Southern Kyushu Research Articles

Petrological studies of volcanic ash from Sakurajima volcano in 2013, Southern Kyushu, Japan

Many petrological studies of volcanic rocks have attempted to better predict future volcanic activity. In this study, we examined volcanic ash samples from Showa Crater in Sakurajima, Japan, which were erupted from January to October 2013. This study was used two types of juvenile material; black vesicular volcanic rock (BVVR) and black non-vesicular volcanic rock (BNVVR) to determine the variable of magmatic processes in the magma conduit during the 2013 eruption. We divided the duration into three periods such as January to April, April to July, and July to October based on the variable tendency of SiO2 contents and volume abundance of the interstitial glasses in BVVR and BNVVR. The estimated melt compositions demonstrate that the variability of SiO2 contents and volume abundance of microcrystal in the groundmass (BVVR and BNVVR) over time were caused by micro-crystallization processes. The estimated of water contents and vesicle volume shows the influence of degassing process in the rock forming. Also, the correlation of petrological features with the number of eruptions and eruptive volumes, exhibit the variable of magma supply into conduit in each period. Consequently, careful monitoring of the petrological features of erupted materials may provide useful constraints on future eruptive activity and thereby assist in the mitigation of volcanic hazards.

霧島・御鉢火山における2003年12月以降の噴気活動と明治～大正時代の火山活動

霧島・御鉢火山における2003年12月以降の噴気活動と明治～大正時代の火山活動

南九州,池田火山の噴火史(＜特集＞火山噴火史解明のための露頭データベース構築の検討)

南九州,池田火山の噴火史(＜特集＞火山噴火史解明のための露頭データベース構築の検討)

Volcano-tectonic Earthquakes during the Stage of Magma Accumulation at the Aira Caldera, Southern Kyushu, Japan

Volcano-tectonic Earthquakes during the Stage of Magma Accumulation at the Aira Caldera, Southern Kyushu, Japan

開聞岳火山の海食崖に露出するテフラ層から得られた炭化木片の放射性炭素年代＜特集＞火山噴火史解明のための露頭データベース構築の検討(3))

開聞岳火山の海食崖に露出するテフラ層から得られた炭化木片の放射性炭素年代＜特集＞火山噴火史解明のための露頭データベース構築の検討(3))

桜島火山および姶良カルデラ地域における61ka以降のマグマ化学組成の時間変化とマグマ溜りシステムの進化(＜特集＞桜島火山)

桜島火山および姶良カルデラ地域における61ka以降のマグマ化学組成の時間変化とマグマ溜りシステムの進化(＜特集＞桜島火山)

桜島火山,安永噴火(1779-1782年)で生じた新島(安永諸島)の成因

桜島火山,安永噴火(1779-1782年)で生じた新島(安永諸島)の成因

Seismic Velocity Structure of the Crust Beneath the Aira Caldera in Southern Kyushu by Tomography of Travel Times of Local Earthquake Data

Seismic Velocity Structure of the Crust Beneath the Aira Caldera in Southern Kyushu by Tomography of Travel Times of Local Earthquake Data

Geochemical and Sr-Nd-Pb Isotopic Constraints on the Origin and Magmatic Evolution of Quaternary Lavas of Sakurajima Volcano, Southern Kyushu Island, Japan(＜Special Section＞Sakurajima Special Issue)

Geochemical and Sr-Nd-Pb Isotopic Constraints on the Origin and Magmatic Evolution of Quaternary Lavas of Sakurajima Volcano, Southern Kyushu Island, Japan(＜Special Section＞Sakurajima Special Issue)

Late Upper Paleolithic-Initial Jomon transitions, southern Kyushu, Japan: Regional scale to macro processes a close look

Neolithization processes are among the most significant changes that have occurred in human history. The timing, order, and appearance of new behavioral elements and causes of behavioral change have been widely investigated. In the Japanese Archipelago, transitions from the Upper Paleolithic to Jomon show the first appearances of Neolithic behavioral elements. Research has commonly yielded inter-regional perspectives comparing technological changes with climate and landscape changes. This paper provides intra-regional comparisons of different environmental variables with technological changes focusing on southern Kyushu, Japan. This paper compares data on climate fluctuations, sea level changes, volcanic eruptions and impacts, and biomes with data on the appearance of and changes in pottery technology and variability, supplemented with studies of stone tools and archaeological features. Results suggest that climatic fluctuations, sea level changes, and biome variability may have had significant impacts on behavioral changes and that volcanic eruptions should be evaluated on an intra-regional and site-based scale.

