This paper describes the geology and eruptive history of a Quaternary silicic volcanic complex at Shiribetsu, Hokkaido, Japan, with a focus on volcanic landforms produced by silicic explosive eruptions that were not associated with caldera collapse. The Shiribetsu volcanic complex comprises a dacitic pyroclastic plateau and an overlying dacitic central dome complex. The pyroclastic plateau is 22 × 25 km in size, < 200 m high, and consists of two ignimbrite units (the Km-1 and Km-2 deposits; SiO₂ = 67–68 wt%; total volume ~ 10 km³). The central dome complex is 4–5 km wide, rises to 650 m above the pyroclastic plateau, and comprises two adjoining edifices, which are East and West Shiribetsu (SiO₂ = 62–64 wt%; total volume = 1.6 km³). East Shiribetsu has a conical morphology, whereas West Shiribetsu comprises lava flows and a dome, and has a large amphitheater. A debris avalanche deposit (volume = 1 km³) extends from the amphitheater to the western foot of West Shiribetsu. A dacitic lava dome (volume = 0.2 km³) occurs within the amphitheater. According to the stratigraphic relationships and new fission-track dating, the Shiribetsu volcanic complex evolved as follows: (1) dacitic explosive eruptions at ca. 130 ka (Km-2) and 70 ka (Km-1) produced the pyroclastic plateau; (2) effusive dacitic eruptions at 70 ka (East Shiribetsu) and 60 ka (West Shiribetsu) produced the central dome complex; (3) sector collapse occurred at West Shiribetsu at 50–60 ka; and (4) lava dome formation within the amphitheater at 50 ka. The evolution of the Shiribetsu volcanic complex resembles that of ignimbrite shield volcanoes in the central Andes. Shiribetsu may be the first identified example of ignimbrite shield volcanoes in an island arc setting. We suggest that these are an independent class of explosive silicic volcanoes, distinct from calderas, and form above small magma chambers.

本文介绍了日本北海道Shiribetsu的第四纪硅质火山岩群的地质和喷发历史，重点研究了与火山口倒塌无关的硅质爆炸性火山爆发所形成的火山地貌。Shiribetsu火山复合体包括一个火山成因的火山碎屑高原和一个上覆的冰川成因的中央穹顶复合体。火山碎屑高原的面积为22×25 km，高度小于200 m，由两个火成岩单元组成（Km-1和Km-2沉积物； SiO ₂  = 67-68 wt％；总体积〜10 km ³）。中央穹顶综合体宽4–5 km，上升到火山碎屑高原上方650 m，并包含两个相邻的建筑物，即东部和西部Shiribetsu（SiO ₂  = 62–64 wt％；总体积= 1.6 km ³）。东Shiribetsu具有圆锥形的形态，而West Shiribetsu由熔岩流和圆顶组成，并具有大型圆形剧场。从圆形剧场一直延伸到西涉别西麓的碎片雪崩沉积物（体积= 1 km ³）。大型熔岩穹顶（体积= 0.2 km ³）发生在圆形剧场内。根据地层关系和新的裂变径迹测年，Shiribetsu火山复合体的演化过程如下：（1）大约在1989年的达吉斯爆炸爆发。130 ka（Km-2）和70 ka（Km-1）产生了火山碎屑高原。（2）在70 ka（东部Shiribetsu）和60 ka（West Shiribetsu）喷发的洋气喷发形成了中央穹顶复合体；（3）在Shiribetsu西部发生了60-60 ka的扇形坍塌；（4）圆形剧场内50 ka处的熔岩穹顶形成。Shiribetsu火山复合体的演化类似于安第斯山脉中部的易燃性盾构火山的演化。Shiribetsu可能是在岛弧环境中首次识别的易燃性盾构火山实例。我们建议这些是独立的一类爆炸性硅质火山，与破火山口不同，