Large cracks in active lava delta, Kīlauea

Substantial cracks cutting across a lava delta are clear indication that the delta is subsiding as it grows across the unstable pile of interfingering lava flows and fragments built on the steep submarine slope. The larger cracks on this delta are 1-2 m (3-6 ft) wide. Lava flows spread onto the delta from some of the cracks and then, after solidifying, were cut by renewed subsidence and widening of the cracks.