Yes, Mount Fuji is a stratovolcano made almost entirely of layers of solidified lava, ash, and volcanic rock. While it has not erupted since the Hoei Eruption in 1707, it is still classified by geologists as an active volcano in 2026. If you were to look inside the mountain, there is a magma chamber deep beneath the surface. During its last major eruption, it did not produce a traditional "lava flow" from the summit but instead ejected massive amounts of volcanic ash and "tephra" from a new vent on its flank, which reached as far as Tokyo. However, historical eruptions over the last 10,000 years have produced extensive basaltic lava flows that created the famous Fuji Five Lakes by damming up local rivers. In 2026, the Japanese government monitors the mountain 24/7 with high-tech sensors for any signs of magma movement. While there is no "active lava" visible at the surface today, the mountain's perfectly conical shape is a direct result of thousands of years of lava accumulating around its vent, standing as a silent reminder of its immense volcanic power.