volcanic activity has drawn wide public attention. However, direct field surveying in the area is limited due to logistic challenges. In order to compensate for the limited coverage of ground observations, comprehensive measurements using remote sensing techniques are required. Among these techniques, Differential Interferometric SAR (DInSAR) analysis is the most effective method for monitoring surface deformation and is employed in this study. Through advanced atmospheric error correction and time series analysis, the accuracy of the detected displacements was improved. As a result, clear uplift up to 20 mm/year was identified around Mt. Baekdu and was further used to estimate the possible deformation source, which is considered as a consequence of magma and fault interaction. Since the method for tracing deformation was proved feasible, continuous DInSAR monitoring employing upcoming SAR missions and advanced error regulation algorithms will be of great value in monitoring comprehensive surface deformation over Mt. Baekdu and in general world-wide active volcanoes.

As demonstrated in prior studies, InSAR holds great potential for land cover classification, especially considering its wide coverage and transparency to climatic conditions. In addition to features such as backscattering coefficient and phase coherence, the temporal migration in InSAR signatures provides information that is capable of discriminating types of land cover in target area. The exploitation of InSAR signatures was expected to provide merits to trace land cover change in extensive areas; however, the extraction of suitable features from InSAR signatures was a challenging task. Combining time series amplitudes and phase coherences through linear and nonlinear compressions, we showed that the InSAR signatures could be extracted and transformed into reliable classification features for interpreting land cover types. The prototype was tested in mountainous areas that were covered with a dense vegetation canopy. It was demonstrated that InSAR time series signature analyses reliably identified land cover types and also recognized tracing of temporal land cover change. Based on the robustness of the developed scheme against the temporal noise components and the availability of advanced spatial and temporal resolution SAR data, classification of finer land cover types and identification of stable scatterers for InSAR time series techniques can be expected. The advanced spatial and temporal resolution of future SAR assets combining the scheme in this study can be applicable for various important applications including global land cover changes monitoring.

The unprecedentedly strong 2016 Gyeongju and 2017 Pohang earthquakes on the Korean Peninsula aroused public concern regarding seismic hazards previously considered improbable. In this study, we investigated the effects of recent seismic activity close to the epicenters of both earthquakes in the heavy industrial complex of Ulsan. This was performed using Sentinel-1 InSAR time series data combined with on-site GPS observations and background GIS data. The interpretations revealed ongoing topographic deformation of a fault line and surrounding geological units of up to 15 mm/year. Postseismic migrations through the fault line, coupled with the two earthquakes, were not significant enough to pose an immediate threat to the industrial facilities or the residential area. However, according to InSAR time series analyses and geophysical modelling, strain from the independent migration trend of a fault line and eventual/temporal topographic changes caused by potential seismic friction could threaten precisely aligned industrial facilities, especially chemical pipelines. Therefore, we conducted probabilistic seismic hazard and stress change analyses over surrounding areas of industrial facilities employing modelled fault parameters based on InSAR observations. These demonstrate the potential of precise geodetic survey techniques for constant monitoring and risk assessment of heavy industrial complexes against seismic hazards by ongoing fault activities.

Korean National Land Satellite 1 has been launched with a mission to map national geospatial information and to monitor land resource and disasters on March 22, 2021. The satellite has a precise optical payload of 5 multi-spectral bands (Pan, R, G, B, and NIR). It observes the ground of 12 kilometers width at a 0.5m GSD (Ground Sample Distance) mainly over the Korean Peninsula and global areas of interest during at least four years.The product of National Land Satellite is classified to 4 levels: Basic geometry image based on initial satellite position (Level 1); Precise Ortho-rectified image (Level 2);Reproduced 2D/3D information only with Level 2 (Level 3); and Reproduced 2D/3D information with Precise image(Level 2/3) and other spatial information (Level 4). As the first 0.5m-scale satellite, Level 1 and Level 2 products are open and accessible to the Korean public. In case of Level 2 product, the average location accuracy shows about 1~4m in Korea, depending on the number of available Ground Control Points (GCP) and Level 2 product will produce North Korea Digital Map at 1:5,000 scale. The level 3 and level 4 will be serviced to the public in stage from 2023. The Korea national land satellite can be used to monitor disaster damage, especially for monitoring climate change caused by increasing greenhouse gas emissions through increasing plastic waste. In addition, it is expected that it can be used to generate high value-added spatial information such as 3D spatial information through convergence between various spatial information and land satellite information. Acknowledgment: This work was supported by Ministry of Land, Infrastructure and Transport (MOLIT) of Korean government and Korea Environment Industry & Technology Institute (KEITI) through Plastic-Free Specialized Graduate School funded by Korea Ministry of Environment (MOE).Keywords : #National Land Satellite, #CAS500, #High resolution, #0.5m, #Diaster #plastic waste #climate change