Geomorphic reconstruction of formation and recession processes of waterfalls of the Kaminokawa river basin on Osumi Peninsula, southern Kyushu, Japan

AbstractTo assess the geomorphological importance of waterfall recession in volcanic bedrock, we examined recession rates of six waterfalls in the lower reaches of Kaminokawa river basin on the Osumi Peninsula in southern Kyushu. The examination was performed with an empirical equation that uses a dimensionless parameter obtained by dimensional analysis of relevant measured factors, including erosive force, size of waterfall, and bedrock resistance. Welded Ata ignimbrite, formed at approximately 110 ka, may have played an initiating role to maintain such waterfalls because it resists weathering more than other local rocks. Estimated recession rates for the six waterfalls range from 0.2 to 3.0 cm/y, which compare with estimated rates for waterfalls in another region characterised by welded ignimbrite. Comparison of equation‐derived recession rates of waterfalls with actual recession distances from confluences supports the idea that an original waterfall will subsequently split into two distinct waterfalls when it recesses past an upstream junction of two channels. Our findings revealed that all six waterfalls likely would have been at almost the same point lower in the watershed in the past, marking the general site of the original waterfall. Moreover, the ancestral original waterfall is highly likely to have started from a point between the caldera rim and present river mouth. There, a knickpoint was likely caused by the river dropping into an inner part of the caldera, possibly just after the eruption of the Ata ignimbrite. The waterfall erodes upstream away from the caldera basin, and this happens to be to the east.

P51 火砕物粒子の気泡形態から推定するマグマの発泡・破砕機構 : 姶良カルデラ・入戸火砕流堆積物における例

P51 火砕物粒子の気泡形態から推定するマグマの発泡・破砕機構 : 姶良カルデラ・入戸火砕流堆積物における例

A24 桜島火山大正噴火の噴火様式とその時間変化(火山の地質・噴火年代 (2), 日本火山学会2005年秋季大会)

A24 桜島火山大正噴火の噴火様式とその時間変化(火山の地質・噴火年代 (2), 日本火山学会2005年秋季大会)

P82 霧島山万膳及び夷守台火山観測施設の観測井岩石コア試料のK-Ar年代(ポスターセッション)

P82 霧島山万膳及び夷守台火山観測施設の観測井岩石コア試料のK-Ar年代(ポスターセッション)

A2-03 2011～12年の連続サンプリングによって発見された桜島昭和火口噴出物の岩石学的サイクル(桜島火山1,口頭発表)

A2-03 2011～12年の連続サンプリングによって発見された桜島昭和火口噴出物の岩石学的サイクル(桜島火山1,口頭発表)

A52 南九州での最近 3 万年間のテフロクロノロジー

A52 南九州での最近 3 万年間のテフロクロノロジー

P45 霧島,大幡山周辺における鬼界アカホヤ噴火前後の火山活動(ポスターセッション,日本火山学会2008年秋季大会)

P45 霧島,大幡山周辺における鬼界アカホヤ噴火前後の火山活動(ポスターセッション,日本火山学会2008年秋季大会)

A40 霧島火山群,えびの高原周辺における最近10,000年間の活動史(火山の物質科学(3),日本火山学会2008年秋季大会)

A40 霧島火山群,えびの高原周辺における最近10,000年間の活動史(火山の物質科学(3),日本火山学会2008年秋季大会)

P34 姶良カルデラ形成に至る前駆的なマグマ活動 : マグマ混合の可能性(ポスターセッション,日本火山学会2008年秋季大会)

P34 姶良カルデラ形成に至る前駆的なマグマ活動 : マグマ混合の可能性(ポスターセッション,日本火山学会2008年秋季大会)

P2-27 姶良カルデラ形成期における珪長質マグマの化学的特徴(ポスターセッション)

P2-27 姶良カルデラ形成期における珪長質マグマの化学的特徴(ポスターセッション)