Bulletin of the Volcanological Society of Japan最新文献

{"title":"Ellipse-approximated Isopach Maps for Estimating Ashfall Volume at Sakurajima Volcano(＜Special Section＞Sakurajima Special Issue)","authors":"Tajima Yasuhisa, K. Tamura, T. Yamakoshi, Akira Tsune, Shinjiro Tsurumoto","doi":"10.18940/KAZAN.58.1_291","DOIUrl":"https://doi.org/10.18940/KAZAN.58.1_291","url":null,"abstract":"In studies of volcanic tephra, it is usual that the overall volume of tephra is estimated ashfall volumes based on representative locations within the ashfall area. The precision of the volume estimation largely depends on the number of the locations. However, in the case of ongoing eruptions on island volcanoes, such as Sakurajima volcano, the observation locations are usually limited. We therefore have developed a practical method for estimating ashfall volume and distribution in such case. The method approximates the distribution of ashfall as ellipses, with the distribution area (A) and thickness or weight of deposit (T) determined by A=αT -1 . The ellipse-approximated isopachs can be determined by using the direction of the ellipse axis and ashfall data at two points. In determing the ellipse axis exactly, we usually need additional ashfall amounts from the other locations. We set 37 samplers around Sakurajima volcano, and retrieved the samplers 15 times, from April to December, 2008. Using the propose method, we are able to determine the volume of ash produced by small, continuous eruptions.","PeriodicalId":321973,"journal":{"name":"Bulletin of the Volcanological Society of Japan","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131344423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Inflation-deflation History of Aira Caldera for the Last 120 Years and the Possibility of a Forthcoming Large Eruption at Sakurajima Volcano(＜Special Section＞Sakurajima Special Issue)","authors":"K. Yamashina","doi":"10.18940/KAZAN.58.1_103","DOIUrl":"https://doi.org/10.18940/KAZAN.58.1_103","url":null,"abstract":"In order to assess the potential for future eruptive activity at Sakurajima volcano, southern Japan, ground deformation around northern Kagoshima Bay (i.e., Aira caldera), especially the height change between leveling stations 2474 and 2480, was re-analyzed. Prior to the large eruption in 1914 at Sakurajima volcano, a remarkable inflation was confirmed at Aira caldera, based on re-surveyed data that were not referred to in previous investigations. Considering those data, the upper limit of the magma storage at Aira caldera just before the 1914 eruption could be obtained. Although the 1914 eruption accompanied a remarkable deflation at Aira caldera, magma started to accumulate again and was likely to have exceeded the level observed in 1900 (14 years before the large eruption). Around the early 1970s, it approached the level before the 1914 eruption. After the ground uplift stopped and slightly reversed during a period of extremely frequent explosions at Sakurajima volcano in the 1970s and 1980s, the inflation seems to again be approaching the inferred level before the 1914 eruption, suggesting the possibility of the next large eruption. In addition, inconsistencies between the inferred amounts of magma supply and observed volumes of erupted materials were discussed and left for further study.","PeriodicalId":321973,"journal":{"name":"Bulletin of the Volcanological Society of Japan","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114734268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Separate Quantification of Volcanic Gas Fluxes from Showa and Minamidake Craters at Sakurajima Volcano, Japan(＜Special Section＞Sakurajima Special Issue)","authors":"R. Kazahaya, Toshiya Mori, Keigo Yamamoto","doi":"10.18940/KAZAN.58.1_183","DOIUrl":"https://doi.org/10.18940/KAZAN.58.1_183","url":null,"abstract":"We conducted SO2 flux measurements at Sakurajima volcano, Japan during 2007-2010 to ascertain differences in the degassing activity at two craters of the volcano: Minamidake and Showa craters. Recent developments in SO2 visualization techniques using a UV camera observation system enabled