slump1.gif. Map of the first two mapped giant landslides (north of O'ahu and Moloka'i). These landslides are the windward halves of the Ko'olau and E Moloka'i volcanoes. Note that they traveled across the Hawaiian Deep and climbed up the inner face of the Hawaiian Arch. Counting contours indicates that the slide from O'ahu climbed 2400 feet (~ 750 meters), a good indication that it was moving quickly rather than slowly creeping along (adapted from Macdonald et al. 1983).