• Korean Journal of Remote Sensing
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• v.35 no.6_3
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• pp.1221-1233
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• 2019

Estimating damage in each sector that can be caused by volcanic ash deposition, is very important to prepare the volcanic ash disaster. In this study, we showed predicted-Korean-volcanic-ash damage of each sector by using volcanic ash diffusion simulation and spatial-data-based volcanic ash damage sector in previous study. To this end, volcanic ash related base maps were generated by collecting and processing spatial information data. Finally, we showed Korean-volcanic-ash-deposition damages by sector using the collected Mt. Aso volcanic ash scenarios via overlapping analysis. As a result, volcanic-ash-related damages were expected to occur in the 162 and 134 districts for each Aso volcanic ash scenarios, since those districts exceeds the minimum volcanic ash damage criterion of 0.01 mm. Finally, we compared possible volcanic ash damages by sectors using collected and processed spatial data, after selecting administrative districts(Scenario 190805- Kangwon-do, Kyungsangbuk-do; Scenario 190811-Chuncheon-si, Hongcheon-si) with the largest amount of volcanic ash deposition.

• Korean Journal of Remote Sensing
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• v.34 no.6_4
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• pp.1519-1529
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• 2018

The volcanic ash can spread out over hundreds of kilometers in case of large volcanic eruption. The deposition of volcanic ash may induce damages in urban area and transportation facilities. In order to respond volcanic hazard, it is necessary to estimate efficiently the diffusion area of volcanic ash. The purpose of this study is to compare in-situ volcanic deposition and satellite images of the volcanic eruption case. In this study, we used Near-Infrared (NIR) channels 7 and 8 of Geostationary Ocean Color Imager (GOCI) images for Mt. Aso eruption in 16:40 (UTC) on October 7, 2016. To estimate deposit area clearly, we applied Principal Component Analysis (PCA) and a series of morphology filtering (Eroded, Opening, Dilation, and Closing), respectively. In addition, we compared the field data from the Japan Meteorological Agency (JMA) report about Aso volcano eruption in 2016. From the results, we could extract volcanic ash deposition area of about $380km^2$. In the traditional method, ash deposition area was estimated by human activity such as direct measurement and hearsay evidence, which are inefficient and time consuming effort. Our results inferred that satellite imagery is one of the powerful tools for surface change mapping in case of large volcanic eruption.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.305-316
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• 2022

Numerous research revealed a strong association between the ionospheric perturbations and various natural hazards. The ionospheric measurements from Global Navigation Satellite System (GNSS) observations provide the state of electron contents in the ionosphere that contributes to investigate the source events. In this study, two geophysical events occurred on 23 January 2018, the 7.9 Mw earthquake in Alaska and Kusatsu-Shiranesan volcanic eruption in Japan, are examined to characterize the fingerprint of each event in the ionosphere. Firstly, we extracted the Total Electron Content (TEC) from GNSS measurements, then isolated disturbed wave signatures from the TEC measurements that is referred to as a traveling ionospheric disturbance (TID). As TIDs are short-term ionospheric variations, the major trend of GNSS TEC measurements should be properly removed. We applied a natural neighbor interpolation method together with a leave-one-out cross validation technique for detrending. After detrending the TEC, the remaining signals are further enhanced by applying a band-pass filter and TIDs are detected from them. Finally, the detected TIDs are verified as the response of the ionosphere to Kusatsu-Shiranesan volcanic eruption and Gulf of Alaska earthquake which propagated through the ionosphere with an average velocity of 530 m/s and 724 m/s, respectively. In addition, a coherence analysis is conducted to discriminate between the signatures from a volcanic explosion and an earthquake. The analysis reveals the TID waveforms from each single event are highly correlated, while a low correlation is found between the TIDs from the earthquake and explosion. This study supports the claim that different geophysical events induce the distinctive characteristics of TIDs that are detectable by the ionospheric measurements of GNSS.

• Korean Journal of Remote Sensing
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• v.33 no.5_1
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• pp.587-598
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• 2017

Volcanic ash is a fine particle smaller than 2 mm in diameters. It falls after the volcanic eruption and causes various damages to transportation, manufacturing industry and respiration of living things. Therefore diffusion information of volcanic ash is highly significant for preventing the damages from it. It is advantageous to utilize satellites for observing the widely diffusing volcanic ash. In this study volcanic ash diffusion information about two eruptions of Mt. Sakurajima were calculated using the geostationary satellite, Communication, Ocean and Meteorological Satellite (COMS) Meteorological Imager (MI) and polar-orbiting satellite, Landsat-8 Operational Land Imager (OLI) and the Thermal InfraRed Sensor (TIRS). The direction and velocity of volcanic ash diffusion were analyzed by extracting the volcanic ash pixels from COMS-MI images and the height was retrieved by adjusting the shadow method to Landsat-8 images. In comparison between the results of this study and those of Volcanic Ash Advisories center (VAAC), the volcanic ash tend to diffuse the same direction in both case. However, the diffusion velocity was about four times slower than VAAC information. Moreover, VAAC only provide an ash height while our study produced a variety of height information with respect to ash diffusion. The reason for different results is measured location. In case of VAAC, they produced approximate ash information around volcano crater to rapid response, while we conducted an analysis of the ash diffusion whole area using ash observed images. It is important to measure ash diffusion when large-scale eruption occurs around the Korean peninsula. In this study, it can be used to produce various ash information about the ash diffusion area using different characteristics satellite images.

