U.S. Geological Survey - Hawaiian Volcano Observatory
Volcanic Hazards - Lava Zones - Ocean Entry
The following types of volcanic hazards on the Island of Hawai`i are described in the online publication, Volcanic and Seismic Hazards on the Island of Hawai`i, revised and reprinted in 1997.
Lava flows are the most common volcanic hazard on Hawai`i and pose the greatest threat to property. For example, since 1983, lava erupted by Kilauea Volcano has covered 102 km2 of land, claimed 181 houses, and closed the coastal highway as flows resurfaced 13 km of it with as much as 25 m of lava.
Explosive eruptions are relatively rare but pose a serious threat to life when they do occur -- a large explosive eruption in 1790 A.D. killed more than 80 Hawaiian warriors marching across the summit area of the volcano.
Airborne lava fragments
Airborne lava fragments erupted by lava fountains pose a serious hazard only in the immediate vicinity of an erupting vent.
Sulfur dioxide gas
Sulfur dioxide gas, continuously emitted during Kilauea's current long-lived eruption, has resulted in persistent volcanic air pollution in areas of the island downwind of the eruption.
Ground cracks and settling
A lesser volcanic hazard is created by ground movement that occurs when molten rock moves underground; large cracks may appear across roads and other property, and subsidence can cause uneven settling of foundations.