This parking area is constructed on the surface of the Agatsuma ignimbrite. An excellent view of Maekake and its lower slopes may be had. Observe jagged skyline of the youngest lava flow of Oni-oshidashi (1783) and smooth terrace of the penultimate Kami-no-Butai lava (1108).
View from Stop 7
A volcano seen to the north distance is Kusatsu Shirane, the last eruption of which was experienced in 1983, and to the northeast distance is Azumaya, which had been active 300-400 ka. The Ko-Asama lava dome stands to the south.
Along the left bank of a dry gorge, just south of the parking area, a cross-section of the Agatsuma ignimbrite is exposed for several hundred meters. This gorge bounds the lateral extent of the ignimbrite. It is 1-2 m thick and moderately welded throughout, indicating high emplacement temperature. A reddish top is due to oxidization immediately after the deposition.
The Agatsuma ignimbrite is directly underlain by fallout beds of ash and pumice, a part of which supposedly erupted on 17 July 1783. Interbedding with loess layers, the A' pumice (1596?) and Bu scoria (1108) are exposed down below.
welded Agatsuma ignimbrite
Stop 1 Matori: View of Asama