• Journal of Environmental Science International
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• v.23 no.3
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• pp.527-532
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• 2014

According to the analysis of volcanic observation data around Korean peninsula, the activities of volcano increase continuously. For example, the volcanic eruption of Mt. Sakurajima is an example, and Mt. Baekdu can be another example potentially. In these regards, developing unified system including realtime prediction and 3D visualization of volcano ash are important to prepare the volcanic disaster systematically. In this technical report, an interactive simulator embedding dispersion algorithm and 3D visualization engine is developed. This system can contribute to the realtime prediction of volcanic disaster scientifically.

• Journal of The Geomorphological Association of Korea
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• v.27 no.1
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• pp.91-102
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• 2020

Earthquakes and volcanic information can vary in type and extent, from raw data to processed data. In order to be able to analyzed and modeled, information needs to be opened in any formats and provided with metadata from the Korea Meteorological Agency and related data production organizations. We propose the metadata and data registry related to volcanic disasters in a form that can be used in conjunction with the Korea Meteorological Administration system that manages earthquake and volcanic data in Korea. The standard registry refers to a virtual system that checks the standards developed for over 20 years in the field of geographic information and receives information registration to grasp the location of geographical features. It is not only data from natural disasters such as earthquakes and volcanoes, but also national environmental survey results, and the cooperation system with other organizations dealing with national land information is also important, so a registry that creates and operates standards is necessary. Therefore, creating and operating the standard registry is necessary and expected to contribute to academic openness and data-driven policy.

• Geophysics and Geophysical Exploration
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• v.16 no.4
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• pp.268-274
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• 2013

Continuous seismic observation of volcanic earthquakes related to migration of magma or gas, is one of the most important methods used to monitor active volcanoes. In this review paper, we introduce the characteristics of volcanic earthquakes and their classification based on locations of foci, waveforms, frequencies, lithology, and source mechanisms. We also present some examples of successful warnings of volcanic eruptions and the present status of some observations of volcanic earthquakes in Japan, the United States, Italy, and New Zealand.

• Journal of Environmental Science International
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• v.23 no.12
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• pp.2121-2127
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• 2014

Analyzing the observational data of volcanic activities around the northern part of Korean peninsula, the odds of volcano eruption increases continuously. For example, the cumulative seismic moment and frequence observed near Mt. Baekdu show a sudden increased values. In this study, predicting the diffusion of volcanic ash for two cases were carried out by using interactive realtime simulator, which was developed during last 2 years as a research and development project. The first case is Sakurajima volcano (VEI=3) erupted in August 2013. The second case is assumed as the volcanic eruption at Mt. Baekdu (VEI=7) under landing circumstance of typhoon Maemi (August 2003) in Korean peninsula. The synoptic condition and ash diffusion for the two cases were simulated by WRF(Weather Research and Forecast) model and Lagrangian dispersion model, respectively. Comparing the simulated result of the first case (i.e., Sakurajima volcano) with satellite image, the diffusion pattern show acceptable result. The interactive realtime simulator can be available to support decision making under volcanic disaster around East Asia by predicting several days of ash dispersion within several minutes with ordinary desktop personal computer.

• Journal of The Geomorphological Association of Korea
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• v.25 no.1
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• pp.97-113
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• 2018

Low-frequency geological natural disaster events such as Pohang earthquake have been occurred. As a results, there's a growing recognition on the importance of education and training for low frequency geological disasters in Korea. In spite of many years of scientific researches on volcanic disaster prevention and preparedness on Baekdusan volcano, the results do not provide the proper scenario for the training for volcanic ash event. Fall 3D volcanic ash diffusion model was run based on wind field data for the last five year, assuming Aso Mountain's explosion with volcanic explosion index 5 for seventy two hours. The management criteria values for proper actions in the previous studies were applied to make a scenario for thirteen groups of the disaster response teams such as train transportation, water supply, electrical facilities and human health. The models on the relationship between education and training for disaster prevention and response were suggested to fulfill the scientific and practical training at local level.

• Korean Journal of Mineralogy and Petrology
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• v.37 no.3
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• pp.111-126
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• 2024

Iceland is located at the middle of the North Atlantic Ocean and there are about 130 volcanoes. Volcanoes in Iceland that are predominantly active include the Reykjanes Volcano Belt, the West Volcanic Zone, the Mid-Island Belt, the East Volcanic Zone, the Northern Volcanic Zone, the Öræfi Volcanic Belt, and the Snæfellsnes Volcanic Belt. In these regions, there are over 30 volcanic systems, each of which is primarily composed of central volcanoes and fissures surrounding them. Since October 24th in 2023, an intensive earthquake swarm in the Svartsengi Volcanic System of the Reykjanes Volcano Belt had been detected by the Icelandic Meteorological Administration's monitoring system. Furthermore, surface uplift near Blue Lagoon which is located about 1.5 km northwest of Þorbjörn, was observed in cGPS data and inSAR images, suggesting magma intrusions in the area. On November 10th, 2023, the frequency and intensity of earthquakes increased, and more than 20,000 earthquakes were recorded with the maximum magnitude M5.3. (the same comment as above) Eventually, fissure eruptions with lava fountains up to 100 m high started in the Sundhnúkur fissure row of the Svarthenghi volcanic system on December 18th, 2023. The eruption ended on December 21st, but a new eruption occurred on January 14th, 2024. Eruptions continued to occur in February, March, May, and August in this area. The volcanic unrest in this area that can lead to future eruptions continues as of September 2024.