• Geosciences Journal
• /
• v.22 no.6
• /
• pp.1069-1080
• /
• 2018

The Alaskan Aleutian Islands form one of the world's largest volcanic island chains. The islands are exposed to both direct and indirect damage from continuous volcanic eruptions. Surface deformation is mostly observed before volcanic eruption, but with some volcanoes, such as Ontake Volcano, deformations cannot be detected. In this study, we analyzed volcanic eruptions in the Alaskan Aleutian Islands, which is a region of frequent volcanic eruptions. Based on our results, we predicted the type of eruption that would occur on Baekdusan Volcano according to the presence or absence of surface deformation. For this purpose, 10 sites were selected from areas where recent volcanic activity had occurred in the Aleutian Islands. Additionally, Advanced Land Observing Satellite Phased Array-type L-band Synthetic Aperture Radar (ALOS-PALSAR) and European Remote Sensing (ERS)-1/2 satellite data were obtained from 10 experimental sites. Based on the radar satellite data, the volcanic surface deformations were identified, and the characteristics of the volcanic eruption were quantitatively calculated by determining the presence of surface deformation. The results of this study should facilitate the process of correlation between volcanic eruption and surface deformation.

• Journal of Korean Society for Atmospheric Environment
• /
• v.22 no.E2
• /
• pp.69-77
• /
• 2006

Combined gas and aerosol measurements at a downwind area of the volcanic plume would be essential for helping to access the impact of the volcanic eruption on the local ecosystem and residents. An intensive and the fine time resolution measurement of $SO_2$, sulfate and PM2.5 was made to estimate their distribution in the Kanto area of Japan during the Miyakejima volcanic eruption period. In Tokyo, the 1 hr average $SO_2$ concentration observed before the eruption was 23.9 ppbv, while that of after eruption was 140.4 ppbv. In the Saitama Prefecture, the average concentration of $SO_2$ marked in the present study was two times higher than the average before the volcanic eruption. The PM2.5 mass concentrations in Sitama ranged from 3.8 to $136{\mu}g\;m^{-3}$. Sulfate accounts for $4.4{\sim}39.6%$ of PM2.5 in Sitama. The good correlationship between the concentrations of $SO_2$ and sulfate was obtained. The results of the VAFTAD and HYSPLIT models indicate that $SO_2$, sulfate, and PM2.5 measured in the present study would be expected to be significantly affected by the Miyakejima volcanic plume.

• Ocean and Polar Research
• /
• v.34 no.3
• /
• pp.305-323
• /
• 2012

The ocean's response to the Pinatubo and 1259 volcanic eruptions was investigated using an ocean general circulation model equipped with an energy balance model. Volcanic eruptions release gases into the atmosphere which increases the aerosol optical depth and acts to reduce the incoming short-wave radiation. For example, there was a huge volcanic eruption (Pinatubo) in 1991 which reduced the global mean radiative forcing by about 3 W $m^{-2}$. Two numerical experiments were simulated. The first experiment features the Pinatubo eruption and the second experiment simulates the much larger volcanic eruption that occurred in 1259 when the radiative forcing was reduced by 7 times compared to the Pinatubo event. With the reduced radiative forcing due to the Pinatubo eruption at about 3 W $m^{-2}$ and 1259 eruption at about 21 W $m^{-2}$, the global mean sea surface temperature (SST) decreased to its lowest in the second year after each event by about $0.4^{\circ}C$ and $1.6^{\circ}C$, respectively. Sea surface salinity (SSS) increased substantially in the northern North Pacific, northern North Atlantic, and the Southern Ocean. The reduced SST together with SSS increased ocean convection, which yielded an increase in North Atlantic Deep Water, Antarctic Bottom Water, and North Pacific Intermediate Water production and their outflows. The increase in overturning circulation eventually increased the pole-ward ocean heat fluxes. In conclusion, huge volcanic eruptions perturb the ocean substantially and their hallmarks last for more than a decade, confirming the importance of volcanic eruptions in illustrating the decadal-climate variability recorded in the paleoclimate proxy data for the past million years.

• Korean Journal of Mineralogy and Petrology
• /
• v.33 no.1
• /
• pp.73-86
• /
• 2020

The materials generating from volcanic eruption are volcanic gases, lavas and pyroclastic materials. Volcanic ash which has small-grain size (< 2 mm in diameter) can be moved easily and disperse widely, thus it may affect to communities across hundreds of square kilometers. The impacts from volcanic ash fall on people, structures, equipments, plants and livestock largely depend on ash thickness. According to increasing ash thickness, the intensity and area of damage may increase and affect significant damages not to human health but also to infrastructures. To reduce the impacts from volcanic ash fall, we have to establish the guidances about the nature and extent of the hazard and prepare the actions to increase abilities of communities to manage hazard. Although we don't have any experience caused by volcanic ash fall during and after volcanic eruption, we need to prepare the impacts of volcanic ash fall for future eruption in the areas surrounding Korea.