us to quantify the SO2 flux from each crater. SO2 flux reflects conditions of the volcanic conduit. Therefore, a separate estimate of the gas fluxes from different vents is useful to gain insight into conditions within the volcano. Sulfur dioxide flux from Showa crater ranged from a few hundred to several thousand ton/day. In contrast, sulfur dioxide flux of 100-500 ton/day from Minamidake crater remained at a lower level. These results suggest that degassing conditions (i.e. permeability of the conduit or the amount of degassing magma) of Minamidake crater have remained stable. In contrast, the degassing activity of Showa crater is probably variable and sensitive to volcanic activities in the crater. The difference implies that drastic variations of Sakurajima volcanoʼs SO2 flux data, observed using a conventional traverse method with a UV spectrometer, resulted from the Showa craterʼs SO2 flux, not the Minamidake craterʼs SO2 flux.","PeriodicalId":321973,"journal":{"name":"Bulletin of the Volcanological Society of Japan","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124639203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shallow Resistivity Structure of Sakurajima Volcano Revealed by Audio-frequency Magnetotellurics(＜Special Section＞Sakurajima Special Issue)","authors":"W. Kanda, T. Yamazaki, Y. Ogawa, T. Hashimoto, S. Sakanaka, K. Aizawa, S. Takakura, T. Koyama, Kenta Yamada, Tsukasa Kobayashi, S. Komori","doi":"10.18940/KAZAN.58.1_251","DOIUrl":"https://doi.org/10.18940/KAZAN.58.1_251","url":null,"abstract":"Title Shallow Resistivity Structure of Sakurajima Volcano Revealed by Audio-frequency Magnetotellurics Author(s) KANDA, Wataru; YAMAZAKI, Tomoya; OGAWA, Yasuo; HASHIMOTO, Takeshi; SAKANAKA, Shin�ya; AIZAWA, Koki; TAKAKURA, Shinichi; KOYAMA, Takao; YAMADA, Kenta; KOBAYASHI, Tsukasa; KOMORI, Shogo Citation BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN, 58(1): 251-267 Issue Date 2013 Doc URL http://hdl.handle.net/2115/67563 Type article File Information Bull. Volcanol. Soc. Japan58-1_251-267.pdf","PeriodicalId":321973,"journal":{"name":"Bulletin of the Volcanological Society of Japan","volume":"50 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131492021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics of Volcanic Activity at Sakurajima Volcano's Showa Crater During the Period 2006 to 2011(＜Special Section＞Sakurajima Special Issue)","authors":"M. Iguchi, Takeshi Tameguri, Y. Ohta, S. Ueki, S. Nakao","doi":"10.18940/KAZAN.58.1_115","DOIUrl":"https://doi.org/10.18940/KAZAN.58.1_115","url":null,"abstract":". Ishihara, K. (1988) Geophysical evidences on the existence of magma reservoir and conduit at Sakurajima volcano, Japan. Ann. Disast. Prev. Res. Inst., Kyoto Univ., 31B-1, 59-73 (in Japanese with English abstract). Ishihara, K. (1990) Pressure Sources and Induced Ground Deformation associated with Explosive Eruptions at an Andesitic Volcano: Sakurajima Volcano, Japan, In Magma transport and storage (Ed. M.P.Ryan), John Wiley and Sons, 335-356. Ishihara, K. and Eto, T. (1978) Surface deformation associated with the eruptive activity at the summit crater of Sakurajima volcano. Ann. Disast. Prev. Res. Inst., Kyoto Univ., 21B-1, 152-162 (in Japanese with English abstract). Ishihara, K., Takayama, T., Tanaka, Y. and Hirabayashi, J. (1981) Lava flows at Sakurajima volcano ( I ) Volume of the historical lava flows. Ann. Disast. Prev. Res. Inst., Kyoto Univ., 24-1, 1-10 (in Japanese with English abstract). Ishikawa, H., Eto, T., Tanaka, Y. and Ueki, S. (1981) Chronology of eruptive activity of Sakurajima volcano. In Report on Grant-Aid No.A-56-1, 153-179 (in Japanese). Kamo, K. (1978) Some phenomena before the summit eruptions at Sakura-zima volcano. Bull. Volcanol. Soc. Japan, 23, 53-64 (in Japanese with English abstract). Kamo, K. (1988) A dialogue with Sakurajima volcano. In Characteristics of Volcanic Activity at Sakurajima Volcanoʼs Showa Crater During the Period 2006 to 2011 133","PeriodicalId":321973,"journal":{"name":"Bulletin of the Volcanological Society of Japan","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131659976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure