USGS
Hawaiian Volcano 
Observatory

Photo Information


Ground cracks and eruptive fissure of southwest rift zone, 
Kilauea Volcano
Photograph by J.D. Griggs on March 4, 1985

Aerial view from above the uppermost southwest rift zone looking toward the northeast. Rim of Halema`uma`u is at very top of image; note Crater Rim Drive below Halema`uma`u.

The large ground cracks developed over time when magma moved underground from the summit reservoir into the rift zone. The cracks indicate that this area was forced apart or widened as a consequence of magma entering the rift zone. Such ground cracking above a blade-like magma intrusion (whether rising or moving laterally) is typical at Kilauea, Mauna Loa, and other volcanoes.

The dark, shiny lava flows (near side of Crater Rim Drive in image) were erupted on September 24, 1971. The initial fissure broke out between Haleama`uma`u and the southwest caldera rim (top left). Then a new fissure cut across the floor of Halema`uma`u to form a single fissure zone nearly 2 km long. By the next morning, these fissures had stopped erupting and new ones developed along the southwest rift zone 4-12 km from Halema`uma`u. When the eruption ended four days later, the rift zone in this area had widened 1-3 m, as indicated by geodetic surveys and by tape measurements of cracks not covered with new lava.

| Next View | Previous View |


HomeVolcano WatchProductsPhoto GalleryPress Releases
How Hawaiian Volcanoes Work

The URL of this page is http://hvo.wr.usgs.gov/gallery/kilauea/caldera/4303019_caption.html
Contact: hvowebmaster@usgs.gov
Updated: 15 September 1998