noun
A mound-shaped protrusion formed by the slow extrusion of viscous lava from a volcano. Technical term used in geology and volcanology.
昭和新山は溶岩円頂丘の一例です。
Shōwa-shinzan is an example of a lava dome.
Compound of 溶岩 (yōgan, 'lava') + 円頂 (enchō, 'round top') + 丘 (kyū, 'hill'). The term is a direct calque of the English 'lava dome'.