of Northeastern Sakurajima, South Kyushu, Japan, Revealed by Seismic Reflection Survey(＜Special Section＞Sakurajima Special Issue)","authors":"T. Tsutsui, Naofumi Yagi, M. Iguchi, Takeshi Tameguri, H. Mikada, K. Onishi, H. Miyamachi, T. Nishimura, Y. Morita, A. Watanabe","doi":"10.18940/KAZAN.58.1_239","DOIUrl":"https://doi.org/10.18940/KAZAN.58.1_239","url":null,"abstract":"Seismic reflection structure in the northeast part of Sakurajima Volcano is discussed down to ca. 11 km with three profiles. Data acquisition was conducted along intersecting two lines with 221 stations and eight shot points. The two lines covered the northeastern portion of the volcano. One of the lines was spread along NNW to SSE direction in the east foot, and another line was oriented east to west in the northern flank of the volcano. Data processing were made through the conventional procedure of the reflection seismology, and depth migrated sections were obtained. Four continuous reflection horizons appear in the profiles. One of the reflection horizons around 5.4 km depth disappears in the northeast portion of the coverage area. The interruption of the horizon suggests existence of magma or magma supply path beneath it. The inferred magma supply path locates to the west of that previously presented.","PeriodicalId":321973,"journal":{"name":"Bulletin of the Volcanological Society of Japan","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116431156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Study of Proximal Eruptive Events in the Large-scale Eruptions of Sakurajima Volcano : An-ei Eruption vs. Taisho Eruption(＜Special Section＞Sakurajima Special Issue)","authors":"M. Yasui, Masaki Takahashi, J. Shimada, D. Miki, K. Ishihara","doi":"10.18940/KAZAN.58.1_59","DOIUrl":"https://doi.org/10.18940/KAZAN.58.1_59","url":null,"abstract":"The An-ei eruption (1779-1782 A.D.) and Taisho eruption (1914-1915 A.D.) were large-scale eruptions of Sakurajima Volcano. The latter, the largest eruption in Japan during the 20 th century, produced about 1.5 km 3 DRE of andesitic magma. In both cases, flank eruptions from two sides of the volcano caused pumice fall and lava flows. The An-ei eruption occurred on the northeastern and southern flanks (An-ei NE and An-ei S eruptions, respectively) and the Taisho eruption occurred on the western and eastern flanks (Taisho W and Taisho E eruptions, respectively). In the An-ei NE, two fissures are recognized from the alignments of craters: the main fissure (5 km long) and a minor fissure (1 km long). A large pyroclastic cone consisting of welded pyroclastic materials was formed along these fissures on the upper to middle flank slopes. Old drawings of the An-ei eruption show that a large amount of pyroclastic materials fell from the eruption column in the proximal area. Thus, the cone was considered to have formed simultaneously with the Plinian eruption. The presence of many cracks and a horse-shoe shaped depression on the cone is attributed to the deformation and collapse of the pyroclastic cone due to gravitational instability on the flank slope of the volcano. A stratigraphy of the eruption products shows that many lava lobes were formed after the initial Plinian eruption. In the An-ei S, the existence of a deformed pyroclastic cone sticking on the steep upper slope below the summit crater and clastogenic lava flows on the downslope indicate the syn-Plinian deposition of pyroclasitc materials on the steep slope. After then, effusion of lavas and some explosions occurred from the chains of craters on the middle flank slope. The An-ei eruption progressed continuously in three stages. The initial Plinian eruption for up to two days on the upfissure (Stage 1) was followed by lava flows on the downfissure (Stage 2). Then, submarine eruption occurred intermittently for about two years on the NE offshore (Stage 3). In the case of the Taisho eruption, initial Plinian eruption (Stage 1) was followed by lava flows associated with the intermittent Vulcanian eruptions (Stage 2) and then, gentle lava outflow continued for