Aerial view from above the south caldera floor toward the north. Halema`uma`u is right of center, and the Hawaiian Volcano Observatory sits atop the caldera rim at top center. Caldera Rim Drive (from left to right) crosses the southwest rift zone, cuts across the surface of the Keanakako`i Ash Member, descends the 20-m tall southwest caldera wall, and crosses a lava flow erupted in September 1974.
The lava flow was erupted from a fissure still visible between Halema`uma`u and the southwest caldera rim. Along the caldera rim, note the multiple step-like fault blocks and two sets of ground cracks extending from where the fissure meets the inner caldera wall.
The largest cone on skyline (top left), Kulani Cone, is on the flank of Mauna Loa.