著者
松本ルミ監修
出版者
池田書店
巻号頁・発行日
2006
著者
内田瑞恵著
出版者
池田書店
巻号頁・発行日
2009

1 0 0 0 革細工入門

著者
森下雅代著
出版者
美術出版社
巻号頁・発行日
2005
著者
石崎 泰男 森田 考美 岡村 裕子 小池 一馬 宮本 亜里沙 及川 輝樹
出版者
特定非営利活動法人 日本火山学会
雑誌
火山 (ISSN:04534360)
巻号頁・発行日
vol.59, no.3, pp.185-206, 2014-09-30 (Released:2017-03-20)

Nantai volcano (2,486m a.s.l.), a near-conical stratovolcano with a summit crater ~1km wide, is located along the volcanic front of NE Japan. To date, the eruptive history and characteristics of this volcano have been poorly studied, except for an explosive eruption that occurred at ~17 cal. ka BP (Stage 2 eruption). In this paper, we present the results of investigation of the stratigraphy of recent proximal eruption products, the tephrostratigraphy of the northeastern foot of the volcano, and new radiocarbon ages. The results show that at least six eruptions of Nantai volcano have occurred after Stage 2 eruption, and we refer to these as Stage 3 eruptions. We identify four tephra layers and one pyroclastic flow deposit in the soil sections above the Stage 2 pumice flow deposit, at the northeastern foot of the volcano. These are classified in the ascending order as: (1) Nantai-Bentengawara Tephra 4 (Nt-Bt4), (2) Bentengawara Pyroclastic Flow Deposit, (3) Nt-Bt3, (4) Nt-Bt2, and (5) Nt-Bt1. The Nt-Bt2 is phreatic fallout with no juvenile material; the other tephra layers are phreatomagmatic fallouts containing juvenile pyroclasts together with ash aggregates. Six Stage 3 eruption products are identified within and around the summit crater: (1) a blocky lava flow (Osawa Lava) exposed on the northern crater wall, (2) a partly dissected scoria cone and (3) a poorly-preserved tuff ring (and its resedimented deposits) on the steep crater floor, (4) a subaqueous lava and associated lava fragments sandwiched by lacustrine deposits, (5) a tuff breccia containing hydrothermally-altered lava block and clayey matrix, and (6) a stratigraphically uppermost phreatomagmatic tephra (Nantai-Yudonoyama Tephra). All the proximal eruption products, except for the subaqueous lava, can be correlated with the tephra layers and the pyroclastic flow deposit on the northeastern foot based on stratigraphic positions, lithologies, and geochemical affinities. Our study reveals that five tephra-forming eruptions (ca. 14, 12, 8, 7.5, and 7 cal. ka BP) and one non-explosive subaqueous eruption (between 12 and 8 cal. ka BP) occurred during Stage 3, from a discrete eruption center inside the summit crater. Moreover, the tephra-forming eruptions were diverse in style, with strombolian (12 cal. ka BP), phreatomagmatic (14, 8, and 7 cal. ka BP), and phreatic (7.5 cal. ka BP) eruptions. Eruption style was determined primarily by vent position and spatiotemporal variations in local hydrological factors (e.g., the presence or absence of a crater lake, wet lacustrine deposits, and streams).

1 0 0 0 Freestyle

著者
大野智著
出版者
角川グループパブリッシング(発売)
巻号頁・発行日
2008

1 0 0 0 開放区

著者
木村拓哉著
出版者
集英社
巻号頁・発行日
2003

1 0 0 0 OA 湯島詣

著者
泉鏡花 著
出版者
春陽堂
巻号頁・発行日
1899