more than 1.5 years in the Taisho E in Stage 3. In both eruptions, progress from an explosive pyroclastic eruption at a higher flank in Stage 1 to the effusion of lava at a lower flank in Stage 2 could be explained by the propagation of a radial dyke. Although the pyroclastic cone of the An-ei NE and Taisho W are large in scale, the syn-Plinian clastogenic flow and cone collapse of the Taisho W were extensive. On the other hand, the cone of the An-ei S and Taisho E are small in scale. The cone of the An-ei S was deformed on the steep slope. From these variations, the intensity and duration of the Plinian eruption and the gradient of the flank slope would result in the various morphologies of the resultant cone. Concerning the growth of the edi","PeriodicalId":321973,"journal":{"name":"Bulletin of the Volcanological Society of Japan","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128821759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magma Movement from the Deep to Shallow Sakurajima Volcano as Revealed by Geophysical Observations(＜Special Section＞Sakurajima Special Issue)","authors":"M. Iguchi","doi":"10.18940/KAZAN.58.1_1","DOIUrl":"https://doi.org/10.18940/KAZAN.58.1_1","url":null,"abstract":". Nagata, T., Asada, T. and Suzuki, Z. (1948) Volcanic tremors Masato IGUCHI 16","PeriodicalId":321973,"journal":{"name":"Bulletin of the Volcanological Society of Japan","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121873210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic Velocity Structure of the Crust Beneath the Aira Caldera in Southern Kyushu by Tomography of Travel Times of Local Earthquake Data","authors":"P. Alanis, H. Miyamachi, H. Yakiwara, K. Goto, R. Kobayashi, Takeshi Tameguri, M. Iguchi","doi":"10.18940/KAZAN.57.4_227","DOIUrl":"https://doi.org/10.18940/KAZAN.57.4_227","url":null,"abstract":"We applied the tomography method to the Pand S-wave arrival times of 829 local earthquakes observed at 101 stations in central and southern Kyushu, and revealed the detailed three-dimensional seismic velocity structure of the crust, especially the region beneath the Aira caldera. The structure obtained beneath the Aira caldera was characterized by a compacted high Poisson’s ratio zone at about 20 km depth, suggesting fluid saturation such as partial melts relating to volcanism. We also found that the low frequency earthquakes occurred so as to infill the lower crust between the high Poisson’s ratio zone and the moho discontinuity beneath the Aira caldera. It was also obvious that earthquakes clearly concentrated in regions with low Vp/Vs (low Poisson’s ratio) in the upper crust of the whole of southern Kyushu.","PeriodicalId":321973,"journal":{"name":"Bulletin of the Volcanological Society of Japan","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123880749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radiocarbon Dating of the Minamidake Debris-Avalanche Deposit, Shiretoko-iozan Volcano, Eastern Hokkaido, Japan","authors":"Y. Goto, Nobuo Gouchi, I. Matsuda","doi":"10.18940/KAZAN.56.4-5_161","DOIUrl":"https://doi.org/10.18940/KAZAN.56.4-5_161","url":null,"abstract":"Mt. Shiretoko-iozan is a Quaternary andesitic composite volcano located on the Shiretoko Peninsula, eastern Hokkaido, Japan. An amphitheatre at the summit and a debris-avalanche deposit (Minamidake Debris-Avalanche Deposit) at the western foot of the volcano suggest that sector collapse occurred during its eruptive history. Three trenches ( . , . , and . m deep) were dug at the western terminus of the Minamidake Debris-Avalanche Deposit in order to date the sector collapse event. The stratigraphic section consists of (from lower to upper) : the Sashiruidake Lower Lava, a debris-flow deposit, a buried soil, a debris-flow deposit, a buried soil, the Minamidake Debris-Avalanche Deposit, a buried soil, the Ta-c tephra, and the surface soil. Radiocarbon dating of a buried soil","PeriodicalId":321973,"journal":{"name":"Bulletin of the Volcanological Society of Japan","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125115005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}