Estimations of the distribution and eruptive volume of large-scale pyroclastic density current (PDCs) and tephra fall deposits are essential for evaluation of the affected area, long-term volcanic hazards assessments, volcanic activity, and geophysical and petrological quantitative analysis at caldera volcanoes. For this study, the original distributions and eruptive volumes of large-scale PDC (up to 166 km runout distance) and tephra fall deposits derived from the last 87–89 ka caldera-forming eruption (named Aso-4) of Aso volcano in Japan were reevaluated. The original distributions and volumes of PDC deposits just after the eruption were estimated using 3,600 data from geological maps, published research papers, and borehole thickness. The original distributions and volumes of tephra falls were estimated from new isopach maps based on thickness and distribution data of submarine, lacustrine, and subaerial tephra fall deposits. The estimated original volume of the Aso-4 PDC deposits is 340–935 km³ (5.6–14.8 × 10¹⁴ kg). The estimated original volume of the Aso-4 tephra fall deposit is 590–920 km³ (6.0–9.3 × 10¹⁴ kg). The total eruptive volume of the Aso-4 eruption was 930–1,860 km³ (1.2–2.4 × 10¹⁵ kg). This estimation result is about 1.5 to 3 times larger than the previous estimation (>600 km³). Thus, the Aso-4 eruption is now defined as a M8.1–8.4 (VEI8) super-eruption. The Aso-4 results to be the largest eruption in Japan and the 2nd largest eruption in the world (after the 74 ka Toba eruption) in the last 100 ka.

大型火山碎屑密度流（PDC）和特非拉瀑布沉积物的分布和喷发量的估算对于评估受灾地区，长期火山灾害评估，火山活动以及破火山口火山岩的地球物理和岩石定量分析至关重要。在本研究中，源自日本麻生火山最后87-89 ka火山口形成喷发（称为麻生4）的大型PDC（最大跳动距离为166 km）和特非拉瀑布沉积物的原始分布和喷发量重新评估。喷发后PDC矿床的原始分布和储量是使用地质图，已发表的研究论文和井眼厚度的3600个数据估算的。根据海底，湖相和地下天河落差沉积物的厚度和分布数据，根据新的等渗线图估算了天河落差的原始分布和体积。Aso-4 PDC矿床的估计原始量为340–935 km³（5.6-14.8×10 ¹⁴公斤）。Aso-4特弗拉秋天沉积物的原始体积估计为590-920 km ³（6.0-9.3×10 ¹⁴ kg）。Aso-4喷发的总喷发量为930-1,860 km ³（1.2-2.4×10 ¹⁵ kg）。该估计结果大约是先前估计（> 600 km ³）的1.5到3倍。因此，现在将Aso-4喷发定义为M8.1–8.4（VEI8）超级喷发。在过去的100 ka中，Aso-4的喷发量是日本最大的喷发，是世界第二大喷发（在74 ka鸟羽喷发之后）。