• The Journal of the Petrological Society of Korea
• /
• v.25 no.2
• /
• pp.143-149
• /
• 2016

Eruptive volumes of three monogenetic volcanoes (Songaksan tuff ring, Biyangdo scoria cone, and Ilchulbong tuff cone) with the youngest eruption age are calculated using the model, applied to Auckland Volcanic Field in New Zealand, to investigate the volcanic eruption scale and to evaluate volcanic hazard of Jeju Island. Calculated eruptive volumes of the volcanoes are $24,987,557m^3$, $9,652,025m^3$, and $11,911,534m^3$, respectively, and the volumes include crater infill, tuff ring (tuff cone), scoria cone, and lava flow. Volcanic explosivity indices of Songaksan tuff ring, Biyangdo scoria cone, and Ilchulbong tuff cone are estimated based on the eruptive volumes to be 3, 2, and 3 respectively, and eruption type is Strombolian to Surtseyan. It is assumed that the amount of emitted sulfur dioxide gas is $2-8{\times}10^3kt/y$ according to the correlation between volcanic explosivity index and volcanic sulfur dioxide index. Recent age dating researches reveal evidences of several volcanic activities during the last 10,000 years indicating the possible volcanic eruption in Jeju Island in the near future. Therefore, it is necessary for appropriate researches regarding volcanic eruption of the island to be accomplished. In addition, establishment of the evaluation and preparation system for volcanic hazard based on the researches is required.

• The Journal of the Petrological Society of Korea
• /
• v.23 no.4
• /
• pp.405-418
• /
• 2014

Ontake Volcano, Japan, began to erupt without any precursors on September 27, 2014, at 11:52 AM, and it caused many losses of life. Although Japan's preparation manual and prevention for volcanic eruptions and volcanic hazards has been well established, it could not prevent damage due to the sudden eruption of the volcano. Soon after the eruption, however, Japan Meteorological Agency (JMA) led many organizations and institutions, including JMA's Volcanic Eruption Prediction Liaison Council, Meteorological Research Institute (MRI) and National Agriculture and Food Research Organization and they understood the eruption situation quickly and shared the information based on their close cooperation and contact systems. Through these efforts, JMA published the unified result to the public, informing the public of the situation around the volcano and about the eruption and of how the residents and climbers around the volcano should react to the volcanic hazards caused by the eruption. The Korean Government can learn how to respond to a future eruption of a volcano, such as Mt. Baekdu which has the potential to erupt in the foreseeable future.

• Economic and Environmental Geology
• /
• v.49 no.3
• /
• pp.181-191
• /
• 2016

We estimate the eruption history and magmatic eruptive volumes of each rock units to evaluate the volcanic eruption scale and volcanic hazard of the Ulleung Island. Especially, Maljandeung Tuff represents about 19~5.6 ka B.P. from $^{14}C$ dating, and Albong Trachyandesite, about 0.005 Ma from K-Ar dating in recent age dating data. These ages reveal evidences of volcanic activities within the last 10,000 years, indicating that the Ulleung Island can classify as an active volcano with possibility of volcanic eruption near future. Accumulated DRE-corrected eruptive volume is calculated at $40.80km^3$, within only the island. The calculated volumes of each units are $3.71km^3$ in Sataegam Tuff, and $0.10km^3$ in Maljandeung Tuff but $12.39km^3$ in accounting the distal and medial part extended into southwestern Japan. Volcanic explosivity indices range 1 to 6, estimating from the volumes of each pyroclastic deposits. The colossal explosivity indices are 5 in Sataegam Tuff, and 6 in Maljandeung Tuff in accounting the distal and medial part. Therefore, it is necessary for appropriate researches regarding possibility of volcanic eruption of the island, and establishment system of the evaluation and preparation for volcanic hazard based on the researches is required.

• Journal of the Korean association of regional geographers
• /
• v.17 no.3
• /
• pp.348-356
• /
• 2011

Someday Mt. Baekdu could erupt by records of orogeny activity until today. This study is to predict influence area of lava flow and volcanic ash by simulation of volcanic eruption in the Mt. Baekdu. Simulation for eruption applied to supposing 7 grade of volcanic explosivity index, season from fall to spring. As a simulation results, lava flewed down into slope of China and volcanic ash diffused over the North Korea. Volcanic ash spreads to Ulneung area after nine hours. It was predicted that 61 cities and villages out of 27 administrative districts of Si-Gun were affected by volcanic ash in North Korea and an immense volume of volcanic ash was blown into farm lands, city areas and forests. This results expected to utilize information for disaster preparation of North Korea and joint research with South-North Korea and China.

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

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