• 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.

• 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 the Korean earth science society
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• v.38 no.2
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• pp.115-128
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• 2017

Aso caldera volcano is located in central Kyushu, Japan which is one of the largest caldera volcanoes in the world. Nakadake crater is the only active central cone in Aso caldera. There was an explosive eruption on October 8, 2016, the eruption column height was 11 km, and fallout ash was found 300 km away from the volcano. In this study, we performed a numerical simulation to analyze the ash dispersion and the fallout tephra deposits during this eruption using Ash3D that was developed by the United States Geological Survey. The result showed that the ash would spread to the east and northeast, that could not affect the Korean peninsula, and the volcanic ash was deposited at a place from a distance of 400 km or more in the direction of east and northeast. The result was in close agreement with the identified ashfall deposits. Ash3D can be useful for quick forecast for the effects of hazards caused by volcanic ash.

• 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.

• Korean Journal of Remote Sensing
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• v.30 no.6
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• pp.777-786
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• 2014

Mt. Ontake is the second highest volcano in Japan. On 02:52 Universal Time Coordinated(UTC), 27th September 2014, Ontake volcano began on the large eruption without notice. Due to the recent eruption, 55 people were killed and around 70 people injured. Therefore, This paper performed numerical experiment to analyse damage effect of volcanic ash corresponding to Ontake volcano erupt. The forecast is based on the outputs of the HYSPLIT Model for volcanic ash. This model, which is based on the UM numerical weather prediction data. Also, a quantitative analysis of the ash dispersion area, it has been detected using satellite images from optical Communication, Ocean and Meterological Satellite-Geostationary Ocean Color Imager (COMS-GOCI) images. Then, the GOCI detected area and simulated ash dispersion area were compared and verified. As the result, the similarity showed the satisfactory result between the detected and simulated area. The concordance ratio between the numerical simulation results and the GOCI images was 38.72 % and 13.57 %, Also, the concordance ratio between the JMA results and the GOCI images was 9.05 % and 11.81 %. When the volcano eruptions, volcanic ash range of damages are wide more than other volcanic materials. Therefore, predicting ash dispersion studies are one of main way to reduce damages.

• The Journal of the Petrological Society of Korea
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• v.27 no.1
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• pp.17-24
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• 2018

The volcanic history of the volcanic ash cloud movement recorded in the annals of the Choson dynasty in 1654, presumably due to explosive eruptions from Mt. Baekdu volcano. On October 21, 1654, volcanic ash and volcanic gas erupted from Mt. Baekdu could be interpreted as volcanic ash, which was transported to low altitude by winds of north and northeast winds and descended to the south of the peninsula along with volcanic ash clouds. The affected area appeared northward in the southern boundary of Hamgyeongdo, which is estimated to have moved the volcanic ash from Mt. Baekdu to the south of the Korean peninsula. Clouds of volcanic ash have passed through Jeokseong and Jangdan area, Gyeonggido about 500 km away from Mt. Baekdu. This is interpreted as a result of the formation of a volcanic ash cloud along the ground in a curved shape due to the influence of the prevailing wind, which was formed by Plinian-type eruption at Mt. Baekdu. This is reproduced by numerical simulations on the similar weather pattern model.

• The Journal of the Petrological Society of Korea
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• v.20 no.4
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• pp.243-250
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• 2011

This study considers the historical eruption record in 1702 from the volcanological point of view, which is presumed to have occurred from Mt. Baegdusan volcano. The minium volume of erupted materials is estimated to be $1.2km^3$ when calculated with an empirical formula using an isopach line obtained from two points 140 km away from the vent. The 1702 eruption was a paroxysmal one with VEI of 5. The historical record described a deposition of wind-modified fallout ash by movement of hot ash cloud. To prepare for the future eruption, we have to analyze historical literatures and understand characteristics of volcano.

• The Journal of the Petrological Society of Korea
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• v.22 no.4
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• pp.273-289
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• 2013

Fallout ash is a notorious hazard that can have a variety of damages on agriculture and infrastructure and, most notably to aviation and human health. This study discusses the design of a conceptual model to aid in modeling the dispersal and deposition of ash from Mt. Baekdu volcano. It includes a discussion of assumptions and boundary conditions of the model as well as a detailed diagram of the conceptual model, complete with input parameters, units and equations. The two main processes contained within the model are the dispersal and deposition of ash, the outputs obtained from running the model, if designed, would be the total amount of fine ash contained in the eruption column, distance travelled by ash and ash thickness at surface.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.2
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• pp.139-149
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• 2014

A new technique, namely the combination of satellite and trajectory analysis (CSTA), for exploring the spatio-temporal distribution information of volcanic ash plume (VAP) from volcanic eruption. CSTA uses the satellite derived ash property data and a matching forward-trajectories, which can generate airmass history pattern for specific VAP. In detail, VAP properties such as ash mask, aerosol optical thickness at 11 ${\mu}m$ ($AOT_{11}$), ash layer height, and effective radius from the Moderate Resolution Imaging Spectro-radiometer (MODIS) satellite were retrieved, and used to estimate the possibility of the ash forecasting in local atmosphere near volcano. The use of CSTA for Iceland's Eyjafjallaj$\ddot{o}$kull volcano erupted in May 2010 reveals remarkable spatial coherence for some VAP source-transport pattern. The CSTA forecasted points of VAP are consistent with the area of MODIS retrieved VAP. The success rate of the 24 hour VAP forecast result was about 77.8% in this study. Finally, the use of CSTA could provide promising results for VAP monitoring and forecasting by satellite observation data and verification with long term measurement dataset.